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Biomedical subjects

D B Matchar

Publications and source records attributed to D B Matchar.

At least 37 records · Page 2Linked to original sources
PubMed2000

Depression and other determinants of values placed on current health state by stroke patients: evidence from the VA Acute Stroke (VASt) study.

BACKGROUND AND PURPOSE: This prospective study examined the determinants of the utility (value) placed on health status among a sample of patients with acute ischemic and intracerebral hemorrhagic stroke. METHODS: Data were from the VA Acute Stroke (VASt) study, a nationwide prospective cohort of 1073 acute stroke patients admitted at any of 9 Department of Veterans Affairs Medical Center sites between April 1, 1995, and March 31, 1997. The primary outcome was the patient's health status utility as measured by the time-tradeoff method. Data were obtained by telephone interviews at 1, 6, and 12 months and by medical record review. General linear mixed modeling was used to assess the effects of social, psychological, and physical factors on patients' valuations of their current health state. The analysis was confined to the 327 patients who were able to provide self-reports at >/=2 time points. RESULTS: Patients' valuations of their health state status over the initial 12 months after stroke were very stable over time, with only a slight improvement at 6 months, followed by a slight decline at 12 months. In adjusted analyses, living alone, being institutionalized, decreased physical function, and depression were independently associated with lower levels of patient health status utility over time. CONCLUSIONS: Stroke patient health status utilities are relatively stable during the initial year after stroke. In addition to physical function, psychological health and social environment are important determinants of patient health status utility. These factors need to be considered when conducting stroke decision analyses if more accurate conclusions are to be drawn regarding preferred patterns of care.

Acute Disease↗
PubMed2000

Racial variation in initial stroke severity.

BACKGROUND AND PURPOSE: Blacks experience greater morbidity and mortality from stroke than do whites. The degree to which this is due to the severity of the initial stroke is not known. The objective of this study is to determine whether there is a racial difference in initial stroke severity. METHODS: A secondary analysis of a prospective cohort of 984 veterans (29.7% black) admitted to any of 9 geographically diverse Veterans Administration Hospitals for acute stroke between April 1995 and March 1997 was performed. Initial stroke severity was ascertained by using the modified Canadian Neurological Scale (CNS) applied retrospectively to medical record data. Stroke severity, unadjusted and adjusted for covariates, was compared between black and white patients. RESULTS: Blacks had greater initial stroke severity than did whites (mean CNS score 7.96 versus 8.32, respectively; P=0.039), with a 0.5-point difference on the scale corresponding to a single-level decrement in either speech or strength of half of an extremity. This difference persisted with adjustment for other important predictors of stroke severity (P=0. 035). However, there was no significant racial difference in severity when CNS scores were collapsed into a priori clinically relevant categories. CONCLUSIONS: Compared with whites, blacks show greater severity of stroke at hospital admission. It remains uncertain whether the relatively small but significant difference at presentation fully explains the striking racial differences in morbidity and mortality from stroke.

Aged↗
PubMed2000

Racial variation in treatment for transient ischemic attacks: impact of participation by neurologists.

OBJECTIVE: This study evaluates the role of neurologists in explaining African American-white differences in the use of diagnostic and therapeutic services for cerebrovascular disease. DATA SOURCES/STUDY SETTING: Medicare inpatient hospital records were used to identify a random 20 percent sample of patients age 65 and over hospitalized with a principal diagnosis of TIA between January 1, 1991 and November 30, 1991 (n = 17,437). STUDY DESIGN: Medicare administrative data were used to identify five outcome measures: noninvasive cerebrovascular tests, cerebral angiography, carotid endarterectomy, anticoagulant therapy (as proxied by outpatient prothrombin time tests), and the specialty of the attending physician (neurologist versus other specialist). DATA COLLECTION/EXTRACTION METHODS: All Medicare claims were extracted for a 30-day period beginning with the date of admission. PRINCIPAL FINDINGS: Even after adjusting for patient demographics, comorbidity, ability to pay, and provider characteristics, African American patients were significantly less likely to receive noninvasive cerebrovascular testing, cerebral angiography, or carotid endarterectomy, compared with white patients, and to have a neurologist as their attending physician. At the same time, patients treated by neurologists were more likely to undergo diagnostic testing and less likely to undergo carotid endarterectomy. CONCLUSIONS: The findings suggest that African American patients with TIA may have less access to services for cerebrovascular disease and that at least some of this may be attributed to less access to neurologists. More research is needed on how patients at risk for stroke are referred to specialists.

Black or African American↗
PubMed2000

Economics of low-molecular weight heparins.

