Diagnosis and Treatment of Swallowing Disorders (Dysphagia) in Acute-Care Stroke Patients

THIS EVIDENCE REPORT IS OUTDATED AND IS NO LONGER VIEWED AS GUIDANCE FOR CURRENT MEDICAL PRACTICE. IT IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY.

U.S. Department of Health and Human Services
2101 East Jefferson Street
Rockville, MD 20852
http://www.ahcpr.gov

The Agency for Health Care Policy and Research (AHCPR), through its Evidence-based Practice Centers (EPCs), sponsors the development of evidence reports and technology assessments to assist public- and private-sector organizations in their efforts to improve the quality of health care in the United States. The reports and assessments provide organizations with comprehensive, science-based information on common, costly medical conditions and new health care technologies. The EPCs systematically review the relevant scientific literature on topics assigned to them by AHCPR and conduct additional analyses when appropriate prior to developing their reports and assessments.

To bring the broadest range of experts into the development of evidence reports and health technology assessments, AHCPR encourages the EPCs to form partnerships and enter into collaborations with other medical and research organizations. The EPCs work with these partner organizations to ensure that the evidence reports and technology assessments they produce will become building blocks for health care quality improvement projects throughout the Nation. The reports undergo peer review prior to their release.

AHCPR expects that the EPC evidence reports and technology assessments will inform individual health plans, providers, and purchasers as well as the health care system as a whole by providing important information to help improve health care quality.

We welcome written comments on this evidence report. They may be sent to: Director, Center for Practice and Technology Assessment, Agency for Health Care Policy and Research, 6010 Executive Blvd., Suite 300, Rockville, MD 20852.



John M. Eisenberg, M.D.	Douglas B. Kamerow, M.D.
Administrator	Director, Center for Practice and Technology Assessment
Agency for Health Care Policy and Research	Agency for Health Care Policy and Research

The authors of this report are responsible for its content. Statements in the report should not be construed as endorsement by the Agency for Health Care Policy and Research or the U.S. Department of Health and Human Services of a particular drug, device, test, treatment, or other clinical service.

This report was requested by the Health Care Financing Administration, which sought an evidence-based assessment of methods for diagnosing and treating swallowing disorders (dysphagia) in elderly individuals with neurologic diseases, and specifically those methods associated with the services provided by speech-language pathologists. About 6,228,000 Americans over age 60 have dysphagia, and about 300,000 to 600,000 people are affected by dysphagia resulting from neurologic disorders each year.

This report addresses four questions: (1) How does diagnosis of dysphagia or aspiration affect treatment courses and patient outcomes? (2) What are the indications for diagnosing patients using a full bedside exam (BSE), modified barium swallow, fiberoptic endoscopy, or other instrumented exams? (3) Is one diagnostic technology more effective than any other? and (4) When is noninvasive therapy appropriate, and when should feeding tubes be used in certain patient populations?

We used broad-based literature searching to ensure that we found all relevant information. Thus, we searched 23 electronic databases, including MEDLINE and Embase. Search terms included those relevant to the disorder, diagnostics, epidemiology, etiology, and treatment of dysphagia. Search dates depended on the database, but ranged from 1945 to July 1998. We also searched 23 World Wide Web sites, conducted hand searches of article bibliographies, and sought published and unpublished information from experts in the field.

We adopted broad criteria to ensure retrieval of all relevant information. Articles were retrieved if they were clinical studies of any design containing information derived from 10 or more patients. Two researchers independently requested articles. Disputes were resolved in favor of obtaining the article.

Data from clinical trials on diagnostic test performance and/or patient outcomes were entered directly into evidence tables. This information included study size, design, diagnostic method(s), patient selection criteria and characteristics, and patient outcomes.

Studies were separated by their design, but their quality was not necessarily ranked according to it. We did not rigidly adhere to a formal quality ranking scheme because some randomized controlled trials (RCTs) had flaws serious enough to render their results unreliable. Similarly, we did not always consider case-controlled studies to provide more reliable information than case series because of certain flaws in the former.

To reach our conclusions, we performed two cost-effective analyses, a meta-analysis of the efficacy of the 3-ounce water test, a similar meta-analysis of the BSE, an exploratory meta-analysis (so called because the control data were derived from historical sources) on the effects of dysphagia diagnosis and treatment programs on patient outcomes, an illustrative meta-analysis that addresses the technical issue of the low statistical power of vote-counting procedures, and numerous other quantitative analyses. The need to perform these original calculations is a reflection on the relatively poor reporting in this literature.

