Early versus late erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

Aher SM, Ohlsson A

Background - Methods - Results - Characteristics of Included Studies - References - Data Tables and Graphs - Additional Tables

Title

Early versus late erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

Reviewers

Aher SM, Ohlsson A

Dates

Date edited: 24/05/2006
Date of last substantive update: 08/05/2006
Date of last minor update: / /
Date next stage expected 01/04/2008
Protocol first published: Issue 3, 2004
Review first published: Issue 3, 2006

Contact reviewer

Dr Sanjay M Aher
Neonatologist
Department of Neonatology
Chelsea and Westminster Hospital
369 Fulham Road
London
UK
SW10 9NH
Telephone 1: 44 07796844728
Facsimile: 44 02082375441
E-mail: ahers1972@yahoo.co.in

Contribution of reviewers

Sanjay Aher (SA) and Arne Ohlsson (AO) contributed equally to all sections of the protocol for this review. The literature search was conducted with the help of an experienced librarian. Both review authors identified potentially eligible studies from the printouts and agreed on which trials to include. Data collection forms were designed and agreed upon by the two review authors. Quality assessments were conducted and data were abstracted by both review authors independently and compared. One review author (AO) entered the data into RevMan 4.2.8 and the other review author (SA) checked for accuracy. One review author (AO) wrote the full review and the other review author (SA) read and made changes. Changes were made by both review authors following feedback from the editors of the review group.

Internal sources of support

Mount Sinai Hospital, Toronto, CANADA

External sources of support

None

Text of review

Synopsis

The number of red blood cells falls after birth in preterm infants due to the natural breakdown of erythrocytes and blood letting. Low levels of erythropoietin (EPO), a substance in the blood that stimulates red blood cell production in preterm infants, provide a rationale for the use of EPO to prevent or treat anemia. A total of 262 infants born preterm have been enrolled in two studies of early vs. late administration of EPO to prevent blood transfusions. There were no demonstrable benefits of early vs. late administration of EPO with regards to reduction in the use of red blood cell transfusions, number of transfusions, the amount of red cells transfused or number of donor exposures per infant. However, the use of early EPO compared to late EPO administration increases the risk of retinopathy of prematurity, a serious complication in babies born before term. Currently, there is lack of evidence that either treatment confers any substantial benefits with regard to any donor blood exposure, as many infants enrolled in both studies were exposed to donor blood prior to study entry, and early EPO increases the risk of retinopathy of prematurity. Neither early nor late administration of EPO is recommended.

Abstract

Background

Hematocrit falls after birth in preterm infants due to physiological factors and frequent blood letting. Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia.

Objectives

To assess the effectiveness and safety of early (before 8 days after birth) versus late (between 8 - 28 days after birth) initiation of EPO in reducing red blood cell transfusions in preterm and/or low birth weight infants.

Search strategy

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2006) was searched. Electronic and manual searches were conducted in November 2005 of MEDLINE, EMBASE and CINAHL, personal files, bibliographies of identified trials and abstracts by the Pediatric Academic Societies' and the European Society of Pediatric Research Meetings published in Pediatric Research.

Selection criteria

Design: Randomized or quasi-randomized controlled trials. Population: Preterm (< 37 weeks gestational age) or low birth weight infants (< 2500 g) less than eight days of age. Intervention: Early initiation of EPO (initiated at < 8 days of age) vs. late initiation of EPO (initiated at 8 - 28 days of age). Outcomes; At least one of the following outcomes were reported: Use of one or more red blood cell transfusions; Total volume (ml/kg) of blood transfused per infant; Number of transfusions per infant; Number of donors to whom the infant was exposed; Mortality during initial hospital stay (all causes); and common outcomes associated with preterm birth.

Data collection & analysis

The standard methods of the Cochrane Neonatal Review Group were followed independently by the authors to assess study quality and report outcomes. Weighted treatment effects, calculated using RevMan 4.2.8 included typical relative risk (RR), typical risk difference (RD), number needed to treat to benefit (NNTB), number needed to treat to harm (NNTH) and mean difference (MD), all with 95% confidence intervals (CI). A fixed effect model was used for meta-analyses. Heterogeneity tests including the I-squared (I2) test were performed to assess the appropriateness of pooling the data.

Main results

Two high quality randomized double-blind controlled studies enrolling 262 infants were identified (Donato 2000; Maier 2002). Both studies used well defined, but not identical, criteria for blood transfusions. Between 14 and 32% of the enrolled infants had received blood transfusions prior to study entry. A non-significant reduction in the 'use one or more red blood cell transfusions' [typical RR 0.91 (95% CI 0.78, 1.06); typical RD - 0.07 (95% CI -0.18, 0.04)] favouring early EPO was noted. Both studies (n = 262) reported on "number of transfusions per infant"; early EPO administration resulted in a non-significant reduction compared to late EPO [typical WMD - 0.32 (95% CI -0.92, 0.29)]. There was no significant reduction in total volume of blood transfused per infant or in the number of donors to whom the infant was exposed. Retinopathy of prematurity (ROP) (all stages) was assessed in 191 infants. Early EPO led to a significant increase in the risk of ROP [(typical RR 1.40 (95% CI 1.05, 1.86); typical RD 0.16 (95% CI 0.03, 0.29); NNTH 6 (95% CI 3 -33)]. There was statistically significant heterogeneity for this outcome. Both studies (n = 191) reported on ROP stage > 3. No statistically significant increase in risk was noted [typical RR 1.56 (95% CI 0.71, 3.41); typical RD was 0.05 (95% CI - 0.04, 0.14)]. There was no statistically significant heterogeneity for this outcome for either RR or for RD. No other important favourable or adverse neonatal outcomes or side effects were reported.

