The annual mortality rate for patients with end-stage renal disease (ESRD) is 20 percent, with a 5-year survival rate of about 29 percent for patients undergoing renal dialysis. The highest risk of dying occurs during the first year of renal dialysis. Although early nephrologist evaluation is associated with better patient outcomes, 25 percent of ESRD patients first see a nephrologist only a month before beginning dialysis.
ESRD patients who consult with a nephrologist more than 3 months before beginning dialysis, and who see that specialist more often, are less likely to die during the first year of dialysis, according to a study supported in part by the Agency for Healthcare Research and Quality (HS09398). A second AHRQ-supported study (HS08365) shows that late evaluation of ESRD patients by a nephrologist is associated with shorter survival time, as are coexisting disease, black ethnicity, and lack of health insurance. These two studies are described here.
Avorn, J., Bohn, R.L., Levy, E., and others (2002, September). "Nephrologist care and mortality in patients with chronic renal insufficiency." Archives of Internal Medicine 162, pp. 2002-2006.
In this largest study to date of predialysis patients, the researchers identified all patients in the New Jersey Medicaid and Medicare programs who began maintenance dialysis during a 6-year period and had been diagnosed with renal disease more than 1 year prior to dialysis. They documented use of nephrologist services during the year prior to the start of dialysis, along with other clinical and sociodemographic variables and mortality during the first year of dialysis.
Patients who did not see a nephrologist until 90 days or less before they began dialysis (late referral) were 37 percent more likely to die in the first year of dialysis than patients referred to a nephrologist earlier. Similarly, those who visited a nephrologist fewer than five times in the year prior to dialysis were 15 percent more likely to die in the first year of dialysis compared with those who had five or more visits. Socioeconomic status did not appear to affect timing of nephrologist referral, since Medicaid and Medicare patients had no greater risk of death than more affluent patients, after adjusting for other factors.
However, use of nephrologists may correlate with other issues of access and quality of care, which themselves may play an important role in outcomes. For example, patients who are referred to a nephrologist may have a primary care physician who is also more conscientious about managing other aspects of their care, such as hypertension or nutrition. Alternatively, patients referred to nephrologists are more likely to be treated with erythropoietin for anemia, possibly lowering the risk of death, or to have a permanent vascular access created for maintenance dialysis, especially a primary fistula (opening surgically created from one's own skin). This, in turn, may reduce the risk of infections during renal replacement therapy and/or improve dialysis doses. The investigators suggest that these findings be confirmed in younger and less indigent patients.
Kinchen, K.S., Sadler, J., Fink, N., and others (2002, September). "The timing of specialist evaluation in chronic kidney disease and mortality." Annals of Internal Medicine 137, pp. 479-486.
The later a patient with ESRD is evaluated by a nephrologist, the greater the risk of death, especially for black patients and those who have diabetes, conclude these researchers. They prospectively studied 828 patients with new-onset ESRD treated at 81 dialysis facilities throughout the United States and calculated time from first evaluation by a nephrologist to initiation of dialysis. They classified evaluations done less than 4 months prior to dialysis as late, 4 to 12 months prior to dialysis as intermediate, and over 12 months as early. They examined rate of death from initiation of dialysis to an average of 2.2 years later.
After adjustment for potential confounding factors, late evaluation was more common among black men than white men (45 vs. 25 percent), uninsured patients than insured patients (57 vs. 29 percent), and patients with severe rather than mild coexisting disease (35 vs. 23 percent). Compared with patients who were evaluated early, the risk for death was 30 percent and 80 percent greater, respectively, among patients with intermediate or late evaluation, after adjustment for dialysis method, demographic characteristics, and socioeconomic status. After further adjustment for factors such as the presence and severity of coexisting medical problems, patients with intermediate or late referral still had a higher risk of dying than patients referred early.
Late referral could be due to asymptomatic renal failure in ESRD, noncompliance with referrals, lack of access to any medical care, or attitudes of primary care doctors about referral of ESRD patients to specialists. Clinicians need a system to remind them to refer patients to nephrologists when they are at an early stage of chronic renal failure, especially black men, the uninsured, and patients with severe coexisting illness. New practice guidelines for the treatment of chronic kidney disease define at what glomerular filtration rate (an indicator of kidney functioning) a patient should be referred to a nephrologist.
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