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Biomedical subjects

R D Cebul

Publications and source records attributed to R D Cebul.

16 recordsLinked to original sources

Controlled trial using computerized feedback to improve physicians' diagnostic judgments.

The goal of this study was to test an innovative method to improve physicians' diagnostic judgments by integrating the use of a computer program (employing cognitive feedback to teach a clinical rule that predicts the probability of streptococcal pharyngitis), a traditional lecture, and periodic disease-prevalence reports. In a controlled trial using pre- and postintervention measures involving 885 patients, the authors compared the effects of the integrated method on the diagnostic judgments of seven experienced physicians at a university health service (from 1982 to 1985) with the effects of the lecture alone on the judgments of seven experienced physicians at a different university health service (1986 to 1987). The integrated method significantly improved the quality of the physicians' judgments as measured by calibration curves and Brier scores, and increased the level of agreement between the physicians' judgments and those made by the clinical prediction rule. The lecture alone produced less improvement in the quality of the physicians' judgments, and decreased the level of agreement with the rule. The authors conclude that this method, based on cognitive psychology, is a promising educational tool.

Computer-Assisted Instruction

Efforts to improve compliance with the National Cholesterol Education Program guidelines. Results of a randomized controlled trial.

STUDY OBJECTIVE: We compared three approaches for improving compliance with the practice guidelines of the National Cholesterol Education Program (NCEP). DESIGN: A randomized controlled trial. SETTING: Academic group practices of a major urban teaching hospital. PARTICIPANTS: Study physicians were three equivalent groups of PG-2 and PG-3 residents (N = 33) seeing patients in equivalent outpatient clinics. Continuity patients of these residents were included (N = 240) if they were younger than 66 years, saw their primary physician during the intervention period, were not pregnant, and had no serious life-shortening noncardiac illnesses. INTERVENTIONS: Three interventions were implemented over a 5-week period. Control group physicians (group 1) were offered only a standard lecture provided through the Physician Cholesterol Education Program (PCEP). Group 2 physicians were offered the PCEP lecture and also received generic chart reminders of the NCEP guidelines on each eligible patient's chart. Group 3 physicians were offered the PCEP lecture and also received timely patient-specific feedback, including acknowledgement of recent lipid values and management, and explicit recommendations for further action. Knowledge of lipid disorders was tested before and after the PCEP lecture, and physicians' attitudes were surveyed following the intervention period. MEASUREMENTS AND MAIN RESULTS: The three groups were similar in baseline (preintervention) compliance with NCEP recommendations (average, 39%) and physicians' knowledge. Patients were similar across groups in number of coronary artery disease risk factors and cholesterol values. Significant within-group improvements in compliance were noted for groups 2 and 3 (7.6% and 10.6%, respectively), but not for group 1 (4.5%). Importantly, there were no differences observed in improvements across groups. In exploratory analyses, however, there was a significant correlation between improved compliance and the number of patients seen by each provider in group 3 that was not observed in groups 1 or 2. Notably, changes in compliance were unrelated to PCEP lecture attendance (8.6% vs 8.1% for attenders vs nonattenders, respectively), level of postgraduate training, baseline or later tests of knowledge, or patient factors. The postintervention survey revealed marked overestimation by physicians of their personal compliance with NCEP guidelines, although there was strong support for clinic efforts that would screen patients for lipid disorders independent of physician initiative. CONCLUSIONS: This study raises questions about the effectiveness of education alone for improving compliance with NCEP guidelines. The effectiveness and efficiency of timely, individualized feedback should be explored in studies over a longer period. Innovative alternative approaches are suggested by the responses to our survey and other research in preventive practices.

Ambulatory Care

Randomized, controlled trials using the Metro Firm System.