Reviewers' conclusions

The use of early EPO did not significantly reduce the primary outcome of "use of one or more red blood cell transfusions", or "number of transfusions per infant" compared to late EPO administration. Currently there is lack of evidence that early EPO vs. late EPO confers any substantial benefits with regard to any donor blood exposure as a large proportion (14 - 30 %) of infants enrolled in these studies were exposed to donor blood prior to study entry. The finding of a statistically significant increased risk of ROP (any grade) and a similar trend for ROP stage > 3 with early EPO treatment is of great concern. No further studies comparing early vs. late administration of EPO are warranted.

Background

The haemoglobin concentration falls to minimal levels of 11 gm/dl in term infants by 8 to 12 weeks of age and 7.0 to 10.0 gm/dl in preterm infants by 6 weeks of age (Stockman 1978). This process is called physiologic anaemia of infancy (Strauss 1986). In very low birth weight (VLBW) infants, the hematocrit falls to approximately 24 % in infants weighing 1.0 to 1.5 kg and to 21 %in infants weighing less than 1.0 kg at birth (Stockman 1986). In extremely low birth weight (ELBW) infants, this decline in hematocrit is not "physiologic", as it is associated with clinical findings that prompt red blood cell transfusions. The diagnostic accuracy of different clinical signs and laboratory findings has not been studied. It is still unknown how low hematocrit levels can fall before clinical signs of anaemia of prematurity occur and what is the minimal hematocrit level acceptable in infants requiring supplemental oxygen (Ohls 2002). Nevertheless, "top-up" transfusions to treat low haemoglobin or low hematocrit levels are frequently used. As many as 80% of VLBW infants and 95% of ELBW infants receive blood transfusions during their hospitalizations (Widness 1996).

EPO and iron effectively stimulate erythropoiesis. Plasma erythropoietin (EPO) levels in neonates are lower than those for older children and adults. Brown and colleagues reported that, between day two and 30 of life, the mean EPO concentration was 10 mIU/ml, as compared to 15 mIU/ml in concurrently studied adults (Brown 1983). A low plasma erythropoietin (EPO) level is a key reason that nadir hematocrit values of preterm infants are lower than those of term infants (Stockman 1986; Dallman 1981). Low plasma EPO levels provide a rationale for use of EPO in the prevention or treatment of anaemia of prematurity. Studies in newborn monkeys and sheep have demonstrated that neonates have a large volume of distribution and more rapid elimination of EPO, necessitating the use of higher doses than required for adults (Ohls 2000). A recent systematic review of EPO administration noted a wide range of doses used, from 90 to 1400 IU/kg/week (Kotto-Kome 2004). Side effects reported in adults include hypertension, bone pain, rash and rarely seizures. Only transient neutropenia has been reported in neonates (Ohls 2000).

The primary goal of EPO therapy is to reduce transfusions. Most transfusions are given during the first three to four weeks of life. The larger or stable preterm infants, who respond best to EPO, receive few transfusions. ELBW infants, who are sick and have the greatest need for RBC transfusions shortly after birth, have not consistently responded to EPO. This suggests that EPO is a more effective erythropoietic stimulator in more mature neonates. ELBW neonates are more likely to need transfusions even if their erythropoiesis is stimulated (Kotto-Kome 2004). In addition, ELBW neonates have a smaller blood volume and the relatively larger phlebotomy volumes that are required during hospital stay often necessitate "early" transfusions. In contrast "late" transfusions are more often given because of anaemia of prematurity (Garcia 2002). Most preterm infants who require blood transfusions will receive their first transfusion in the first two weeks of life (Zipursky 2000). Reducing the number of RBC transfusions reduces the risk of transmission of viral infections and may reduce costs. Frequent RBC transfusions may be associated with retinopathy of prematurity (Hesse 1997) and bronchopulmonary dysplasia.

Preterm infants need iron for erythropoiesis. As neonatal blood volume expands with rapid growth, infants produce large amounts of haemoglobin. Several studies have observed decrease in serum ferritin concentration - an indication of iron deficiency (Finch 1982) - during erythropoietin treatment. The use of higher, more effective doses of erythropoietin might be expected to be particularly likely to increase iron demand and the risk of iron deficiency (Genen 2004). Iron supplementation during erythropoietin treatment has been observed to reduce the risk of the development of iron deficiency (Shannon 1995). The range of iron doses used in EPO treated infants is between 1 mg/kg/day to 10 mg/kg/day (Kotto-Kome 2004).

The efficacy of EPO in anaemia of prematurity has recently been systematically reviewed (Vamvakas 2001; Garcia 2002; Kotto-Kome 2004). Vamvakas et al concluded that there is extreme variation in the results, and until this variation is better understood, it is too early to recommend EPO as standard treatment for the anaemia of prematurity (Vamvakas 2001). Garcia et al concluded that administering EPO to VLBW neonates can result in a modest reduction in late erythrocyte transfusions and that this effect is dependent on the dose of EPO used (Garcia 2002) . Kotto-Kome et al concluded that if EPO is begun in the first week of life, a moderate reduction can be expected in the proportion of VLBW neonates transfused. The reduction is less significant for early transfusion than for late transfusion (Kotto-Kome 2004).

Additional studies of EPO in preterm or LBW infants have been published since the reviews noted above, justifying additional reviews. The cutoff of less than eight days of age for early and > 8 days for late treatment with EPO, although somewhat arbitrary, was chosen based on previously published meta-analyses (Garcia 2002; Kotto-Kome 2004).

This review compares early administration of EPO (starting in infants less than eight days of age) versus late administration of EPO (starting > 8 days). The main rationale for this review was to evaluate whether early treatment with EPO in preterm infants is more effective than late treatment to decrease exposure to red blood cell transfusion and the total transfusions required. We performed a systematic review to compare all available studies where EPO was begun during first week of life vs. EPO started after the first week of life to assess the effect on any and total number of erythrocyte transfusions.

Objectives

Primary objective:
To assess the effectiveness and safety of early (before eight days after birth) vs. late (between 8 - 28 days after birth) initiation of EPO in reducing red blood cell transfusions in preterm and/or low birth weight infants.

