Articles on diagnostic tests: a new series and an invitation to authors.
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Diagnostic Techniques and Procedures↗
Biomedical subjects
Alan M Garber
Publications and source records attributed to Alan M Garber.
Utilization and outcomes of the implantable cardioverter defibrillator, 1987 to 1995.
BACKGROUND: The patterns of adoption of the implantable cardioverter defibrillator (ICD) and the outcomes of its use have not been well documented in general, unselected populations. The purpose of this study was to document the impact of the ICD in widespread clinical practice. METHODS: We identified ICD recipients by use of the hospital discharge databases of Medicare beneficiaries for 1987 through 1995 and of California residents for 1991 through 1995. The index admission for each patient was linked to previous and subsequent admissions and to mortality files to create a longitudinal patient profile. RESULTS: The rate of ICD implantations increased >10-fold between 1987 and 1995, as both the number of hospitals performing the procedure and the volume of ICD implantations per hospital rose. Mortality rates within 30 days of ICD implantation decreased from 6.0% to 1.9%, and mortality rates within 1 year fell from 19.3% to 11.4%. Surgical interventions to revise or replace the ICD within the first year remained about 5%, however, and cumulative expenditures at 1 year ($46,000-$51,000) changed very little. ICD implantation rates varied >3-fold among different regions of the United States. CONCLUSIONS: ICD use has expanded markedly during the study period, with improved mortality rates, but medical expenditures and rates of surgical revision remain high for ICD recipients.
Age Factors↗
Trends in hospital treatment of ventricular arrhythmias among Medicare beneficiaries, 1985 to 1995.
BACKGROUND: Treatment options for patients with ventricular arrhythmias have undergone major changes in the last 2 decades. Trends in use of invasive procedures, clinical outcomes, and expenditures have not been well documented. METHODS: We used administrative databases of Medicare beneficiaries from 1985 to 1995 to identify patients hospitalized with ventricular arrhythmias. We created a longitudinal patient profile by linking the index admission with all earlier and subsequent admissions and with death records. RESULTS: Approximately 85,000 patients aged > or =65 years went to hospitals in the United States with ventricular arrhythmias each year, and about 20,000 lived to admission. From 1987 to 1995, the use of electrophysiology studies and implantable cardioverter defibrillators in patients who were hospitalized grew substantially, from 3% to 22% and from 1% to 13%, respectively. Hospital expenditures rose 8% per year, primarily because of the increased use of invasive procedures. Survival improved, particularly in the medium term, with 1-year survival rates increasing between 1987 and 1994 from 52.9% to 58.3%, or half a percentage point each year. CONCLUSION: Survival of patients who sustain a ventricular arrhythmia is poor, but improving. For patients who are admitted, more intensive treatment has been accompanied by increased hospital expenditures.
Aged↗
Perinatal screening for group B streptococci: cost-benefit analysis of rapid polymerase chain reaction.
OBJECTIVE: To evaluate the costs and benefits of a group B streptococci screening strategy using a new, rapid polymerase chain reaction test in a hypothetical cohort of expectant mothers in the United States. METHODS DESIGN: Cost-benefit analysis using the human capital method. We developed a decision model to analyze the costs and benefits of a hypothetical group B streptococci screening strategy using a new, rapid polymerase chain reaction test as compared with the currently recommended group B streptococci screening guidelines-prenatal culture performed at 35 to 37 weeks or risk-factor-based strategy with subsequent intrapartum treatment of the expectant mothers with antibiotics to prevent early-onset group B streptococcal infections in their infants. PARTICIPANTS: A hypothetical cohort of pregnant women and their newborns. INTERVENTIONS: Screening strategies for group B streptococci using the new polymerase chain reaction technique, the 35- to 37-week culture, or maternal risk factors. OUTCOME MEASURES: Infant infections averted, infant deaths, infant disabilities, costs, and societal benefits of healthy infants. RESULTS: A screening strategy using the new polymerase chain reaction test generates a net benefit of $7 per birth when compared with the maternal risk-factor strategy. For every 1 million births, 80 700 more women would receive antibiotics, 884 fewer infants would become infected with early-onset group B streptococci, and 23 infants would be saved from death or disability. The polymerase chain reaction-based strategy generates a net benefit of $6 per birth when compared with the 35- to 37-week prenatal culture strategy and results in fewer maternal courses of antibiotics (64 080 per million births), fewer perinatal infections with early-onset group B streptococci (218/million), and a reduction in 6 infant deaths and severe infant disability per million births. The benefits hold over a wide range of assumptions regarding key factors in the analysis. CONCLUSIONS: Although additional clinical trials are needed to establish the accuracy of this new polymerase chain reaction test, initial studies suggest that strategies using this test will be superior to the other 2 strategies. Using the rapid polymerase chain reaction test becomes less attractive as the cost of the test increases. The test's greatest strengths lie in its ability to identify women and infants at risk at the time of labor, thereby decreasing the number of false-positives and false-negatives seen with the other 2 strategies and allowing for more accurate and effective intrapartum prophylaxis.