We focused on dysphagia diagnosis and treatment programs because assessment of dysphagia diagnosis and treatment independent of one another provides only limited information. The emphasis of our analysis was on stroke victims, which reflects the preponderance of the literature. Stroke victims also comprise the largest group of patients with neurologic disease who have dysphagia. Outcomes of particular interest were aspiration pneumonia, malnutrition, dehydration, and quality of life (QOL), but the most data were available for aspiration pneumonia.

The evidence regarding the first question, which is the most significant of our key questions, suggests that dramatic reductions in the occurrence of pneumonia are observed when a systematic program of diagnosis and treatment of dysphagia in an acute stroke management plan is implemented. Because these data are from historically controlled studies rather than RCTs (which may be unethical in this context), the exact magnitude of this reduction in pneumonia rates is difficult to determine. Also for this reason, it is equally difficult to determine the contribution of the dysphagia-specific aspects of the management programs to these rate reductions (as opposed to those aspects of the stroke management program not related to diagnosis and treatment of dysphagia). However, because the effects observed in these studies are substantial, it would be imprudent to ignore them. Therefore, these results must be taken as evidence of efficacy of these programs. Malnutrition, dehydration, and QOL were not addressed in available studies.

Regarding the second question, the risk for developing aspiration pneumonia cannot be accurately predicted from any single clinical sign or symptom. There is a clear-cut need to optimize a brief initial exam that employs several key signs and symptoms to accurately detect patients with possible unsafe swallows and who therefore need more extensive testing.

The results of the studies of diagnostic test performance that address the third question are erroneous because treatment necessarily follows diagnosis of a swallowing disorder. This treatment makes it impossible to distinguish between the true- and false-positive results of these tests. Because of this, the purely diagnostic abilities of the various tests cannot be determined; thus, the tests can only be compared by assessing how they direct treatment and influence adverse patient outcomes, as addressed in our first question above.

We constructed two cost-effectiveness models to address this issue, and their results suggest that use of the full BSE in dysphagia programs reduces costs. These models, which are based on published protocols and findings, assume that patients will receive a preliminary bedside assessment, and that one result of this assessment is that no more than about 39 percent of patients will be referred for further evaluation, as occurred in the best study we evaluated. Under these conditions, our cost-effectiveness analysis suggests that dysphagia diagnosis and treatment programs that employ the full BSE would either save money or have very little net cost if they reduced pneumonia rates by amounts similar to those obtained in certain published studies. In addition, our results indicate that the slightly higher costs of videofluoroscopy would be offset if it provided slightly less than an additional 10 percent reduction in pneumonia rates, again assuming that no more than about 39 percent of patients are referred for videofluoroscopy or the full BSE.

Evidence related to the fourth question consists of limited data from a single RCT concluding that a soft mechanical diet including thickened liquids results in lower morbidity than does a pureed diet. Although numerous other studies have been conducted on dysphagia treatments, their designs make it impossible to assess the efficacy of individual treatments. A single RCT with low statistical power reported inconclusive results about the effect of treatment intensity level on patient outcomes.

A well-designed trial that compares dysphagia management programs using different diagnostic modalities is needed. This trial should take into account the current lack of a demonstrated gold standard diagnostic test, have acceptable statistical power, and consider the fact that treatment of patients distorts measures of diagnostic test performance. Because of this urgent need, we provide a detailed description of the design and analysis of a trial that would answer several major unanswered questions.

Available evidence on the diagnosis and treatment of dysphagia is extremely limited. Nevertheless, current data suggest that implementation of dysphagia management programs for stroke patients in the acute-care setting is accompanied by a reduction in pneumonia rates. Use of the full BSE in these programs appears to be cost-effective. The limitations of available evidence do not allow us to determine the extent to which videofluoroscopy or fiberoptic endoscopy reduce pneumonia rates compared with the full BSE despite the fact that it is reasonable to believe the additional information they provide would lead to improved patient outcomes. Although the added benefits provided by instrumented exams are likely to be small, videofluoroscopy may be cost-effective if used in programs in which no more than about 39 percent of all patients are referred to this test, and if its use leads to an additional 10 percent reduction in pneumonia rates, compared with the full BSE. There is a clear-cut need to optimize a brief initial exam that accurately detects patients with possible unsafe swallows who may therefore need more extensive testing. Study designs used in the evaluation of noninvasive therapy have made it impossible to assess the efficacy of individual treatments. However, there is evidence supporting the use of a soft mechanical diet over a pureed diet for preventing aspiration pneumonia in stroke patients with dysphagia who have a history of aspiration pneumonia. The evidence on whether treatment that is more intensive yields better patient outcomes than less intensive treatments is inconclusive. Well-designed studies, particularly those that compare diagnostic modalities, are needed.