Subgroup analyses:
We planned subgroup analyses within this review for low (< 500 IU/kg/week) and high (> 500 IU/kg/week) doses of EPO, and low (< 5 mg/kg/day) and high (> 5 mg/kg/day) doses of supplemental iron administered by any route.

Criteria for considering studies for this review

Types of studies

Randomised or quasi-randomised controlled trials.

Types of participants

Preterm ( < 37 weeks) and/or low birth weight (< 2500 g) neonates less than eight days of age.

Types of interventions

Early initiation of EPO (initiated before eight days of age, using any dose, route or duration) vs. late initiation of EPO (initiated between 8 - 28 days of age, using any dose, route or duration).

Types of outcome measures

PRIMARY OUTCOME:

Use of one or more red blood cell transfusions.

SECONDARY OUTCOMES:

1. The total volume (ml/kg or ml/kg/day) of red blood cells transfused per infant
2. Number of transfusions per infant
3. Number of donors to whom the infant was exposed
4. Mortality during initial hospital stay (all causes)
5. Retinopathy of prematurity (any stage and stage > 3)
6. Proven sepsis (clinical symptoms and signs of sepsis and positive blood culture for bacteria or fungi)
7. Necrotizing enterocolitis (NEC) (Bell's stage II or more)
8. Intraventricular haemorrhage (IVH); all grades and severe IVH (grades III and IV)
9. Periventricular leukomalacia (PVL); cystic changes in the periventricular areas
10. Length of hospital stay
11. Bronchopulmonary dysplasia (BPD) (supplemental oxygen at 28 days of age or at 36 weeks postmenstrual age and compatible X-ray)
12. Sudden infant death after discharge
13 Long term outcomes assessed at any age beyond one year of age by a validated cognitive, motor, language, or behavioural/school/social interaction/adaptation test
14. Neutropenia
15. Any side effects reported in the trials

Search strategy for identification of studies

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2006) was searched to identify relevant randomised and quasi-randomised controlled trials. MEDLINE was searched for relevant articles published from 1966 to November 2005 using the following MeSH terms or text words: (exp Erythropoietin/OR erythropoietin:.mp. OR rhuepo.mp.) AND (anaemia/OR exp anaemia, neonatal/) AND (blood transfusion/OR blood component transfusion/OR erythrocyte transfusion/) AND (infant, newborn/OR infant, low birth weight/OR infant, very low birth weight/OR infant, premature/OR exp Infant, Premature, Diseases) OR (neonate: OR prematur*: OR newborn:).mp. OR newborn infant [age limit]) AND (clinical trial.pt. OR Randomized Controlled Trials/OR (random: OR rct OR rcts OR blind OR blinded OR placebo:).mp. OR (review.pt. OR review, academic.pt.) AND human. EMBASE from 1980 to November 2005 and CINAHL 1982 to November 2005 using the following MeSH terms or text words: (Erythropoietin/OR erythropoietin: OR epo OR epogen OR epoetin: OR (rhuepo).mp. AND (anaemia/OR exp anaemia, neonatal/) AND (blood transfusion/OR exp blood component transfusion/OR erythrocytes/) AND exp Infant, Premature, Diseases/OR infant, newborn/OR infant, low birth weight/OR infant, very low birth weight/OR infant, premature/OR (neonate: OR newborn: OR prematur*:).mp. OR newborn infant [age limit]. In addition, manual searches of bibliographies and personal files were performed. No language restrictions were applied. Abstracts published from the Pediatric Academic Societies' Meetings and the European Society of Pediatric Research Meetings (published in Pediatric Research) were hand searched from 1980 to April 2006.

Methods of the review

The standard review methods of the Cochrane Neonatal Review Group were used to assess the methodological quality of studies.
All abstracts and published studies identified as potentially relevant by the literature search were assessed for the inclusion in the review by the two review authors. Each review author extracted data separately on a data abstraction form. The information was then compared and differences were resolved by consensus. One review author (AO) entered data into RevMan and the other (SA) cross checked the printout against his own data abstraction forms and any errors were corrected. For the studies identified as abstract, the primary author was to be contacted to obtain further information.

Quality of included trials was evaluated independently by the review authors, using the following criteria:
Blinding of randomisation
Blinding of intervention
Blinding of outcome measure assessment
Completeness of follow up

There are three potential answers to these questions yes, no, cannot tell.

The statistical methods included (typical) relative risk (RR), risk difference (RD), number needed to treat to benefit (NNTB) or number needed to harm (NNTH) for dichotomous outcomes and mean difference (MD) or weighed mean difference (WMD) reported with 95% confidence intervals (CI). A fixed effects model was used for meta-analysis.
Heterogeneity tests including the I-squared (I2) statistic were performed to assess the appropriateness of pooling the data.

Description of studies

Two studies enrolling 268 infants were identified (Donato 2000; Maier 2002). For details of the studies see table "Characteristics of Included Studies". One non-randomized study was excluded (Rudzinska 2002). For transfusion guidelines see Additional table (Table 01 Transfusion guidelines).

Donato 2000: This was a blinded multicenter randomized placebo controlled study conducted in seven private hospitals in Buenos Aires, Argentina between July 1996 to October 1997.

Maier 2002: This was a blinded multicenter randomized placebo controlled study conducted in 14 centres in four European countries (Belgium, France, Germany, Switzerland) between May 1998 to June 1999. An early EPO, a late EPO and a control group were studied. The early EPO and late EPO groups were eligible for inclusion in this review.

