Managing oral anticoagulant therapy.
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Administration, Oral↗
Biomedical subjects
D Matchar
Publications and source records attributed to D Matchar.
Can continuous quality improvement be assessed using randomized trials? [see comment].
STUDY QUESTION: Continuous quality improvement (CQI) has been implemented at least to some degree in many health care settings, yet randomized controlled trials (RCTs) of CQI are rare. We ask whether, when, and how RCTs of CQI might be designed. STUDY DESIGN: We consider two applications of CQI: as a general philosophy of management and (by analogy with the use of conceptual models from the behavioral sciences) as a conceptual model for developing specific interventions. The example of warfarin therapy for stroke prevention among patients with atrial fibrillation is used throughout. PRINCIPAL FINDINGS: While it is impractical to use RCTs to study CQI as a general management philosophy, RCT methodology is appropriate for studying CQI as a conceptual model for generating interventions. RCTs of CQI might be considered when the process change under consideration is very large, its implications (e.g., in terms of cost, outcomes of care, etc.) are very great, and the best approach is uncertain. When designing RCTs of CQI, critical decisions include (1) the unit of randomization; (2) whether the focus is on CQI as a method for generating interventions or, instead, is on specific interventions in and of themselves; and (3) the flexibility available to local personnel to modify the intervention's operational details. CONCLUSIONS: RCTs of CQI as a conceptual model for generating interventions are feasible.
Anticoagulants↗
Race, presenting signs and symptoms, use of carotid artery imaging, and appropriateness of carotid endarterectomy.
BACKGROUND AND PURPOSE: We sought to determine whether there are racial differences in use of carotid artery imaging after controlling for clinical factors and to ascertain racial differences in presenting signs and symptoms and overall appropriateness for carotid endarterectomy (CE). METHODS: We performed a retrospective cohort study of 803 patients older than 45 years, hospitalized between 1991 and 1994 at any of 4 Veterans Affairs Medical Centers, with a discharge diagnosis of transient ischemic attack or ischemic stroke. Clinical data were abstracted from the medical record, including presenting symptoms, diagnostic test results, and use of surgical procedures. Appropriateness for CE was determined according to RAND criteria. RESULTS: Black patients were more likely than white patients to present with stroke (78% versus 55%) but less likely to present with transient ischemic attack (22% versus 45%; P=0.001). There was no racial difference in medical comorbidity or preoperative risk. Black patients were less likely to have an imaging study of their carotid arteries (67% versus 79%; P=0.001). Race remained an independent predictor of imaging after adjustment for clinical factors (odds ratio=1.50; 95% CI, 1.06 to 2.13). Because of higher prevalence of significant carotid artery stenosis, whites were significantly more likely than blacks to be assessed as appropriate candidates for surgery with the use of RAND criteria (18% versus 4%; P=0.001). CONCLUSIONS: Use of carotid artery imaging, a critical step in determining eligibility for CE, is influenced by the patient's race after controlling for clinical presentation. Adjustment for appropriateness of CE reduces but does not eliminate the importance of race.
Black or African American↗
Determining clinically important differences in health status measures: a general approach with illustration to the Health Utilities Index Mark II.
The objective of this article was to describe and illustrate a comprehensive approach for estimating clinically important differences (CIDs) in health-related quality-of-life (HR-QOL). A literature review and pilot study were conducted to determine whether effect size-based benchmarks are consistent with CIDs obtained from other approaches. CIDs may be estimated based primarily upon effect sizes, supplemented by more traditional anchor-based methods of benchmarking (i.e. direct, cross-sectional or longitudinal approaches). A literature review of articles discussing CIDs provided comparative data on effect sizes for various chronic conditions. A pilot study was then conducted to estimate the minimum CID of the Health Utilities Index (HUI) Mark II, and to compare the observed between-group differences observed in a recent randomised trial of an acute stroke intervention with this benchmark. The use of standardised effect size benchmarks has a number of advantages-for example, effect sizes are efficient, widely accepted outside HR-QOL, and have well accepted benchmarks based upon external anchors. In addition, our literature review and pilot study suggest that effect size-based CID benchmarks are similar to those which would be obtained using more traditional methods. For most HR-QOL instruments, we do not know the changes in score which constitute CIDs of various magnitudes. This makes interpretation of HR-QOL results from clinical trials difficult, and having a benchmarking process which is relatively straightforward would be highly desirable.