This document is in the public domain and may be used and reprinted without permission, except for those copyrighted materials noted for which further reproduction is prohibited without specific permission of copyright holders.

Diagnosis and Treatment of Swallowing Disorders (Dysphagia) in Acute-Care Stroke Patients. Evidence Report/Technology Assessment No. 8. (Prepared by ECRI Evidence-based Practice Center under Contract No. 290-97-0020.) AHCPR Publication No. 99-E024. Rockville, MD: Agency for Health Care Policy and Research. July 1999.

This report has two goals: (1) to examine, in an evidence-based fashion, the efficacy and cost-effectiveness of methods for diagnosing and treating swallowing disorders in elderly individuals with neurologic disorders, and (2) to suggest important directions for future dysphagia research.

In addressing the first goal, we concentrate on the broad area of speech-language pathology and, more specifically, on the diagnostic and treatment methodologies associated with the services provided by speech-language pathologists. Services provided by gastroenterologists or other medical professionals are not emphasized. Partly because of this, we focus on oropharyngeal dysphagia and do not consider esophageal dysphagia to any great extent. Thus, those services provided to cancer patients, patients who have undergone esophageal surgery, or patients with esophageal reflux are not discussed here.

The available evidence further defined the scope of this report. We attempted to address all neurologic disorders that affect the elderly and that commonly cause dysphagia. However, the preponderance of published data focuses on stroke victims, making this, by necessity, the focus of this report. This restriction is not severe because most cases of dysphagia occur in these patients. However, it does mean that we focus on the diagnosis and treatment of dysphagia in a patient population that contains some patients who may ultimately spontaneously recover their swallowing function and we do not focus on patients with neurodegenerative diseases, whose swallowing function may progressively worsen.

In addressing the second goal of this report, we offer detailed recommendations for conducting a clinical trial. To make the reasons for the details of this trial clear, we comment throughout this report on the strengths and weaknesses of available studies. In doing so, we develop two major themes. The first is that in many studies on diagnostic tests for dysphagia, there is a relationship between diagnosis and treatment that makes it impossible to distinguish between the true- and false-positive results of these tests in terms of predicting risk for pneumonia (by detection of aspiration). Successful treatment will turn some true positives for pneumonia risk into apparent false positives. This, in turn, means that the diagnostic test sensitivities and specificities for pneumonia risk reported in many studies are incorrect, and the true values cannot be known without unethically withholding treatment from some patients diagnosed with dysphagia and aspiration. Because these true values cannot be known, it is not possible to compare tests on the basis of these values. Thus, the only ethical way to compare diagnostic tests is to compare the patient outcome of prevention of pneumonia following diagnosis and treatment, not the sensitivities and specificities for detection of pneumonia risk. In such comparisons of pneumonia outcomes it must be ensured that patients given different diagnostic tests receive similar treatment.

The second theme we develop is one of statistical power. Virtually all of the studies in this area that attempt to compare the efficacy of diagnostic tests or treatment are too small. In general, they contain no more than 150 patients when 10 times this many are needed to obtain statistically significant differences.

Dysphagia is commonly associated with several neurologic disorders. Oropharyngeal dysphagia can be quite serious if it results in leakage of food, drink, or oral secretions into the lungs (aspiration); this can lead to aspiration pneumonia. Aspiration pneumonia can be fatal, and the elderly are at particular risk for death. Dysphagia can also be serious if the patient is unable to eat enough food to maintain a healthy weight. Malnutrition may occur if the problem is not diagnosed correctly, and malnutrition in turn can weaken the immune system, leaving the patient susceptible to illness. Finally, patients with dysphagia may suffer from dehydration and have a reduced quality of life (QOL).

Information on the incidence and prevalence of dysphagia is sparse. To estimate the incidence of dysphagia and consider the impact of this disease on society, we performed 99 original calculations based on existing data. From these calculations, we estimate that approximately 300,000 to 600,000 people per year are affected by dysphagia resulting from neurologic disorders. Only about 51,000 of these cases are from neurologic disorders other than stroke. On the basis of data from the stroke literature, we estimate that approximately 43 percent to 54 percent of stroke patients with dysphagia experience aspiration, approximately 37 percent of these patients will develop pneumonia, and 3.8 percent of these will die of pneumonia if they are not part of a dysphagia diagnosis and treatment program. Up to 48 percent of all acute-care stroke patients with dysphagia will experience malnutrition.