Methodological quality of included studies

Both included studies (Donato 2000; Maier 2002) were randomized double-blind controlled studies with concealed allocation. Donato et al. (Donato 2000) report that infants were assigned to one of the two groups at birth through a central randomization process. Placebo and EPO were indistinguishable before and after reconstitution. Parents, investigators, and nurses were unaware of each patient's treatment group. Maier et al. (Maier 2002) concealed the allocation by means of numbered sealed envelopes. To assure blinding and to avoid placebo injections, sham injections were given to the late EPO group prior to starting treatment with EPO. In both studies, outcomes were assessed by individuals unaware of treatment assignment. Sample size calculations were performed in both studies. Six infants with significant protocol violations were excluded from the study by Donato et al. (Donato 2000). The group assignment was not reported, but it is likely that the excluded infants were equally distributed between the groups as 57 infants remained in each group. In the study by Maier et al (Maier 2002), no infant was withdrawn from the early EPO and late EPO groups. Followup was complete for the study by Maier (Maier 2002), but not in the study by Donato (Donato 2000). (See Table "Characteristics of included studies"). Both studies were industry funded (Donato 2000; Maier 2002). We obtained unpublished data from the authors of both studies.

Results

PRIMARY OUTCOME:

Comparison 01: Early (0-7 days) vs. late (8-28 days) initiation of EPO

Outcome 01.01: Use of one or more red blood cell transfusions

Both studies reporting on 262 infants assessed the use of one or more red blood cell transfusions. Neither found a significant effect. The meta-analysis did not find a significant effect [typical RR 0.91 (95% CI 0.78, 1.06); typical RD -0.07 (95% CI -0.18, 0.04)]. This result was consistent across studies.

SECONDARY OUTCOMES:

Outcome 01.02: The total volume (ml/kg) of red blood cells transfused per infant

Donato et al (Donato 2000) reported on this outcome in 144 infants. They did not find a significant effect [MD 30 ml/kg (95% CI -13.4, 13.6)].
We obtained unpublished data from Maier et al. (Maier 2002). They reported on the volume of red blood cells transfused in ml/kg/day. They did not find a significant effect [MD -0.80 ml/kg/day (95% CI -1.88, 0.28)].

Outcome 01.03: Number of red blood cell transfusions per infant

Both studies reporting on 262 infants assessed the number of red blood cell transfusions per infant. Neither found a significant effect. The meta-analysis did not find a significant effect [typical WMD -0.32, 95% CI -0.92, 0.29)]. This result was consistent across studies.

Outcome 01.04: Number of donors to whom the infant was exposed

Maier (Maier 2002) reported on this outcome in 148 infants. They did not find a significant effect [MD -0.20; (95% CI -0.67, 0.27)].

Outcome 01.05: Mortality during initial hospital stay (all causes)

Both studies reporting on 262 infants assessed mortality during initial hospital stay. Neither found a significant effect. The meta-analysis did not find a significant effect [typical RR 0.76 (95% CI 0.39, 1.51); RD - 0.03, (95% CI -0.11, 0.05)]. This result was consistent across studies.

Outcome 01.06: Retinopathy of prematurity (all stages)

We obtained unpublished data from both lead authors of the studies included in this review for this outcome. Both studies assessed retinopathy of prematurity in a total of 191 infants. Donato et al reported on the rate of ROP in infants examined during the first year of life. Maier et al reported on the worst stage of ROP during the study. There was a significant increase in the incidence of ROP (all stages) in the study by Donato et al (Donato 2000), but not in the study by Maier et al (Maier 2002). The meta-analysis found a significant effect [typical RR 1.40 (95% CI 1.05, 1.86); typical RD 0.16 (95% CI 0.03 0.29); NNTH; 6 (95% CI 3, 33)].There was statistically significant heterogeneity for this outcome (RR p = 0.007; I2 = 86%; RD p = 0.02; I2 = 81%).

Outcome 01.07: Retinopathy of prematurity (stage > 3)

We obtained unpublished data from both lead authors of the studies included in this review for this outcome. Both studies assessed this outcome in a total of 191 infants. Donato et al reported on the rate of ROP in infants examined during the first year of life. Maier et al reported on the worst stage of ROP during the study. Neither found a significant effect. The meta-analysis did not find a significant effect [typical RR 1.56 (95% CI 0.71, 3.41); typical RD 0.05 (95% CI -0.04, 0.14). This result was consistent across studies.

Proven sepsis (Clinical symptoms and signs of sepsis and positive blood culture) (No outcome table).

No data for this outcome were reported

Outcome 01.08 Necrotizing enterocolitis (NEC) (Bell's stage II or more)

Maier (Maier 2002) reported on this outcome in 148 infants. The study did not find a significant effect [RR 1.00 (95% CI 0.37, 2.71); RD 0.00 (95% CI -0.09, 0.09)].

Outcome 01.09: Intraventricular haemorrhage (IVH); all grades and grades III and IV

Both studies (n = 262) reported on the incidence of IVH grade III and IV. Neither found a significant effect. The meta-analysis did not find a significant effect [typical RR 1.33 (95% CI 0.84, 2.13); typical RD 0.06 (95% CI -0.04, 0.16)]. The results were consistent across studies.

Outcome 01.10: Periventricular leukomalacia (PVL); cystic changes in the periventricular areas

Maier (Maier 2002) reported on PVL in 148 infants. The study did not find a significant effect [RR 0.09 (95% CI 0.01, 1.62); RD -0.07 (95% CI -0.13, -0.01)].

Length of hospital stay (No outcome table)

Maier (Maier 2002) reported on the length of hospital stay. The median (quartiles) number of days in hospital was 87 days (73, 107) in the early EPO group and 90 days (68, 110) in the late group. There was no statistically significant difference (p = 0.94) across three groups including a control group (87 days; 69, 108).

Outcome 01.11: Bronchopulmonary dysplasia (BPD) (supplementary oxygen at 28 days of age or at 36 weeks postmenstrual age and compatible X-ray)

Maier (Maier 2002) reported on the need for oxygen at 36 weeks postmenstrual age in 148 infants. The study did not find a significant effect [RR 0.90 (95% CI 0.53, 1.54); RD -0.03 (95% -0.17, 0.12).

Outcome 01.12: Sudden infant death after discharge

Donato (Donato 2000) reported no deaths in either group after a follow-up period of 9 - 24 months after discharge.