Clinical Trials as Topic↗
Understanding racial variation in the use of carotid endarterectomy: the role of aversion to surgery.
Previous studies indicate that African-American patients undergo carotid endarterectomy at one fourth the rate of white patients. This study was undertaken to determine if differences in aversion to carotid endarterectomy might account for some of the racial difference in utilization of this procedure. A sample of 185 African-American and white patients was selected from a cohort of patients hospitalized for stroke or transient ischemic attack at four Veterans Affairs medical centers. Of these patients, 115 (62%) were able to be contacted by telephone and 95 (83%) agreed to be interviewed. The interview included assessments of functional status, patient preferences for their current health status, and risk aversion to a hypothetical carotid endarterectomy. Patients from both racial groups were similar in age, marital status, level of education, and comorbid medical illnesses. All respondents were male. Functional status for both groups was high and not statistically different. There were no significant racial differences in patients' perceptions of their current health state. However, African-American patients expressed more aversion to the hypothetical surgery than whites. The median excess risk of death accepted to avoid surgery was 20% for African Americans versus 2.5% for whites. These results indicate that racial differences in the utilization of carotid endarterectomy may be due in part to differences in patients' levels of aversion to this surgery.
Black or African American↗
Health status of individuals with mild stroke.
BACKGROUND AND PURPOSE: Diminished quality of life and limitations in higher levels of physical functioning are often underestimated in stroke and are not fully captured by measures such as the Barthel Index and the Rankin Outcome Scale. This study used additional measures to assess the health status of 304 persons with mild stroke and to compare these individuals with 184 persons with transient ischemic attack and 654 persons without history of stroke/transient ischemic attack but at elevated risk for stroke (asymptomatic group). METHODS: Subjects were recruited from the Academic Medical Center Consortium (inpatients), the Cardiovascular Health Study (population-based sample of community-dwelling persons 65 years and older), and United HealthCare (inpatients and outpatients typically younger than 65 years). Subjects were interviewed by telephone or in person to assess activities of daily living (Barthel Index), depression (Center for Epidemiological Studies Depression Scale), health status (MOS-36), and utility for current health state. RESULTS: Most respondents were independent on all Barthel items. The stroke group was more impaired on the MOS-36 than the asymptomatic group but similar to the group with transient ischemic attack. Health-related quality of life was lowest for persons with stroke. While symptom status and Barthel Index score were the strongest predictors of health status, the Barthel Index showed a consistent ceiling effect when compared with the physical function subscale of the MOS-36. CONCLUSIONS: The consequences of even mild stroke affect all dimensions of health except pain. Standardized assessment of persons with stroke must evaluate across the entire continuum of health-related functions.
Age Distribution↗
Cost-effective models for flutamide for prostate carcinoma patients: are they helpful to policy makers?
BACKGROUND: More than 50,000 male patients received hormonal therapy for metastatic prostate carcinoma in 1995. Nonsteroidal antiandrogens, such as flutamide, when used in conjunction with castration, are effective in prolonging the time to progression of disease and survival. Only one-third of newly diagnosed patients with metastatic prostate carcinoma receive flutamide. Physicians may be reluctant to prescribe flutamide because of quality of life, toxicity, and cost considerations. METHODS: Physician focus groups evaluated quality of life factors for metastatic prostate cancer. RESULTS: Using quality of life estimates with the National Cancer Institute's (NCI) 0036 clinical trial results, our revised model of flutamide use predicted that, for minimal disease, survival increased by 4.33 quality adjusted months (QAMs) at an incremental cost of $25,000 per quality adjusted life year (QALY) saved and for severe disease, survival increased by 4.11 QAM at a cost of $18,000 per QALY saved. However, if quality of life estimates are used in conjunction with the Prostate Cancer Trialists' Collaborative Group (PCTCG) meta-analysis estimates, survival increased by 2.1 QAM at an incremental cost of $41,000 per QALY saved for persons with severe disease and increased by 2.6 QAM at an incremental cost of $53,700 per QALY saved for persons with minimal disease. CONCLUSIONS: Using NCI 0036 trial data, flutamide has an incremental cost-effectiveness more favorable than most therapies, while estimates based on the PCTCG found a less favorable outcome for the drug. Concerns about out-of-pocket expenditures and efficacy limit flutamide utilization; quality of life considerations are less cogent.