Low-molecular weight heparins (LMWHs) have become attractive alternatives to standard unfractionated heparin (UFH) for the treatment and prophylaxis of deep vein thrombosis (DVT), and for the management of acute coronary syndrome (ACS). The economic impact of the use of LMWHs has been studied in randomized controlled studies, in demonstration projects in managed care institutions, and in decision models. These studies provide valuable insight into the ways LMWHs can be economically attractive despite higher per unit costs compared with UFH. For the treatment of DVT, the cost benefit of using LMWHs results primarily from the cost shifting from inpatient to outpatient care, and might be limited by the eligibility of patients for outpatient management. In contrast, the attractiveness of LMWHs for ACS and DVT prophylaxis hinges on the increased effectiveness of LMWHs compared with standard UFH.

Antifibrinolytic Agents↗
PubMed1999

Incorporation of patient preferences in the treatment of upper urinary tract calculi: a decision analytical view.

PURPOSE: Patient preferences, or utilities, may be crucial to select an appropriate treatment plan for stone disease. We used decision modeling to understand better patient choices and decision making in the overall management of recurrent nephrolithiasis. MATERIALS AND METHODS: We interviewed 180 consecutive patients with active stone disease. Demographic data and historical experiences with calculi were recorded. Patients were presented with 6 hypothetical clinical scenarios and various treatment options. The standard gamble method was used to obtain utility values for each option. RESULTS: Nephrectomy had the lowest mean utility value of 0.883. Percutaneous nephrolithotomy for severe, moderate and mild pain had utilities of 0.924, 0.932 and 0.947, respectively. Shock wave lithotripsy for the management of mild pain was the most attractive option (mean utility 0.968). The utility for long-term medical therapy was 0.949, which was between that of percutaneous nephrolithotomy and shock wave lithotripsy for mild pain. Patients with a surgical history of stone removal assigned lower utilities to invasive procedures (nephrectomy, percutaneous nephrolithotomy, p <0.05). As the incidence of spontaneous stone passage increased, a higher utility was given to long-term medical therapy (p <0.05). Patients on medical therapy less than 1 year did not appreciate a significant benefit of medical prophylaxis. However, longer compliance with medical management led patients to perceive increasing benefits of continuing such medical treatment (p <0.05). Patients who had undergone stone removal via endoscopic or open surgery also had a higher preference for medical therapy (p <0.05). CONCLUSIONS: Patients who had undergone stone removal wanted to avoid future invasive procedures. They ranked long-term medical therapy below shock wave lithotripsy but above invasive procedures, such as percutaneous nephrolithotomy. Most importantly, patients appreciated the benefits of medical therapy the longer that they complied with specific recommendations. These results support the concept that patients perceive long-term medical therapy to prevent recurrent nephrolithiasis as a desirable treatment option.

Adolescent↗
PubMed1999

Performing cost-effectiveness analysis by integrating randomized trial data with a comprehensive decision model: application to treatment of acute ischemic stroke.

A recent national panel on cost-effectiveness in health and medicine has recommended that cost-effectiveness analysis (CEA) of randomized controlled trials (RCTs) should reflect the effect of treatments on long-term outcomes. Because the follow-up period of RCTs tends to be relatively short, long-term implications of treatments must be assessed using other sources. We used a comprehensive simulation model of the natural history of stroke to estimate long-term outcomes after a hypothetical RCT of an acute stroke treatment. The RCT generates estimates of short-term quality-adjusted survival and cost and also the pattern of disability at the conclusion of follow-up. The simulation model incorporates the effect of disability on long-term outcomes, thus supporting a comprehensive CEA. Treatments that produce relatively modest improvements in the pattern of outcomes after ischemic stroke are likely to be cost-effective. This conclusion was robust to modifying the assumptions underlying the analysis. More effective treatments in the acute phase immediately following stroke would generate significant public health benefits, even if these treatments have a high price and result in relatively small reductions in disability. Simulation-based modeling can provide the critical link between a treatment's short-term effects and its long-term implications and can thus support comprehensive CEA.

Acute Disease↗
PubMed1999

The role of evidence reports in evidence-based medicine: a mechanism for linking scientific evidence and practice improvement.

STUDY QUESTIONS: In this article two related questions are considered: (1) Why isn't evidence-based medicine (EBM) more consistently implemented? and (2) Using the EBM paradigm, by what mechanism can we link evidence reports to concrete practice improvement activities? STUDY DESIGN: To motivate a systematic analysis, answers to these questions are framed within the context of a general conceptual model for practice improvement, using as an example the application of this general model to the question of improving anticoagulation. CONCLUSIONS: The potential role of evidence reports is quite broad and to be most effective, they should (1) be considered as part of a comprehensive strategy for practice improvement and (2) be designed with their customers in mind. A system-based method for using the information from evidence reports involves ultimately suggesting specific practice improvement strategies in which the strategies are defined in terms of (1) a set of functional specifications and (2) a toolbox of implementation options. Such an approach brings to bear the specialized expertise and generalized fund of scientific knowledge used to produce the evidence report, but does so in a way that facilitates local tailoring. That is, while information synthesis should be global, implementation must be local.