Formal diagnosis of oropharyngeal dysphagia is commonly carried out using a full bedside exam (BSE) or videofluoroscopy (also called the modified barium swallow, or MBS), but other diagnostic methods are available, including several variants of fiberoptic endoscopy. Common treatments include both noninvasive therapies (such as diet modification and swallow therapy) and invasive therapies such as percutaneous endoscopic gastrostomy (PEG). PEG is the most common invasive intervention for neurogenic oropharyngeal dysphagia, and is often used when dysphagia and aspiration are serious enough to be life threatening.

In examining the efficacy and cost-effectiveness of methods for diagnosing and treating dysphagia, we address four key questions:

1. How does diagnosis of dysphagia or aspiration affect the subsequent course of treatment and outcomes?

2. What are the appropriate indications for having patients diagnosed using a full BSE, the MBS, fiberoptic endoscopy, or another instrumented exam?

3. Is there any evidence that one diagnostic technology provides more useful information than any other diagnostic?

4. When is noninvasive swallow therapy appropriate? Does it work particularly well or particularly poorly in any particular patient population? What can the evidence tell us about this therapy? Are feeding tubes useful or a last resort that might be avoided for some patients by dysphagia diagnosis and therapy?

We ranked each of these questions according to their presumed significance to patients and society using a six-level hierarchy. Thus, questions with the greatest significance are more general and encompass the patient outcomes obtained using the combination of dysphagia diagnosis and treatment, a combination that mirrors actual clinical practice. Those questions with presumably lesser significance focus either on treatment alone or only on diagnostic efficacy.

According to this hierarchy, Question 1 has the greatest significance to patients and society because it directly addresses the benefits that accrue to patients as a result of dysphagia diagnosis and treatment. Neither Questions 2 nor 3 specifically address treatment, and Question 4 does not consider the benefits that may accrue to patients as a result of diagnosing dysphagia.

Despite the relative importance of these four questions, we devote considerable effort to determining the relative efficacy of different diagnostic tests because patients afforded the most efficacious test are the most likely to benefit the most. Of primary interest in our assessment, therefore, were the efficacies of the commonly used instrumented and noninstrumented technologies. Instrumented tests include the videofluoroscopic swallow study (VFSS), the primary variant of which, in this field, is the MBS. Investigators in dysphagia research consider the MBS the gold standard against which to compare new diagnostic technologies. Also of particular interest were two newer technologies: the fiberoptic endoscopic exam of swallowing (FEES) and the fiberoptic endoscopic exam of swallowing with sensory testing (FEESST).

The noninstrumented diagnostic test of primary interest in this report is the full BSE. This is a formal, structured test that often incorporates a questionnaire, noninvasive oral-pharyngeal physical examination, and functional swallowing tests. There are many variants of this diagnostic test, and sometimes it consists of only of a simple water swallow test. To avoid confusion of this exam with a preliminary BSE, which also has many variants, we refer to the formal, structured exam as the full BSE.

The focus of our analysis of these diagnostic tests, which is again dictated by the preponderance of the literature, is on the ability of these tests to predict aspiration and aspiration pneumonia. We were, however, interested in all patient outcomes, including mortality and any morbidity directly associated with dysphagia or aspiration. These include pneumonia, malnutrition, dehydration, QOL, feeding tube complications, and death, and short-term outcomes such as energy intake, weight change, and successful feeding levels. We examine these to the extent that the literature will allow.

The treatments on which we focused were primarily noninvasive; however, minimally invasive therapy, PEG, was also considered because some patients may have severe dysphagia that precludes oral feeding. There are two basic categories of noninvasive treatment: swallow therapy and diet modification. Within the category of swallow therapy are three basic subcategories: compensatory techniques (which teach the patient postural maneuvers to compensate for swallowing difficulty or provide more sensory information to the patient through changes in bolus characteristics), indirect swallow therapy (which serves to teach the patient exercises to strengthen impaired or weakened muscles), and direct swallow therapy (in which patients are taught exercises to perform during the swallow to force the bolus to pass through the pharynx correctly).