Androgen Antagonists↗
Cost-effectiveness of collecting routine cytologic specimens during fiberoptic bronchoscopy for endoscopically visible lung tumor.
STUDY OBJECTIVE: Fiberoptic bronchoscopy is the most common modality used to diagnose endobronchial carcinoma. Collection of brushing and washing specimens for cytology is common during bronchoscopy for endobronchial abnormality, but it is unknown if collection of these specimens is cost-effective. DESIGN: Retrospective review of a computerized database with cost-effectiveness analysis. SETTING: Tertiary care medical center. PATIENTS: Two hundred one patients undergoing bronchoscopy for endobronchial lung tumor. INTERVENTION: All patients in the study underwent fiberoptic bronchoscopy that included forceps biopsies, washings, and brushings. In addition to analyzing the sensitivity of forceps-biopsy, washings, and brushings at diagnosing malignancy, we analyzed the cost-effectiveness of three potential specimen collection strategies. These strategies were (1) collection of both washings and brushings in addition to forceps biopsy specimen, (2) collection of either washings or brushings in addition to forceps biopsy specimen, and (3) collection of forceps biopsy specimen only. MEASUREMENTS AND RESULTS: The sensitivity of bronchoscopy, including biopsy, washing, and brushing is 85.3% (95% confidence interval [CI], 80.1 to 90.5%). The sensitivity of forceps biopsy is 80.8% (95% CI, 75.0 to 86.6%). The addition of washings and brushings increases the sensitivity of bronchoscopy from 80.8 to 85.3% (McNemar's p = 0.01). Cost-effectiveness analysis reveals that forceps biopsy plus washing or brushing has a marginal cost-effectiveness ratio of $308 per reduced-quality day avoided compared with forceps alone. Adding an additional cytology specimen has a marginal cost-effectiveness ratio of $5,500 per reduced-quality day avoided. CONCLUSIONS: There is a modest but definite increase in the sensitivity of bronchoscopy in diagnosing endobronchial cancer with the addition of washings and brushings for cytology. Cost-effectiveness analysis reveals that collection of either washings or brushings is probably the best strategy.
Bronchoscopy↗
Management of atrial fibrillation.
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Atrial Fibrillation↗
Measurement of motor recovery after stroke. Outcome assessment and sample size requirements.
BACKGROUND AND PURPOSE: The purpose of this study was to analyze recovery of motor function in a cohort of patients presenting with an acute occlusion in the carotid distribution. Analysis of recovery patterns is important for estimating patient care needs, establishing therapeutic plans, and estimating sample sizes for clinical intervention trials. METHODS: We prospectively measured the motor deficits of 104 stroke patients over a 6-month period to identify earliest measures that would predict subsequent motor recovery. Motor function was measured with the Fugl-Meyer Assessment. Fifty-four patients were randomly assigned to a training set for model development; 50 patients were assigned to a test set for model validation. In a second analysis, patients were stratified on basis of time and stroke severity. The sample size required to detect a 50% improvement in residual motor function was calculated for each level of impairment and at three points in time. RESULTS: At baseline the initial Fugl-Meyer motor scores accounted for only half the variance in 6-month motor function (r2 = 0.53, p less than 0.001). After 5 days, both the 5-day motor and sensory scores explained 74% of the variance (p less than 0.001). After 30 days, the 30-day motor score explained 86% of the variance (p less than 0.001). Application of these best models to the test set confirmed the results obtained with the training set. Sample-size calculations revealed that as severity and time since stroke increased, sample sizes required to detect a 50% improvement in residual motor deficits decreased. CONCLUSIONS: Most of the variability in motor recovery can be explained by 30 days after stroke. These findings have important implications for clinical practice and research.