The Firm System at MetroHealth Medical Center was begun almost two decades ago to foster improved continuity of patient care and teaching of medical students and residents in Internal Medicine. For the past 8 years, these parallel teams of providers and patients also have been used to conduct clinical, educational, and health care delivery research. Randomized, controlled trials are made possible by ongoing random assignment of patients and providers to the three teams, or small group practices. Each group practice has equivalent inpatient and outpatient areas supported by nonrotating nursing, paramedical, and clerical staff. The system's current relationships were established after a controlled trial established both decreased costs and increased effectiveness of the "group practice model" as compared to more traditional approaches to patient care by residents in an academic medical center. Other trials, both on the inpatient and outpatient settings, have been used to guide ongoing institutional change. The unique advantages of the randomized controlled trial are high-lighted by contrasting the results of within-group changes during an intervention with results that incorporate control group changes. A variety of methodologic and logistical issues must be addressed when conducting controlled trials that use ongoing randomization within a single institution. These include determination that the groups are equivalent for all important parameters preintervention, choosing an analytic approach that accounts for potential differences among providers and patients, and, in trials designed to affect behavior, assurance that a "steady state" exists prior to initiating another trial designed to affect similar behavior. Consideration also must be given to the possibilities of cross-team contamination, the Hawthorne effect, the "dominant attending effect," and ethical issues related to informed consent. Clinical trials in a single institution may be performed for common problems and those with well defined stages of severity. Since the costs of maintaining the ongoing randomization are relatively small, the incremental costs of conducting randomized controlled trials are low by comparison to traditional approaches. The establishment of analogous systems at other institutions will permit multisite trials for less common clinical problems, enhance the generalizability of findings, and permit new types of health services research, including the rigorous evaluation of practice guidelines.

Health Services Research

Carotid endarterectomy.

STUDY OBJECTIVE: To evaluate the usefulness of doing carotid endarterectomy in patients with symptomatic or asymptomatic carotid artery disease. DESIGN: Synthesis and summarization of data on the untreated course of cerebrovascular disease, and review of selected evidence and expert opinion on the risks and benefits of endarterectomy and medical therapy. MAIN RESULTS: There is a large body of data related to the untreated course of cerebrovascular disease, the efficacy of aspirin in patients with transient ischemic attacks, and the comparative responsiveness to surgery of symptomatic patients with different presentations. Randomized trials in progress will increase the knowledge about the effects of aspirin in asymptomatic patients, the comparative efficacy of aspirin and endarterectomy in asymptomatic and symptomatic patients, and the factors that influence surgical risk. Clinicians and investigators wish to define a more limited and precise set of indications for carotid endarterectomy. In setting standards, attention has properly focussed on "maximum acceptable complication rates," native stroke risk, and surgical efficacy for patients with different clinical presentations. Illustrative, acceptable surgical mortality rates are less than 1%, and stroke-related morbidity is less than 3% for patients who have had a transient ischemic attack; surgical mortality and stroke-related morbidity are less than 2% for patients with asymptomatic carotid stenosis. Medical comorbidity and angiographic findings are important factors affecting specific recommendations. CONCLUSIONS: Data from ongoing clinical trials will provide a more scientific foundation for recommendations about when to do carotid endarterectomy. Current evidence suggests that fewer endarterectomies should be done, and those on the basis of a more precise set of indications. Clinicians should consider the clinical presentation, the patient's comorbidity and native stroke risk, angiographic findings, and the experience of the surgical team.

Anticoagulants

Guiding individual decisions: a randomized, controlled trial of decision analysis.

In early 1983, all 1,280 faculty and resident physicians at one hospital who were eligible to be vaccinated against hepatitis B were divided randomly into three groups: Group 1 physicians received general information about the risks and benefits of alternative vaccine decisions; Group 2 physicians were additionally invited to provide personal information for an individualized decision analysis (12.6 percent responded); and Group 3 physicians, who served as controls, were not contacted. In one year's follow-up, 20 percent of physicians were screened for hepatitis B antibody or vaccinated. More Group 2 physicians whose decision analyses recommended screening or vaccination took these actions (39 percent) than any other group. Group assignment remained significantly associated with vaccine decisions after analyzing results by the "intention to treat" principle, and after adjusting for training status, exposure to blood and blood products, and pre-study intentions about the vaccine. Despite the low overall vaccine acceptance rate, it is concluded that individualized decision analysis can influence the clinical decisions taken by knowledgeable and interested patients.