Long term outcomes assessed at any age beyond one year of age by a validated cognitive, motor, language, or behavioural/school/social interaction/adaptation test (No outcome table).

No data for these outcomes were reported.

Neutropenia (No outcome table)

Donato (Donato 2000) reported that the incidence of neutropenia was similar in the two groups, but did not provide any data. Maier (Maier 2002) reported that neutrophil counts did not differ between groups, but did not provide any data.

Any side effects reported in the trials (No outcome table)

Donato (Donato 2000) stated "No clinical adverse effect attributable to EPO, oral iron, or folic acid administration was observed".

Outcome 01.13: Weight gain during the study period (This outcome was not included in the protocol for this review)

In the study by Donato (Donato 2000), the MD for weight gain during the entire study period was 6.0 g (95% CI -137.37, 149.37) comparing the early EPO group to the late EPO group. In the study by Maier (Maier 2002), the median weight gain was 890 g in the early EPO group and 872 g in the late EPO group during the first 9 weeks of life. Quartiles were not provided.

Outcome 01.14: Thrombocytosis (This outcome was not included in the protocol for this review)

Donato (Donato 2000) reported on thrombocytosis (platelet count > 500 x 109/L) in 114 infants. The study did not show a significant effect [RR 1.06 (95% CI 0.61, 1.84); RD 0.02 (95% CI -0.15, 0.19)].

In the study by Maier (Maier 2002) the median increase in platelet count during the study was 118 x 109/L in the early EPO group, 155x109/L in the late EPO group and 186 x 109/L in the control group. A p-value was not reported.

Subgroup analyses

We planned subgroup analyses within this review for low (< 500 IU/kg/week) and high (> 500 IU/kg/week) doses of EPO, and low (< 5 mg/kg/day) and high (> 5 mg/kg/day) doses of supplemental iron administered by any route. However, both included studies used high dose of EPO and high dose of iron, and therefore subgroup analyses were not performed.

Discussion

The main objective of this review was to assess whether early vs. late treatment with EPO would reduce the receipt of one or more red blood cell transfusions. Two high quality placebo controlled multicenter trials conducted in Argentina and in 4 European countries were identified for this review. These two studies included a total of 262 preterm infants with very low/extremely low birth weight, who were enrolled at approximately three days of age. The dose of EPO varied from 750 to 1250 IU/kg/week (high dose). All infants received supplemental iron (high dose). Both studies used well defined, although not identical, criteria for red blood cell transfusions (see Additional table; Table 01 Transfusion guidelines). In the study by Maier et al (Maier 2002), more than 30% of the enrolled infants had received red blood transfusions prior to study entry. In the study by Donato et al (Donato 2000), 14% had received red blood cell transfusions prior to enrolment.

Early treatment with EPO did not significantly reduce the risk for an infant of receiving a red blood cell transfusion compared to late treatment. There was no statistically significant heterogeneity for this or any of the other effectiveness outcomes of interest, justifying the combination of the results from the two studies when possible. There was no significant reduction in the number of transfusions per infant nor in the number of donors to whom the infant was exposed.

The results for other secondary outcomes included in this review reached statistical significance only for PVL and ROP. PVL was reported in one study (Maier 2002). There was a statistically significant reduction for RD but not for RR (there was no case of PVL in the early EPO group). We consider this finding of borderline statistical significance.

A total of 191 infants of 268 infants enrolled were assessed for ROP (all stages, and stage > 3). The lack of outcome ascertainment in a large number of infants is of concern. There was a statistically significant increased risk of ROP (any stage reported). The typical RR was 1.45 (95% CI 1.08, 1.95), the typical RD was 0.18 (95% CI 0.05, 0.31) and the NNTH was 6 (95% CI 3 -20). There was statistically significant heterogeneity for this outcome. The heterogeneity is likely at least in part due to differences in the rates of ROP and the different times in the life of the infants when ROP was assessed. There were no striking differences in the dose of EPO or iron used in the two studies. The transfusion guidelines were most strict in the study by Donato et al (Donato 2000). The outcome of ROP (stage > 3) was assessed in the same population as all stages of ROP. The meta-analysis did not find a significant effect [typical RR 1.56 (95% CI 0.71, 3.41); typical RD 0.05 (95% CI -0.04,0.14)]. This result was consistent across studies. The increased risk of ROP is of concern. The results are similar to the Cochrane review of "Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants" (Ohlsson 2006) No other important neonatal adverse outcomes or side effects were noted.

The results of this systematic review should be considered in conjunction with our other two Cochrane reviews that have been conducted "Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants" (Ohlsson 2006) and "Late erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants" (Aher 2006a). In our review of "Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants" (Ohlsson 2006), we noted an increased risk of ROP. Based on current evidence, an increased risk of developing ROP with early EPO cannot be excluded. For detailed discussion of the potential association with ROP and EPO, please refer to the Cochrane review of "Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants" (Ohlsson 2006).

Other systematic reviews of EPO do not address the issue of early vs. late treatment. The trials included in this review (Donato 2000; Maier 2002) were not included in the meta-analyses by Vamvakas et al (Vamvakas 2001) and Garcia et al (Garcia 2002). Kotto-Kome et al (Kotto-Kome 2004) included both trials in their meta-analysis of the effect of early EPO on early and late erythrocyte transfusions, but did not compare the effectiveness of early vs. late EPO administration. None of these meta-analyses included analyses on the incidence of ROP.

Early treatment with EPO did not confer any major benefits compared to late EPO treatment. The major obstacle to reduce any donor exposure during the hospital stay is that as many as one third of these infants will require a red blood cell transfusion prior to the initiation of treatment with EPO. In the study by Maier et al (Maier 2002), 12 of the 14 centers used satellite packs of the original red cell pack to reduce donor exposure in both groups. The use of satellite packs and conservative transfusion guidelines reduces the exposure to multiple donors during the hospitalization for preterm infants.