Diet modification is sometimes used if the patient aspirates only certain substances while swallowing. This modification is individualized to the patient's needs, depending on the viscosity or volume of the boluses aspirated. Most patients who aspirate because of neurogenic dysphagia aspirate thin liquids, so patients are often put on a diet in which liquids are thickened, usually with a commercial thickening agent. Less common is difficulty with solids, but if a patient were to experience this, solid food would be pureed before it is eaten.

We searched 23 electronic databases both to retrieve clinical trials for analysis and to review articles to gauge current opinion in the field. The databases searched and general keywords used are listed below:

The Database of Reviews of Effectiveness (Cochrane Library) (through 1998 Issue 3)

ECRI International Health Technology Assessment (IHTA) Database (1990 through July 1998)

Health Care Financing Administration (HCFA) Coverage Manuals CD-ROM (through July 1998)

HealthSTAR (Health Services, Technology, Administration, and Research)
(1990 through May 20, 1998)

The search strategies employed a number of free-text keywords, as well as controlled vocabulary terms, including but not limited to:

Diagnostic modalities: barium sulfate; barium swallow; barium; fluoroscopy; cineradiology; videofluoroscopy; FEES (fiberoptic endoscopic evaluation of swallowing); ESE (endoscopic swallowing evaluation); FEED (fiberoptic endoscopic evaluation of dysphagia); FEESST (fiberoptic endoscopic evaluation of swallowing with sensory testing); VEED (videoendoscopic evaluation of dysphagia)

Disorder: deglutition disorders (exploded); deglutition (exploded); dysphagia; swallowing

Epidemiology: epidemiology; research design; epidemiologic study characteristics; epidemiologic methods; epidemiologic studies; evaluation studies; incidence; prevalence; statistics and numbers; aspiration pneumonia; neurodegenerative diseases (exploded); Parkinson disease; silent aspiration; stroke

Etiology: aging; Alzheimer disease; dementia; multiple sclerosis; Parkinson disease; stroke

Miscellaneous: cachexia; wasting; weight loss; quality of life; QOL; life satisfaction; satisfaction

Treatment: speech therapy; speech-language pathology; electrical stimulation; enteral nutrition; intubation, gastrointestinal; nasogastric; nasointestinal; NG; percutaneous endoscopic gastrostomy; PEG tube feeding; rehabilitation, geriatric; rehabilitation; speech and language; rehabilitation, patients; elder care; mobile health units

In addition to the above searches, we conducted searches of the World Wide Web. These searches were conducted using various search engines including (but not limited to) AltaVista, Hotbot, and Yahoo. Searches focused on the areas of dysphagia, aging, neurologic disorders, and pneumonia. Twenty-three Web pages were accessed for this project.

We searched Current Contents - Clinical Medicine on a weekly basis as well as more than 1,600 journals and supplements maintained in our collections. In addition, we conducted a hand search of the Cumulated Index Medicus (1960-1964) for the terms deglutition, deglutition disorders, speech therapy, and speech disorders. We also screened nonjournal publications and conference proceedings from professional organizations, private agencies, and government agencies.

Other mechanisms were used to retrieve additional relevant information, including review of bibliographies/reference lists from peer-reviewed journals and gray literature. (Gray literature includes reports, studies, etc., produced by local government agencies, private organizations, educational facilities, corporations, etc., that do not commonly appear in the published peer-reviewed journal literature.) Published and unpublished information was also solicited from a panel of experts in the field.

The use of these search methodologies, as well as personal communications from several technical experts, resulted in the identification of 4,485 items of information in the form of journal articles, book chapters, manuscripts, monographs, Web pages, personal communications, and other miscellaneous items. Two primary analysts blinded from each other independently reviewed the titles and abstracts of all electronic search results and ordered articles using the following inclusion criteria:

Our broad-based literature searching and broad inclusion criteria ensured retrieval of all relevant information. To further this goal, literature searches were provided to two analysts who independently requested information. Discrepancies in requests were resolved in favor of obtaining the information. Further, literature requested by each analyst was delivered to both analysts who, during initial review of the retrieved literature, reviewed the bibliographies of each article for additional information that might not have been found during the database searches.

In certain instances, more specific inclusion criteria were used. These criteria are described in the appropriate sections of this report.

As a result of our searches, a total of 1,808 articles were retrieved. These included 1,467 clinical trials, 183 review articles, and material from nine World Wide Web sites. In addition, we obtained 32 unpublished articles and received 28 personal communications.