Clinical Trials as Topic

The comparative cost-effectiveness of statistical decision rules and experienced physicians in pharyngitis management.

We examined whether probability-based decisions for streptococcal pharyngitis, using probabilities derived from predictive models along with Tompkins' decision rules, could be more cost-effective than the actual decisions of ten physicians. We retrospectively calculated the probability of a positive throat culture ("disease") for each of 310 patients using four different models based on discriminant analysis (1), a branching algorithm (2), and logistic regression (3 and 4). "Projected decisions" were based on these probabilities and Tompkins' rules. We calculated direct medical and indirect costs per correct action taken (diseased patient-treated or nondiseased patient-not-treated). Two models' projected decisions were more cost-effective than the physicians'. Model 1 primarily would have reduced treatment costs (leaving no diseased patient untreated); model 4 primarily would have reduced throat culture costs (with 15% projected undertreatment). While using statistical decision rules may be cost-effective in this setting, their adoption should be consistent with physician and patient priorities.

Algorithms

The importance of disease prevalence in transporting clinical prediction rules. The case of streptococcal pharyngitis.

Because clinical prediction rules often are applied in new settings to calculate the probability of a disease, we evaluated the accuracy of three rules for predicting streptococcal pharyngitis in 310 patients. Use of the rules led to overestimations of disease probability in 47%, 82%, and 93% of the patients. When we used receiver-operating characteristic curve analysis, no rule lost power to discriminate streptococcal from nonstreptococcal causes of pharyngitis. The overestimations in disease probability likely were caused by differences in disease prevalence between our setting (5%) and the settings in which they were developed (15% to 17%). All rules led to accurate predictions when they were adjusted for the disease prevalence found in our setting using a likelihood ratio formulation of Bayes' theorem. The value of prediction rules, like that of other diagnostic tests, is affected by differences in disease prevalence in different settings. Failure to recognize and adjust for these differences may cause poor decision making or the premature dismissal of valid rules.

Humans

Pursuit of abnormal coagulation screening tests generates modest hidden preoperative costs.

To measure the follow-up costs of preoperative coagulation screening tests, the authors studied 829 consecutive patients undergoing inpatient orthopedic surgery. The results of the initial prothrombin and activated partial thromboplastin time tests were divided into three groups: normal; abnormal above the hospital laboratory's upper limit of normal but below an "action limit"; and abnormal above an action limit. Patients with abnormal preoperative coagulation screening test results were matched on the basis of operative procedure and age with patients who had normal results. The matched groups of patients were compared according to preoperative length of stay and the cost of subsequent related preoperative testing. The average cost of follow-up preoperative testing for patients with abnormal screening test results was $5.05, compared with $0.58 for patients with normal screening results. The difference in average preoperative lengths of stay was not statistically significant. The attributable cost of evaluating an abnormal result added 3% to the cost of the initial coagulation screening program. This represents an average preoperative cost of $0.36 per patient in addition to the cost of the screening tests themselves.

Blood Coagulation Disorders

Evaluating physicians' probabilistic judgments.

Physicians increasingly are challenged to make probabilistic judgments quantitatively. Their ability to make such judgments may be directly linked to the quality of care they provide. Many methods are available to evaluate these judgments. Graphic means of assessment include the calibration curve, covariance graph, and receiver operating characteristic (ROC) curve. Statistical tools can measure the significance of departures from ideal calibration, and measure the area under ROC curve. Modeling the calibration curve using linear or logistic regression provides another method to assess probabilistic judgments, although these may be limited by failure of the data to meet the model's assumptions. Scoring rules provide indices of overall judgmental performance, although their reliability is difficult to gauge for small sample sizes. Decompositions of scoring rules separate judgmental performance into functional components. The authors provide preliminary guidelines for choosing methods for specific research in this area.

Decision Theory