It is unlikely that long-acting EPO [Aranesp (Darbepopoietin alfa, Amgen)] would confer any benefits with regards to any donor exposure, but could reduce the number of injections the infant would require (Ohls 2004). To date, only a dose finding trial has been published (Warwood 2005). The authors concluded based on pharmacodynamic and pharmacokinetic findings that darbepoetin dosing in neonates would require a higher unit dose/kg and a shorter dosing interval than are generally used for anemic adults (Warwood 2005).

Reviewers' conclusions

Implications for practice

Currently there is lack of evidence that early EPO confers any substantial benefits compared to late administration of EPO, particularly with regard to any donor blood exposure, as a large proportion of infants enrolled in both studies were exposed to donor blood prior to study entry. There is a concern of an increased risk of ROP following early administration of EPO, and such treatment is not recommended.

Implications for research

The impact of either early or late administration of EPO on 'any donor exposure' is likely to be minimal, as many infants would have been exposed to donor blood during the first few days of life, when they are most likely to receive a red blood cell transfusion; a time period during which EPO treatment could not possibly prevent donor exposure. Any ongoing study of EPO should carefully monitor the incidence of ROP and data/safety monitoring committees should be informed of its occurrence. Further studies to compare early vs. late administration of EPO are not justified. Research should focus on reducing blood letting and the use of satellite packs from the same donor, should red blood cell transfusions be necessary.

Acknowledgements

We would like to thank Ms. Elizabeth Uleryk, Chief Librarian, the Hospital for Sick Children (SickKids,) Toronto, Ontario, Canada for developing the search strategy. We are thankful to Dr. Hugo Donato, Buenos Aires, Argentina, and to Dr. Rolf Maier, Zentrum für Kinder- und Jugendmedizin, Philipps-Universität, Marburg, Germany, who provided us with unpublished data regarding their studies.

Potential conflict of interest

None

Characteristics of included studies

Study Methods Participants Interventions Outcomes Notes Allocation concealment
Donato 2000 Randomized placebo controlled study
I. Blinding of randomization- yes
II. Blinding of intervention - yes
III. Blinding of outcome-measure assessment - yes
IV. Completeness follow-up - no (see notes)
 120 infants with BW < 1250 g and GA < 32 weeks were included
Exclusion criteria were: major congenital malformations, chromosomal anomalies, haemolytic and/or hemorrhagic disease, intrauterine infections, systemic hypertension, neutropenia
(no patient was excluded based on the severity of disease)
Recruitment period July 1996 to October 1997
7 private hospitals in Buenos Aires, Argentina
 Infants were randomized to two groups: In the early EPO group 57 infants (mean GA 27.7 wk +/- SD 2.4; mean BW 916 +/- SD 217) received rHuEPO (Hemax, Bio Sidus S.A, Buenos Aires, Argentina) [1250 IU/kg/week i.v. (high dose)] starting before 72 hours of life and until day 14 of life. In the late EPO group 57 infants (mean GA 27.9 weeks +/- SD 2.5; mean BW 972 +/- SD 206 received placebo (human seroalbumin) throughout this period. Starting on the third week of life, both groups received rHuEPO 750 IU/kg/week, divided in 3 doses s. c. during 6 weeks. All infants were given oral iron 6mg/kg/day as ferrous sulfate (high dose), starting as soon as enteral feedings were initiated and continuing during the entire treatment period Use of one or more red blood cell transfusions
Mean number of transfusions per infant
Mortality during hospital stay
Number of transfusions per patient
Volume of transfused blood per patient (ml/kg)
ROP (during initial study period and during the first year of life) (data obtained from the authors)
Weight gain during study period
Neutropenia
SIDS
Adverse effects
 Sample size calculation was performed
Transfusion guidelines were followed
6 infants (group not stated) with significant protocol violations were excluded
8 of 57 (14%) of patients in the early EPO group (mean number of transfusions 1.12; range 1-2) and 8 of 57 (14%) patients in the late EPO group (mean number of red blood cell transfusions 1.25; range 1-3) received red blood cell transfusions prior to study entry
This study received industry support (Bio Sidus S.A. Laboratory)		 A
Maier 2002 Randomized controlled study
I. Blinding of randomization - yes
II. Blinding of intervention - yes
III. Blinding of outcome-measure assessment - yes
IV. Completeness follow-up- yes		 148 infants with BW 500 - 999 g
Exclusion criteria: cyanotic heart disease, major congenital malformation requiring surgery, administration of investigational drug during pregnancy, gestational age >/= 30 completed weeks
Enrolment period May 1998 to June 1999
14 centres in 4 European countries (Belgium, France, Germany, Switzerland)		 Infants were randomized to 3 groups (see notes for the control group). In the early EPO group 74 infants [median and quartiles for GA; 26 (25, 28) weeks for BW 778 (660, 880) g] received 250 IU/kg of rHEPO on Mondays, Wednesdays and Fridays (NeoRecormon, F. Hofman-La Roche, Basel Switzerland) (750 IU/week, high dose) starting at days 3-5 of life.
In the late EPO group 74 infants received the same treatment 3 weeks later
Treatment in both groups continued until days 65 to 68 of life. rHEPO was given i.v. in both groups as long as the infant had an i.v. line in place and s. c. thereafter. The late EPO group received sham-injections until EPO was given.
Enteral iron 3mg/kg was given to all infants from days 3 to 5 (low dose) and was increased at days 12 to 14 to 6 mg/kg/day (high dose) and to 9mg/kg/day at days 24 to 26 of life (high dose), if transferrin saturation was < 30%. At transferrin saturation of 30 to 80%, the iron dose was kept at 6 mg/kg/day. At transferrin saturation > 80%, iron supplementation was interrupted.
Use of one or more red blood cell transfusions
Mortality during hospital stay
NEC
IVH
PVL
ROP
Days in oxygen
Days in NICU
Days in hospital		 Sample size calculation was performed
Transfusion guidelines were followed
24 (32%) of the infants in the early EPO group and 23 (31%) in the late EPO group received 1 to 3 transfusions before they entered the study.
A third group (control group, n =71) was included in this trial. This study (and this group) is included in the Cochrane reviews of early EPO vs. controls and late EPO vs. controls
Industry funded (F. Hoffman-La Roche, Basel Switzerland)		 A
BW = birth weight
GA = gestational age
g = grams
i.v. = intravenously
s.c. subcutaneously

Characteristics of excluded studies

Study Reason for exclusion
Rudzinska 2002 This was a controlled but not randomized study of early vs. late treatment with EPO in preterm infants with birth weights < 1500 g.

