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Biomedical subjects

R D Cebul

Publications and source records attributed to R D Cebul.

52 records · Page 3Linked to original sources
PubMed1985

The accuracy of experienced physicians' probability estimates for patients with sore throats. Implications for decision making.

Ten physicians recorded their treatment decisions and estimated probabilities of streptococcal infection for patients with sore throats. Of 308 throat cultures, 15 (4.9%) were positive for group A streptococci. The physicians overestimated the probability of a positive culture for 81% of their patients and their estimates and treatment decisions were strongly associated. Of 104 patients treated before culture results were available, only eight had positive cultures. Probability overestimation may have been due to neglect of the low culture-positive rate, assignment of undue importance to weakly predictive or highly intercorrelated clinical features, and a value-induced bias, occurring when features important for treatment are erroneously linked to the likelihood of disease. Cognitive limitations in information processing may limit the effectiveness of pharyngitis management protocols that require subjective estimates of disease probability.

Adolescent↗
PubMed1984

'A Look at the Chief Complaints' revisited. Current obstacles and opportunities for decision analysis.

In 1979, Dr. William Schwartz wrote a "Sounding Board" article in the New England Journal of Medicine entitled: "Decision Analysis. A Look at the Chief Complaints". In it, he listed the major concerns of practicing physicians, academicians, and students about decision analysis. As an educator and an advocate of the technique, he then replied to each of these concerns and objections. Dr. Schwartz's article is an excellent and thoughtful discussion and one that we routinely recommend to our students to prepare them for real-world reactions to the zeal with which they often leave our classrooms. Now, more than four years later, I would like briefly to review the "chief complaints" outlined by Dr. Schwartz and to update them to 1984. My purpose is to consider the cognitive and practical obstacles to the dissemination of decision analysis, and to discuss alternative approaches to surmounting these obstacles. To do this, I have engaged four "consultants" from different fields.

Attitude of Health Personnel↗
PubMed1984

A course in clinical decision making adaptable to diverse audiences.

Faculty at the University of Pennsylvania have developed a prototype course in clinical decision making that can be adapted to the diverse backgrounds of a variety of medical audiences. The course was offered in its entirety to third and fourth-year medical students and in abbreviated form to two postgraduate audiences (community and university-based physicians) during 1982. Methods were developed for content, process, and outcome evaluation for the courses; the latter consisted of pretest and posttest comparisons of performance on a written examination. Ninety-four individuals attended one or more sessions of the three courses. All courses were very favorably received, although the postgraduate audiences perceived less clinical relevance than educational relevance in the material (p less than 0.05). The medical students performed better on the pretest than either group of physicians, with the student-university physician difference reaching statistical significance (p less than 0.01). Nevertheless, all groups performed better on the posttest than on the pretest (p less than 0.001) and the degree of improvement was no different among the groups (p greater than 0.29). We conclude that our course's concepts and skills can be effectively adapted to and assimilated by physicians at all levels of training and experience.

Curriculum↗
PubMed1982

Noninvasive neurovascular tests for carotid artery disease.

Indirect noninvasive neurovascular tests provide information on hemodynamic changes cephalad to the carotid bifurcation, whereas direct tests measure anatomic or physiologic changes at the bifurcation itself. Batteries of tests are often done and should combine both indirect and direct methods. Results with two ultrasonic techniques and digital subtraction intravenous angiography suggest a larger role for these methods. Carotid arteriography is the definitive procedure for evaluating the carotid artery, although it should only be done when carotid endarterectomy is contemplated. The relative risks and benefits of other diagnostic and therapeutic management strategies should guide the decision to do noninvasive neurovascular tests, or to proceed directly to arteriography.

Carotid Artery Diseases↗
PubMed1980

Antitumor effects of doxorubicin against a virally-induced rat osteosarcoma with minimal immunosuppression.