We adopted a flexible scheme for assessing the quality of the literature, which consists of several types of study designs. Among these designs were randomized controlled trials (RCTs), historical prospective case series, case-controlled studies, and case series. In general, we considered data from RCTs to be more reliable than that from studies of other design and considered data from historical prospective case series to be of the second highest level of reliability. We did not, however, rigidly adhere to this scheme because some RCTs had flaws serious enough to render their results unreliable. Similarly, we did not always consider case-controlled studies to provide more reliable information than case series because of certain flaws in the former. These flaws were particularly evident when case controls were used to measure the sensitivity and specificity of diagnostic tests. Such designs artificially set the prevalence and severity of disease, rendering measures of test performance derived from them unreliable.

Because of the scarcity of controlled trials on the effectiveness of dysphagia diagnosis and treatment programs or of treatment per se, a standard meta-analysis that used improvement in patient outcomes as the dependent variable was not possible. Nevertheless, the analytical approach used throughout this evidence report is heavily quantitative. It contains two cost-effectiveness analyses, a meta-analysis (in the form of a summary receiver operator characteristic curve) on the efficacy of the 3-ounce water test, a similar meta-analysis on the efficacy of the BSE, an exploratory meta-analysis (so called because it derives control group data from historical sources) on the efficacy of dysphagia diagnosis and treatment programs, and a meta-analysis that addresses the more technical issue of the low statistical power of vote-counting procedures. In addition to these analyses, our analysis also contains numerous other original calculations. Noteworthy among these is that we calculated all of the 95 percent confidence intervals (CIs) around all of the proportions in the supplemental analyses and Results section of this report. We performed these calculations using a formula that corrects for the spurious results that common formulae for CIs yield when a proportion substantially deviates from 0.5. We also computed all of the Fisher's exact tests shown in this report and used this test as opposed to the ² test or odds ratios because the latter two tests yield suspect results when a zero (or a near zero number) is in one of the cells of the 2 X 2 tables on which these statistics are conducted. We also adjusted for the varying lengths of followup used by different studies (and hence the varying risks of contracting pneumonia) by using a curve fitting procedure and we provide original calculations (or independently verified the published calculations) for all sensitivities, specificities, and positive and negative predictive values shown in the evidence tables of this report. In our suggested clinical trial we provide original statistical power calculations based on our own number needed to treat analysis. Finally, the appendices and supplemental analyses provided with this evidence report contain numerous other original calculations.

This need to perform a substantial number of original calculations is a reflection of the relatively poor reporting and the relatively poor quality of the literature related to this evidence report. Without our original calculations, it would have been extraordinarily difficult to reach meaningful conclusions. We recognize, however, that our attempt to come to conclusions based on studies of relatively poor design is uncommon. However, it must also be recognized that many of today's pressing healthcare questions must be answered in the absence of strong evidence, and that failure to do so imposes serious limitations on the practical applications of evidence-based medicine.

The findings outlined here are applicable only to acute-care stroke patients. Insufficient information was available on patients with other neurologic diseases or conditions, and it is entirely possible that at least some of the findings we present are not applicable to patients with these other diseases and conditions.

In answering this question, we focus on dysphagia diagnosis and treatment programs in general. We address the specific diagnostic tools and the specific treatments that might be used to optimize these programs in Questions 3 and 4, respectively.

Current evidence suggests that implementation of a systematic program of diagnosis and treatment of dysphagia in an acute stroke management plan yields dramatic reductions in pneumonia rates. Because these data are derived from historically controlled studies rather than RCTs, the exact magnitude of this reduction in pneumonia is difficult to determine. Also for this reason, it is equally difficult to determine the contribution of the dysphagia-specific aspects of the management programs to these rate reductions (as opposed to those aspects of the stroke management program not related to diagnosis and treatment of dysphagia). However, because the effects observed in these studies are substantial, it would be imprudent to ignore them. Therefore, these results must be taken as evidence of efficacy of these programs.

Partly for the reasons noted in the preceding paragraph, it seems prudent to include dysphagia-specific management with formal diagnosis and treatment as part of the standard protocol of stroke management in acute-care settings, despite the sparse available data. Also, these programs appear to have a minimal potential to harm patients. Finally, dysphagia diagnosis and treatment programs may be cost-effective. Thus, withholding such programs would deny potential benefits to patients, perhaps at some additional costs.