References to studies

References to included studies

Donato 2000 {published and unpublished data}

Donato H, Vain N, Rendo P, Vivas N, Prudent L, Larguia M, et al. Effect of early versus late administration of human recombinant erythropoietin on transfusion requirements in premature infants: results of a randomized, placebo-controlled, multicenter trial. Pediatrics 2000;105:1066-72.

Maier 2002 {published and unpublished data}

Maier RF, Obladen M, Muller-Hansen I, Kattner E, Merz U, Arlettaz R, et al. Early treatment with erythropoietin beta ameliorates anemia and reduces transfusion requirements in infants with birth weights below 1000 g. Journal of Pediatrics 2002;141:8-15.

References to excluded studies

Rudzinska 2002 {published data only}

Rudzinska IM, Kornacka MK, Pawluch R. Leczenie preparatami ludzkiej rekombinowanej erytropoetyny a czeztosc retinopatii u noworodkow przedwczesnie urodzonych (Polish) [Treatment with human recombinant erythropoietin and frequency of retinopathy of prematurity]. Prezglad Lekarski 2002;59 Supplement 1:83-5.

* indicates the primary reference for the study

Other references

Additional references

Aher 2006a

Aher S, Ohlsson A. Late erythropoietin for preventing red blood cell transfusion. In: The Cochrane Database of Systematic Reviews, Issue 3, 2006.

Brown 1983

Brown MS, Phibbs RH, Garcia JF, Dallman PR. Postnatal changes in erythropoietin levels in untransfused premature infants. Journal of Pediatrics 1983;103:612-7.

Dallman 1981

Dallman PR. Anemia of prematurity. Annual Review of Medicine 1981;32:143-60.

Dame 2001

Dame C, Juul SE, Christensen RD. The biology of eryhtropoietin in the central nervous system and its neutrophic and neuroprotective potential. Biology of the Neonate 2001;79:228-35.

Finch 1982

Finch CA. Erythropoiesis, erythropoietin and iron. Blood 1982;60:1241-6.

Garcia 2002

Garcia MG, Hutson AD, Christensen RD. Effect of recombinant erythropoietin on "late" transfusions in the neonatal intensive care unit: a meta-analysis. Journal of Perinatology 2002;22:108-11.

Genen 2004

Genen LH, Klenoff H. Iron supplementation for erythropoietin-treated preterm infants (Protocol). In: The Cochrane Database of Systematic Reviews, Issue 1, 2001.

Hesse 1997

Hesse L, Eberl W, Schlaud M, Poets CF. Blood transfusion. Iron load and retinopathy of prematurity. European Journal of Pediatrics 1997;156:465-70.

Juul 2002

Juul S. Erythropoietin in the central nervous system, and its use to prevent hypoxic-ischemic brain damage. Acta Paediatrica Supplement 2002;91:36-42.

Kling 2002

Kling PJ, Winzerling JJ. Iron status and the treatment of the anemia of prematurity. Clinics in Perinatology 2002;29:283-94.

Kotto-Kome 2004

Kotto-Kome AC, Garcia MG, Calhoun DA, Christensen RD. Effect of beginning recombinant erythropoietin treatment within the first week of life, among very-low-birth-weight neonates, on "early" and "late" erythrocyte transfusions: a meta-analysis. Journal of Perinatology 2004;24:24-9.

Ohls 2000

Ohls RK. The use of erythropoietin in neonates. Clinics in Perinatology 2000;27:681-96.

Ohls 2002

Ohls RK. Erythropoietin treatment in extremely low birth weight infants: blood in versus blood out. Journal of Pediatrics 2002;141:3-6.

Ohls 2004

Ohls RK, Dai A. Long-acting erythropoietin: cllinical studies and potential uses in neonates. Clinics in Perinatology 2004;31:77-89.

Ohlsson 2006

Ohlsson A, Aher SM. Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants. In: The Cochrane Database of Systematic Reviews, Issue 3, 2006.

Shannon 1995

Shannon KM, Keith JF 3rd, Mentzer WC, Ehrenkranz RA, Brown MS, Widness JA et al. Recombinant human erythropoietin stimulates erythropoiesis and reduces erythrocyte transfusions in very low birth weight infants. Pediatrics 1995;95:1-8.

Stockman 1978

Stockman JA 3rd, Oski FA. Physiological anaemia of infancy and the anaemia of prematurity. Clinics in Hematology 1978;7:3-18.

Stockman 1986

Stockman JA 3rd. Anemia of prematurity. Current concept in the issue of when to transfuse. Pediatric Clinics of North America 1986;33:111-28.

Strauss 1986

Strauss RG. Current issues in neonatal transfusions. Vox Sanguinis 1986;51:1-9.

Vamvakas 2001

Vamvakas EC, Strauss RG. Meta-analysis of controlled clinical trials studying the efficacy of rHuEPO in reducing blood transfusions in the anemia of prematurity. Transfusion 2001;41:406-15.

Warwood 2005

Warwood TL, Ohls RK, Wiedmeier SE, Lambert DK, Jones C, Scoffield SH et al.. Single-dose darbepoetin administration to anemic preterm neonates. Journal of Perinatology 2005;25:725-30.