Cost-Benefit Analysis↗
Costs and benefits of prenatal screening for cystic fibrosis.
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Abortion, Eugenic↗
Performance of the RAND appropriateness criteria.
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Cataract Extraction↗
Invariance and inconsistency in utility ratings.
PURPOSE: To assess utilities of composite health states for dependence in activities of daily living (ADLs) for invariance (i.e., when subjects provide a utility of 1 for all health states) and order inconsistency (i.e., when subjects order their utilities such that their utility for a combination of ADL dependencies is greater than their utility for any subset of the combination). METHODS: Each of the 400 subjects, age 65 y and older, enrolled in one of several regional medical centers of the Kaiser Permanente Medical Care Program of Northern California and provided standard-gamble utilities for single ADL dependencies (e.g., bathing, dressing, continence) and for dependence in 8 other combinations of ADL dependencies. For order-inconsistent responses, the authors calculated the maximum magnitude of inconsistency as the maximum difference between the utility for the combined ADL dependence health state and that of its inconsistent subset. RESULTS: A total of 76 subjects (19%) gave a utility of 1.0 for all health states presented to them; 19 (5%) gave the same utility other than 1.0 for all health states; 130 (33%) gave at least 1 utility < 1.0 and had no order inconsistencies; and 175 (44%) had at least 1 order inconsistency. Invariance was associated with a Mini-Mental Status Examination score < 28.6 (P = 0.01), with education < 12 y (P = 0.004), with race/ethnicity other than non-Hispanic White/Caucasian (P = 0.001), and with shorter time spent on the utility elicitation task (P < 0.0001). Among the inconsistent subjects, 69% had a maximal magnitude of inconsistency that was within 1 standard deviation of the mean utilities. The maximal magnitude of inconsistency was associated with longer time spent on the elicitation task (P < 0.0001) and race/ethnicity other than non-Hispanic White/Caucasian (P = 0.005). The mean (s) utility for dependence in continence among consistent subjects who were not invariant (0.88 [0.24]) was higher than among inconsistent subjects (0.80 [0.27]; P = 0.01). CONCLUSIONS: Invariance and order inconsistencies in utility ratings for complex health states occur frequently. Utilities of consistent subjects may differ from those of inconsistent subjects. Utility assessments should attempt to measure and report these patterns.
Activities of Daily Living↗
Training synergies between medical informatics and health services research: successes and challenges.
Stanford's two decades of success in linking medical informatics and health services research in both training and investigational activities reflects advantageous geography and history as well as natural synergies in the two areas. Health services research and medical informatics at Stanford have long shared a quantitative, analytic orientation, along with linked administration, curriculum, and clinical activities. Both the medical informatics and the health services research curricula draw on diverse course offerings throughout the university, and both the training and research overlap in such areas as outcomes research, large database analysis, and decision analysis/decision support. The Stanford experience suggests that successful integration of programs in medical informatics and health services research requires areas of overlapping or synergistic interest and activity among the involved faculty and, hence, in time, among the students. This is enhanced by a mixture of casual and structured contact among students from both disciplines, including social interactions. The challenges to integration are how to overcome any geographic separation that may exist in a given institution; the proper management of relationships with those sub-areas of medical informatics that have less overlap with health services research; and the need to determine how best to exploit opportunities for collaboration that naturally occur.
California↗
Evidence-based guidelines as a foundation for performance incentives.
Clinical guidelines, which increasingly build upon impartial analysis of evidence from well-designed studies, have become highly credible sources of information about what forms of care are effective. Consequently, they are attractive as foundations for performance incentives. Unfortunately, they are often complex, and frequently it is infeasible to gather the information required to assess compliance with guidelines at reasonable cost. I discuss the problems in implementing evidence-based guidelines and steps that could be taken to make them more useful as a basis for performance measurement.
Costs and Cost Analysis↗
Cost-effectiveness and evidence evaluation as criteria for coverage policy.
Private health plans and government health insurance programs in the United States base their coverage decisions on evidence criteria, rather than explicit cost-effectiveness criteria. As health spending continues to grow rapidly, however, approaches to coverage policy that ignore costs fail to meet the needs of consumers, employers, health plans, and federal and state governments. I describe the role of evidence-based criteria in formal coverage decision making and contrast the ways that these criteria differ from cost-effectiveness criteria. Finally, I discuss options for incorporating considerations of cost-effectiveness into coverage policy and other aspects of benefit design.
Cost-Benefit Analysis↗