The risk for developing aspiration pneumonia cannot be accurately predicted from any single clinical sign or symptom. There is a clear-cut need to optimize a brief initial exam that accurately detects patients with possible unsafe swallows and who therefore need more extensive testing. An optimum combination of signs and symptoms for such an initial test has not been determined, and further appropriate research is needed. This research should seek to devise an initial test that has high sensitivity and moderate specificity. This would ensure that the great majority of patients with unsafe swallows are appropriately referred for further testing and that only a minimum number of patients with safe swallows are erroneously referred for more extensive testing.

Neither videofluoroscopy nor fiberoptic endoscopy can serve as a perfect gold standard for detection of aspiration, because each yields false-negative and false-positive results. Without a third, better reference standard, the ability of these two methods to detect aspiration cannot be compared with each other.

Full BSEs can have sensitivities for aspiration near 80 percent, with specificities near 70 percent. Epidemiological evidence indicates that about half of the patients with dysphagia who aspirate do so silently (without a cough). These two points, taken with the very low pneumonia rates observed in dysphagia management programs that used full BSEs, indicate that these exams are capable of detecting most aspiration, even silent aspiration (or that any undetected aspiration does not contribute greatly to the pneumonia rate).

The ability of the full BSE to detect silent aspiration should be optimized in future research. Whether it can be conclusively stated that an optimized full BSE can entirely replace imaging exams such as videofluoroscopy and fiberoptic endoscopy depends partly on the degree to which the BSE is optimized, and partly on the additional benefit that results from the direct internal visual information provided by the imaging exams.

In all studies that attempted to predict pneumonia from the results of a diagnostic test, measurements of the ability of a diagnostic test to predict pneumonia, when expressed in terms of test sensitivity and specificity, were distorted by intervening treatment that prevented some pneumonia from occurring. This distortion cannot be circumvented by withholding treatment, because this would be unethical. Therefore, it does not appear possible to ethically measure either the absolute or relative sensitivities or specificities of dysphagia diagnostic modalities for predicting pneumonia. This also appears to be true for other important patient outcomes such as malnutrition, dehydration, and QOL. This means that the only ethical method of comparing various diagnostic modalities is to conduct controlled trials that measure the combined effects of diagnosis and treatment on the rate of pneumonia and/or other patient outcomes. This limitation on study design provides one reason why the superiority of any given diagnostic method is not conclusively shown by currently available data.

Another reason that current studies do not conclusively show the superiority of any diagnostic test relates to their small size. These studies do not have enough statistical power to allow one to detect the effects of interest, which may be small.

The differences in the ability of various diagnostic tests to predict pneumonia are likely to be small because the two studies using BSEs were so successful (nearly all pneumonia was prevented). It is difficult to obtain a statistically significant improvement upon their results.

Although currently available data do not allow one to determine the degree to which, or even whether, use of videofluoroscopy or other instrumented exams lead to lower pneumonia rates than the full BSE, it is entirely reasonable to expect that their use might lead to lower pneumonia rates. This is because instrumented exams provide more information than the full BSE. Partly for this reason, and even though no data currently demonstrate a difference in effectiveness among diagnostic modalities, one should not conclude that our results prove that the BSE and instrumented exams are equivalent. In terms of patient outcomes, we have found no evidence of a difference between these technologies, not evidence of no difference. Research that appropriately addresses this issue is needed.

Because no data satisfactorily compare the abilities of the full BSE and videofluoroscopy to prevent pneumonia, we constructed two cost-effectiveness models to address this issue. These models, which are based on published protocols and findings, assume that patients will receive a preliminary bedside assessment, and that one result of this assessment is that no more than 39 percent of patients will be referred for further evaluation. Under these conditions, our cost-effectiveness analysis, although based on less than perfect data, suggests that dysphagia diagnosis and treatment programs that employ the BSE would either save money or have very little net cost if they reduced pneumonia rates by amounts similar to those obtained in certain published studies. In addition, our results indicate that the slightly higher costs of videofluoroscopy would be offset if it provided slightly less than an additional 10 percent reduction in pneumonia rates, again assuming that no more than 39 percent of patients are referred for videofluoroscopy or the full BSE.

Some epidemiological evidence suggests that dysphagia patients who aspirate have about a 50 percent greater risk of developing aspiration pneumonia than dysphagia patients who do not aspirate during videofluoroscopy exams. However, the relationship between aspiration and pneumonia is not perfect. Other patient characteristics such as oral hygiene and immune system strength may play equal or even greater roles in causing pneumonia. This loose relationship between aspiration and pneumonia means that aspiration should not be considered a definitive marker for the patient outcome of pneumonia.

