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S V Williams

Publications and source records attributed to S V Williams.

71 records · Page 4Linked to original sources
PubMed1981

Cost containment and changing physicians' practice behavior. Can the fox learn to guard the chicken coop?

The important role of physicians in the generation of medical care costs is evident, but methods of inducing physicians to participate in cost-containment efforts are not well developed. Efforts to change physicians' use of medical services have included education, peer review and feedback, administrative changes, participation, penalties, and rewards. Although educational programs have had mixed success, those using individualized instruction have been most effective. Several feedback and peer-review programs have demonstrated reductions in costs, as have administrative interventions. While penalties and direct rewards may be effective, alterations in the current reimbursement system could offer financial incentives to physicians who practice in a cost-effective manner.

Cost Control↗
PubMed1981

Diagnostic services utilization review at a university medical center.

The rational provision of diagnostic services is important in maintaining health care quality and controlling costs. Establishing a successful diagnostic services utilization review committee requires substantial commitment from the hospital and the medical staff.

Diagnostic Services↗
PubMed1977

Computer-based audit to detect and correct overutilization of laboratory tests.

We developed a computer-bases system to detect inappropriate use of the clinical laboratory and tested a program of physician education to reduce overutilization. We modified the hospital laboratory's computerized reporting system to identify medical patients with three or more determinations of lactic dehydrogenase (LDH) or calcium during the preceding seven days. We audited the charts of these patients, using explicit criteria, to determine whether multiple studies were justified. During the control period 51 per cent of the charts audited for multiple determinations of LDH revealed overutilization. During the study period, when physicians were notified if overutilization was found, 65 per cent of the charts showed overutilization. This difference was not significant. A simultaneous, undisclosed audit of calcium determinations also showed no change between the two periods. Therefore, this method is effective in detecting and measuring overutilization of the laboratory. It is a method which is easily adaptable to a hospital's computerized laboratory reporting system, and it can be applied without a computer. However, our program of notification and education of physicians is not effective in reducing overutilization. More effective methods of modifying physicians' use of laboratory tests need to be developed.

Calcium↗
PubMed1975

Dental infection with hepatitis B.

We performed a prospective study to assess the risk of patients acquiring infection following routine professional contact with two dentists incubating type B viral hepatitis. Serum samples from patients exposed during the six weeks before onset of hepatitis in the dentists were tested for hepatitis B surface antigen and for antibody to the antigen shortly after illness developed and again six months later. Household members of exposed patients served as a control group. None of the exposed patients or controls became ill with hepititis, and none developed antigen. Three of the 237 exposed patients developed antibody, as did four of the 245 controls. The difference between exposed patients and controls was not significant. These results do not support the hypothesis that these two dentists transmitted infection to their patients.

Carrier State↗
PubMedDate not supplied

A controlled trial to decrease the unnecessary use of diagnostic tests.

A controlled trial evaluated a program to decrease the unnecessary use of inpatient testing by medical residents in a university medical center. The program included education, concurrent feedback, and resident participation in program planning. Using specific criteria for 7,891 chart audits of patients who had repeat tests within seven days, the authors measured change in testing among 44 residents in the first year and 43 in the second year. There were no significant differences related to the program. They conclude that substantial overuse of diagnostic tests did occur, that it varied from hospital to hospital, and that the program could not overcome powerful counteracting influences. Future studies, using control groups and chart audits, should evaluate interventions other than education.

Clinical Laboratory Techniques↗
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

The single-cutoff trap: implications for Bayesian analysis of stress electrocardiograms.

Quantitative analysis of exercise electrocardiograms has been emphasized by many investigators. Specific problems have been found when a single cutoff is used to define a positive or a negative test: a single cutoff does not distinguish stress electrocardiography results that are slightly positive from those that are markedly positive. This may lead clinicians to underweigh strong evidence for or against coronary artery disease. This study evaluated clinicians' quantitative analysis of stress electrocardiograms. Two hundred and thirty-five physicians interpreted the results of mildly positive (1.2 mm ST-segment depression) and strongly positive (2.2 mm ST-segment depression) stress electrocardiograms. Their posttest probability estimates were too high for a mildly positive test (0.62 +/- 0.02 versus actual of 0.38; p less than 0.001) and too low for a strongly positive test (0.77 +/- 0.01 versus actual of 0.98; p less than 0.001). Physicians should understand decision aids and should use multiple rather than single cutoffs to interpret the results of stress electrocardiography.

Bayes Theorem↗
PubMedDate not supplied

Assessing physicians' estimates of the probability of coronary artery disease: the influence of patient characteristics.

The authors assessed physicians' probability estimates of coronary artery disease (CAD) in 250 patients undergoing a screening exercise stress test. True likelihood of disease (prevalence) was derived from the literature. Discrimination and calibration were assessed by comparing physicians' probability estimates and prevalence using pairwise comparisons, rank correlation, and linear regression. There were differences in the discriminative abilities of the physicians based on patient characteristics. For example, the physicians had better discriminative ability for patients with typical cardiac chest pain compared with atypical chest pain. The physicians were able to predict the prevalence of CAD in broad groups of patients. However, they overestimated probabilities for patients with low prevalence of disease and underestimated probabilities for patients with high prevalence of disease. The authors conclude that physicians make consistent errors in the use of probability estimates. The quality of these estimates depends on patient characteristics such as type of chest pain and true likelihood of disease.

Angiography↗
PubMedDate not supplied

Blood lead in children and its determinants in Nagpur, India.

In a community-based cross-sectional study of 297 children aged 6 months to 6 years in an Indian city, the authors assessed the prevalence of elevated (> or = 10 microg/dL) blood lead (PbB) levels, their risk factors, and the lead contents in potential environmental sources. Mean PbB was 18.4 microg/dL +/- 16.5. The prevalence of elevated PbB was 67%. Anticipated risk factors for elevated PbB were living in houses painted with lead-based paint, odds ratio (OR) 6.42 (1.75, 23.6; p = 0.005), recent exposures to lead-based paint, OR 2.61 (1.07, 6.66; p = 0.03), and the use of the eye cosmetic ma," OR 2.63 (1.24, 5.56; p = 0.01). Unanticipated results were effect of upper caste as a risk factor, OR (adjusted) 1.85 (95% CI = 0.96, 3.57; p = 0.06), and the lack of effect of traffic, parental occupational exposure, or nutritional status. Analysis of various environmental sources such as paint, pencils, crayons, and clay revealed high lead levels. These results demonstrate the existence of a major environmental health problem in Indian children, with risk factors that differ from those in other countries.

Child↗