Widness 1991

Widness JA, Sawyer RL, Schmidt RL, Chestnut DH. Lack of maternal to fetal transfer of 125I-labelled erythropoietin in sheep. Journal of Developmental Physiology 1991;15:139-45.

Widness 1996

Widness JA, Seward VJ, Kromer IJ, Burmeiser LF, Bell EF. Changing patterns of red blood cell transfusion in very low birth weight infants. Journal of Pediatrics 1996;129:680-7.

Zanjani 1981

Zanjani ED, Ascensao JL, McGlave PB, Banisadre M, Ash RC. Studies on the liver to kidney switch of erythropoietin production. Journal of Clinical Investigation 1981;67:1183-8.

Zipursky 2000

Zipursky A. Erythropoietin therapy for premature infants: cost without benefit? Pediatric Research 2000;48:136.

Comparisons and data

Comparison or outcome Studies Participants Statistical method Effect size
01 Early (0-7 days) vs. late (8-28 days) initiation of EPO
01 Use of one or more red blood cell transfusions 2 262 RR (fixed), 95% CI 0.91 [0.78, 1.06]
02 Total volume of red blood cells transfused per infant     WMD (fixed), 95% CI Subtotals only
03 Number of red blood cell transfusions per infant 2 262 WMD (fixed), 95% CI -0.32 [-0.92, 0.29]
04 Number of donors the infant was exposed to 1 148 WMD (fixed), 95% CI -0.20 [-0.67, 0.27]
05 Mortality during initial hospital stay (all causes) 2 262 RR (fixed), 95% CI 0.76 [0.39, 1.51]
06 Retinopathy of prematurity (all stages) 2 191 RR (fixed), 95% CI 1.40 [1.05, 1.86]
07 Retinopathy of prematurity (stage >/= 3) 2 191 RR (fixed), 95% CI 1.56 [0.71, 3.41]
08 NEC 1 148 RR (fixed), 95% CI 1.00 [0.37, 2.71]
09 IVH 2 262 RR (fixed), 95% CI 1.33 [0.84, 2.13]
10 PVL 1 148 RR (fixed), 95% CI 0.09 [0.01, 1.62]
11 BPD (oxygen at 36 weeks) 1 148 RR (fixed), 95% CI 0.90 [0.53, 1.54]
12 Sudden infant death after discharge 1 114 RR (fixed), 95% CI Not estimable
13 Weight gain (grams) during the study period (from entry to exit from study) 1 114 WMD (fixed), 95% CI 6.00 [-137.37, 149.37]
14 Thrombocytosis (platelet count > 500 x 10 to the 9th /L) 1 114 RR (fixed), 95% CI 1.06 [0.61, 1.84]

01 Early (0-7 days) vs. late (8-28 days) initiation of EPO

01.01 Use of one or more red blood cell transfusions

01.02 Total volume of red blood cells transfused per infant

01.02.01 Total volume of red blood cells transfused (ml/kg)

01.02.02 Total volume of red cells transfused (ml/kg/day)

01.03 Number of red blood cell transfusions per infant

01.04 Number of donors the infant was exposed to

01.05 Mortality during initial hospital stay (all causes)

01.06 Retinopathy of prematurity (all stages)

01.07 Retinopathy of prematurity (stage >/= 3)

01.08 NEC

01.09 IVH

01.09.01 Grade III/IV

01.10 PVL

01.11 BPD (oxygen at 36 weeks)

01.12 Sudden infant death after discharge

01.13 Weight gain (grams) during the study period (from entry to exit from study)

01.14 Thrombocytosis (platelet count > 500 x 10 to the 9th /L)

Additional tables

01 Transfusion guidelines

Reference Indications
Donato 2000 Indications for transfusion followed slightly modified criteria described in a previous study (Shannon 1995). The transfusion criteria were: A) Hct 0.31-0.35; Receiving >35% supplemental hood oxygen; Intubated on CPAP or mechanical ventilation with mean airway pressure >6-8 cm water B) Hct 0.21-0.30; Receiving <35% supplemental hood oxygen; On CPAP or mechanical ventilation with mean airway pressure <6 cm water; Significant apnea and bradycardia (>9 episodes in 12 hours or 2 episodes in 24 hours requiring bag and mask ventilation) while receiving therapeutic doses of methylxanthines; Heart rate >180 beats/min or respiratory rate >80 breaths/min persisting for 24 hours; Weight gain <10 g/day observed over 4 days while receiving >100 kcal/kg/day; Undergoing surgery C) Hct <21%; Asymptomatic with reticulocytes <1% D) Transfuse at any hematocrit value if hypovolemic shock develops E) Do not transfuse: to replace blood removed for laboratory tests; For low Hct alone. Patients were transfused with packed red blood cells at 15 ml/kg, administered in 2-3 hours.
Maier 2002 Infants on assisted ventilation or > 40% of inspired oxygen were not transfused unless Hct dropped below 0.40. Spontaneously breathing infants were not transfused unless Hct dropped below 0.35 during the first 2 weeks of life, 0.30 during the 3rd to 4th weeks, and 0.25 thereafter. Transfusion was allowed when life threatening anaemia or hypovolaemia was diagnosed by the treating neonatologist, or surgery was planned. Twelve of the 14 centres used satellite packs of the original red cell pack to reduce donor exposure. The amount of packed red cells transfused was not reported.

Contact details for co-reviewers

Dr Arne Ohlsson
Director Evidence Based Neonatal Care and Outcomes Research
Department of Paediatrics
Mount Sinai Hospital
600 University Avenue
Toronto
Ontario CANADA
M5G 1X5
Telephone 1: +1 416 586 8379
Telephone 2: +1 416 341 0444
Facsimile: +1 416 586 8745
E-mail: aohlsson@mtsinai.on.ca

This review is published as a Cochrane review in The Cochrane Library, Issue 3, 2006 (see http://www.thecochranelibrary.com for information).  Cochrane reviews are regularly updated as new evidence emerges and in response to feedback.  The Cochrane Library should be consulted for the most recent version of the review.