Activities of Daily Living↗
Cost-effectiveness evaluation of measles immunization strategies on a college campus.
Since live rubeola vaccine became available in 1963, routine immunization of children at age 15 months has been the recommended strategy for eliminating measles in the United States. However, due to increasing measles outbreaks, especially among previously immunized populations, the Immunization Practices Advisory Committee (ACIP) recently recommended modifying the one-dose measles vaccination policy to a two-dose schedule, one at 15 months and one at age 5 or 6 years. To address the present college population, ACIP recommended vaccinating all college students who lack proof of immunity. We used the methods of decision analysis to examine the cost effectiveness of implementing such a program in a specific college population, namely, students at the University of California at Los Angeles (UCLA). We developed a model to examine three possible vaccination strategies: "wait," "screen," and "vaccinate all." Estimates of probabilities and cost were derived from several outbreaks at UCLA as well as statewide data. In the baseline case, the least expensive strategy is to wait until an outbreak occurs before implementing a vaccination program. The additional cost incurred by screening per measles case avoided is $122,871. However, using sensitivity analysis, we found that the overall cost of elective vaccination strategies is driven by the cost of the vaccine itself. If vaccine could be provided at a nominal cost to the university, a strategy of vaccinating all students without proof of immunity (by either history of two vaccinations or positive titer) would provide the high level of immunity needed to prevent outbreaks and still be most cost effective ($16,644 per measles case avoided).
Cost-Benefit Analysis↗
Cost-effectiveness models of clinical trials of new pharmaceuticals for AIDS-related Pneumocystis carinii pneumonia: are they helpful to policy makers?
BACKGROUND: Pneumocystis carinii pneumonia (PCP) has been the most common and most costly complication of acquired immunodeficiency syndrome (AIDS). Because of concern over the high costs of care for persons with AIDS, policy makers have instituted a number of new measures to encourage cost-effectiveness. Although the clinical efficacy of new pharmaceutical agents is evaluated extensively before approval, comparative trials of a new agent with its major competitor are sometimes not carried out, and estimates of cost-effectiveness are therefore difficult to obtain. METHODS: We describe methodologic issues associated with the development of economic models of new pharmaceutical agents and illustrate these issues with an analysis of second-line therapeutic options for PCP. RESULTS: A new drug, trimetrexate, and the standard second-line therapy, pentamidine, are both inferior to the standard first-line therapy, trimethoprim/sulfamethoxazole, as initial therapy for moderate to severe PCP. However, as many as half of the patients with PCP are either intolerant or refractory to trimethoprim/sulfamethoxazole therapy for PCP. Economic models suggest that, if the two drugs have identical survival rates, then trimetrexate, despite a higher acquisition cost, is both less expensive and more effective in achieving toxicity-free survival than pentamidine in patients who require second-line therapy for PCP. Sensitivity analyses indicate that trimetrexate is less expensive than pentamidine over a wide range of estimates of costs and effectiveness. CONCLUSIONS: To make well-informed therapeutic decisions, policy makers and physicians require head-to-head studies of a new pharmaceutical agent with its major competitor. However, economic models can be used to derive estimates of cost-effectiveness of new pharmaceutical agents when such data are lacking. The interpretation of these models raises general issues related to the perspective of the investigators, study design, estimation of costs of care, rates of response, toxicity, and survival, and generalizability of the results to other settings as well as methodologic issues that are unique to human immunodeficiency virus (HIV) disease. If a comparative trial found better survival rates, then cost-effectiveness models would be of limited usefulness; almost all physicians would use the drug with the higher survival rate.
AIDS-Related Opportunistic Infections↗