Intratibial inoculation of a Moloney strain of Murine Sarcoma Virus (MSV-M) in neonatal Wistar-Lewis rats produced osteosarcoma in 96% of animals and resulted in a median survival of 20 days. Intraperitoneal (i.p.) administration of doxorubicin (adriamycin) (1-2 mg/kg/d, on day 10-12) resulted in reduced tumor growth and prolonged median survival to 95+ and 64 days, respectively. Higher dose doxorubicin (3-4 mg/kg/d, on day 10-12) caused early lethal toxicity. Autopsy data revealed a characteristic sarcomatous tumor producing osteoid. Gross pulmonary nodules appeared in 30% of both treated and untreated animals. Microscopic evaluation of lung tissue revealed anaplastic tumors without osteoid in as many as 90% of rats. Hepatosplenomegaly was usually present but microscopic sections of the spleen did not reveal tumor. Long bone metastases were increased in frequency in those animals receiving doxorubicin. Cell mediated immunity (CMI) to osteosarcoma cells by peripheral blood lymphocytes of tumor-bearing animals was detectable between days 21-48. This was bimodal with an early peak at day 21 (CMI = 56%) and a late peak at day 39 (CMI = 48%). CMI in rats given 1 mg/kg/d x 3d of doxorubicin was similar, with peak cytotoxicity (CMI = 61%) on day 26. Two mg/kg/d x 3d of doxorubicin did not significantly suppress either the early response (CMI = 50% on day 22) or the second peak (CMI = 38% and 50% on day 40 and 46, respectively). Thus, doxorubicin was effective in decreasing the growth of an MSV-M induced osteosarcoma and prolonging survival in the rat while usually failing to suppress CMI against rat osteosarcoma cells.

Animals↗
PubMedDate not supplied

Indications, outcomes, and provider volumes for carotid endarterectomy.

CONTEXT: While trials have demonstrated that carotid endarterectomy is superior to best medical therapy, most recently among asymptomatic patients, uses and outcomes of the procedure in more representative settings have not been established. OBJECTIVES: To profile the use and outcomes of carotid endarterectomy in a representative sample of Ohio's Medicare beneficiaries and to examine the relationships between provider-specific procedural volumes and patient outcomes. DESIGN: Retrospective cohort using Medicare Provider Analysis and Review files supplemented by detailed reviews of medical records on a random sample of patients. SETTING: Ohio hospitals performing carotid endarterectomy. PATIENTS: A random sample of 678 charts of the 4120 non-health maintenance organization Medicare beneficiaries who underwent carotid endarterectomy between July 1, 1993, and June 30, 1994. MAIN OUTCOME MEASURES: Nonfatal stroke or death within 30 days of surgery. RESULTS: The reviewed patients were similar to all eligible patients in sociodemographic characteristics and 30-day mortality rates. Among the 678 patients, indications for surgery were asymptomatic carotid stenosis in 167 (24.6%), transient ischemic attack in 294 (43.4%), completed stroke in 62 (9.1%), and nonspecific symptoms in 155 (22.9%). Thirty-two patients (4.7%) died or suffered nonfatal strokes by 30 days postoperatively. In univariate analyses, rates varied by hospital volume (P=.004) but not surgeons' volume (P=.47), although power to detect this difference was limited. Patients at higher- and lower-volume hospitals had similar indications and distributions of comorbidities. In analyses controlling for indications, comorbid conditions, and surgeon's volume, being operated on in a higher-volume hospital conferred a 71% reduction in risk for 30-day stroke or death (odds ratio, 0.29; 95% confidence interval, 0.12-0.69; P=.006). CONCLUSIONS: Almost half (47.5%) of the carotid endarterectomies among Ohio's Medicare population are performed on persons who are asymptomatic or who have nonspecific symptoms. These results highlight the importance of identifying patients and providers having the most favorable outcome profiles. The higher rate of adverse outcomes observed in lower-volume hospitals deserves further investigation, as it does not appear to be due to differences in patient selection.

Aged↗
PubMedDate not supplied

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↗
PubMedDate not supplied

Clinical guidelines for using two dichotomous tests.

Building on the threshold model developed by Pauker and Kassirer for a single test, the authors describe a decision analytic model for two tests with dichotomous outcomes. The model includes ten decision strategies that differ depending on which tests are performed, whether the tests are performed together or in sequence, and the definition of a positivity criterion used to make the treatment decision when the test results disagree. Formulas derived from the model are used to compute the preferred option as a function of disease probability and to calculate test and test-treatment thresholds. General guidelines developed from the model can be used without calculation to identify relative preferences for alternative options and to predict threshold effects.