Large RCTs measuring patient outcomes such as aspiration pneumonia, malnutrition, dehydration, and QOL are needed to determine the comparative effectiveness of the various dysphagia diagnostic and treatment methods. These trials should enroll patients in reasonably homogeneous disease groups or stratify patients into appropriate subsets. We have included detailed suggestions for such studies along with some estimates of the number of patients needed.

Most study designs used in the evaluation of noninvasive therapy have made it impossible to assess the effectiveness of individual treatments.

The results of a single RCT supported the use of a soft mechanical diet over a pureed diet for preventing aspiration pneumonia in stroke patients with dysphagia who had a history of aspiration pneumonia.

A single RCT reported inconclusive results about the effect of treatment intensity level on patient outcomes. The statistical power of this trial may have been too low to detect the appropriate differences.

Research in the areas of diagnosis and treatment of dysphagia in neurologic patients has thus far largely focused on stroke patients, who comprise the largest proportion of patients with dysphagia, and has mostly been conducted as case reports and small case series. Only a few randomized trials have been attempted, and a few additional studies included historical controls. Future research needs to be conducted on all aspects of dysphagia. Our suggestions for study design and methodology are outlined below.

Results from patients whose dysphagia is caused by different diseases, disorders, or conditions should not be combined. When they are combined, it is probable that the results of a study will be influenced as much, if not more, by patient characteristics than by treatment.

Patient outcomes should be analyzed by stage of disease. For example, combining results obtained from patients soon after a stroke and results obtained from patients weeks or months after a stroke is inappropriate. Here, too, patient characteristics can have an undue influence on the overall results of a study.

Case series provide extremely limited information. RCTs are preferable, but where they are not ethical, controlled studies of other design should be employed. Randomization of patients to receive diagnosis by different methods is ethical because no single diagnostic has yet been proven superior to any other. This is not necessarily the case in the treatment of dysphagia, where randomizing patients to an untreated group may be unethical. If a control group is deemed unethical, the comparison group should be a similar patient population receiving a different treatment or different level of treatment.

Studies should focus on assessing overall dysphagia management programs because of the difficulty of separating diagnosis and treatment in this field.

Researchers should specify the kind of pneumonia they are studying. Results from patients with aspiration pneumonia should be reported separately from results from patients with pneumonia resulting from other causes (understanding, however, that the distinction between these two diagnoses is generally a hypothesis, rather than certainty, because of difficulty in ascertaining the etiology of pneumonia).

More study of whether dysphagia causes malnutrition and/or dehydration is required. If such a causal relationship is confirmed, investigators should begin to report these measures as outcomes.

Researchers need to report the specific causes of patient mortality, thus making it clear whether a patient died from complications resulting from dysphagia, or from the primary disease.

Additional information on the QOL of patients with dysphagia, and on the degree to which treatment of dysphagia improves QOL, is needed. QOL should be measured using standard methods.

Studies on feeding tube efficacy should separately report results obtained in patients with dysphagia and should not combine such results with feeding tubes placed for other reasons.

Patients should be followed for longer times than those used in available studies. Followup times should be standardized within any given study so that all patients are followed for approximately the same length of time.

Investigators comparing two diagnostic methodologies should ensure that patients in different groups do not receive different treatment, or comparisons between the two are no longer feasible.

Because of the shortcomings in available research, we suggest a multiarm, randomized trial to evaluate the efficacy of different dysphagia management programs. The primary outcome of this trial should be aspiration pneumonia rates, but other outcomes, such as those related to malnutrition and dehydration, should also be measured. The trial can consist of two to four groups, but for the purposes of illustration, we will describe it here as if it consisted of four. In this trial, the control group would consist of patients randomized to receive a full BSE alone; the three experimental groups would consist of patients randomized to receive the full BSE plus one of three possible instrumented examinations. Readers of the instrumented examinations would be blinded to the results of the BSE. The results of the BSE would be used to determine whether combinations of signs and symptoms predicted aspiration pneumonia and other outcomes. Treatment choices in the group that received only the BSE and in the groups that received the instrumented exams would be appropriately based on each of these exams. The results of this trial could be extended using decision analysis and cost-effectiveness analysis. Only if data from such a trial are available will it be possible to conclude definitively whether one exam is superior to another in reducing the incidence of aspiration pneumonia and/or other adverse outcomes.