Diagnosis↗
PubMedDate not supplied

Multiple test analyzer (MTA): a microcomputer program for determining preferred strategies with two diagnostic tests.

There are ten distinct management strategies in clinical situations that involve two diagnostic tests with dichotomous outcomes. The authors describe a microcomputer program, based on a previously described model, that can be used to identify test and test-treatment thresholds and to compute preferred strategies. The program provides tables and graphs of the results, which can be viewed or printed, and there is an optimization routine that facilitates comprehensive analysis. It can be used by decision-analytic researchers and policy analysts, medical educators who teach decision analysis, and clinicians who use decision analysis in their practices.

Computers↗
PubMedDate not supplied

The importance of considering single testing when two tests are available.

When considering two dichotomous tests in combination for reaching a treatment decision, the choice between single and multiple testing depends, in part, on the pretest probability of disease. The authors show that two tests are never preferred to a single test for all disease probabilities, regardless of whether the two tests are performed in parallel or in series.

Decision Making↗
PubMedDate not supplied

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↗
PubMedDate not supplied

Practice variation in the management of pharyngitis: the importance of variability in patients' clinical characteristics and in physicians' responses to them.

The objective of this study was to assess whether geographic differences in antibiotic-prescribing rates for patients with pharyngitis could be explained by intersite differences in patients' clinical characteristics and in how physicians responded to these clinical cues when making decisions. As part of the initial phase of a prospective controlled trial to improve physicians' diagnostic ability, the authors enrolled cohorts of consecutive patients seen at staff-model--HMO student health services in Pennsylvania and Nebraska. Physicians' decisions whether to prescribe antibiotics for 310 consecutive patients presenting with pharyngitis to the former and 214 such patients presenting to the latter at the time of the initial visit were examined. There was a large discrepancy between the antibiotic-prescribing rates at the student health services in Pennsylvania, 106/310, 32.4%, and Nebraska, 156/214, 72.9%. The clinical variables significantly independently associated with treatment at both sites in a logistic regression model were fever, adjusted odds ratio = 2.1 (95% CI = 1.1, 3.8); exudates, 5.4 (2.8, 10); palatine petechiae, 6.5 (1.5, 28); rhinorrhea, 0.46, (0.25, 0.85); and high risk of complications, 3.8 (1.04, 14). There was a significant interaction between site and anterior cervical adenopathy, 5.5 (1.6, 19); and a borderline interaction between site and rhinorrhea, 2.4 (0.89, 6.7). Site was not a significant independent predictor of treatment, 1.8 (0.45, 6.6.). Practice variation was related to geographic differences in patients' clinical characteristics and in how physicians responded to these factors when prescribing antibiotics. How physicians weight patients' clinical characteristics when making decisions may be an important element of their "practice styles."

Anti-Bacterial Agents↗
PubMedDate not supplied

You can lead a horse to water--improving physicians' knowledge of probabilities may not affect their decisions.

OBJECTIVES: To determine whether improving physicians' judgments of the probability of streptococcal pharyngitis for patients with sore throats would affect their use of antibiotics and affect the variation in such use. DESIGN: Post-hoc retrospective analysis of data previously collected as part of a controlled trial. SETTINGS: University student health services in Pennsylvania and Nebraska. PATIENTS: Sequential patients with pharyngitis seen before and after the time clinicians received either an experimental educational intervention designed to improve probabilistic diagnostic judgments (at the Pennsylvania site) or a control intervention, a standard lecture (at the Nebraska site). The clinician-subjects were the primary case physicians practicing at either site. MEASUREMENTS: Clinical variables prospectively recorded by the clinicians, probability assessments, and treatment decisions. RESULTS: At the experimental site, despite marked decreases in clinicians' overestimations of disease probability after the intervention, the proportion of patients prescribed antibiotics showed a trend toward increasing: 100/290 (34.5%) pre-intervention, 90/225 (40%) post-intervention. The intervention did not decrease practice variation between individual doctors. Univariable and multivariable analyses showed no major change in the relationships between clinical variables and treatment decisions after the intervention. At the control site there was no major change in probability judgments or treatment decisions after the intervention. CONCLUSIONS: Teaching physicians to make better judgments of disease probability may not alter their treatment decisions.

Anti-Bacterial Agents↗