Cost-Benefit Analysis↗
PubMed1999

Incidence and occurrence of total (first-ever and recurrent) stroke.

BACKGROUND AND PURPOSE: It has recently been hypothesized that the figure of approximately half a million strokes substantially underestimates the actual annual stroke burden for the United States. The majority of previously reported studies on the epidemiology of stroke used relatively small and homogeneous population-based stroke registries. This study was designed to estimate the occurrence, incidence, and characteristics of total (first-ever and recurrent) stroke by using a large administrative claims database representative of all 1995 US inpatient discharges. METHODS: We used the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project, release 4, which contains approximately 20% of all 1995 US inpatient discharges. Because the accuracy of International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) coding is suboptimal, we performed a literature review of ICD-9-CM 430 to 438 validation studies. The pooled results from the literature review were used to make appropriate adjustments in the analysis to correct for some of the inaccuracies of the diagnostic codes. RESULTS: There were 682 000 occurrences of stroke with hospitalization (95% CI 660 000 to 704 000) and an estimated 68 000 occurrences of stroke without hospitalization. The overall incidence rate for occurrence of total stroke (first-ever and recurrent) was 259 per 100 000 population (age- and sex-adjusted to 1995 US population). Incidence rates increased exponentially with age and were consistently higher for males than for females. CONCLUSIONS: We conservatively estimate that there were 750 000 first-ever or recurrent strokes in the United States during 1995. This new figure emphasizes the importance of preventive measures for a disease that has identifiable and modifiable risk factors and for the development of new and improved treatment strategies and infrastructures that can reduce the consequences of stroke.

Adult↗
PubMed1999

Epidemiology of recurrent cerebral infarction: a medicare claims-based comparison of first and recurrent strokes on 2-year survival and cost.

BACKGROUND AND PURPOSE: Because recurrent strokes will tend to leave patients with greater disability than first strokes, patients with recurrent strokes should have poorer outcomes on average than those with first strokes. The extent of this difference has, however, not yet been estimated with precision. METHODS: Using a random 20% sample of Medicare patients aged 65 years and older admitted with a primary diagnosis of cerebral infarction during calendar year 1991, we used historical data from the previous 4 years to classify patients as having either first or recurrent stroke and followed survival and direct medical costs for 24 months after stroke. First and recurrent stroke groups were compared with the log-rank test (survival) and t test (cost) and also multivariate modeling. RESULTS: Survival from first stroke is consistently better than that for recurrent stroke: 24-month survival was 56.7% versus 48.3%, respectively. Costs were similar for the initial hospital stay and in months 1 to 3 after stroke. During months 4 to 24 after stroke, total costs were higher among those with recurrent stroke by approximately $375/mo across all patients, with this difference being greatest for younger patients and least for patients aged 80 years or older. Most of the difference in total monthly cost was attributable to nursing home utilization (averaging approximately $150/mo) and acute hospitalization (averaging approximately $120/mo). CONCLUSIONS: Patients with recurrent stroke have, on average, poorer outcomes than those with first stroke. To be as accurate as possible, clinical policy analyses should use different estimates of health and cost outcomes for first and recurrent stroke.

Aged↗
PubMed1999

Using outcomes data to identify best medical practice: the role of policy models.

Increasingly, physicians are attempting to incorporate best evidence into their clinical decision making. However, best evidence takes a variety of forms, including clinical trials, cohort studies, administrative data, and patient preference data. Incorporating multiple data sources in a way that informs complex clinical decisions is a substantial analytical challenge. One approach to this challenge is to develop a simulation/decision model that explicitly represents the natural history of disease and the impact of treatments on that natural history. The model should be requisite--that is, sufficient in form to address the decision problem--but not overly complex. Such a model can be of value because it (1) allows a variety of viewpoints to be considered, (2) incorporates the best scientific evidence, and (3) permits sensitivity analyses to evaluate the impact of alternative clinical scenarios and uncertainty in model inputs. The Stroke Prevention Policy Model (SPPM) illustrates this approach. The SPPM is a simulation model designed to predict the best among various treatment alternatives for preventing strokes. Similar models can be applied to treatment outcomes for liver disease.

Benchmarking↗
PubMed1998

Utilities for major stroke: results from a survey of preferences among persons at increased risk for stroke.

BACKGROUND: Patient beliefs, values, and preferences are crucial to decisions involving health care. In a large sample of persons at increased risk for stroke, we examined attitudes toward hypothetical major stroke. METHODS AND RESULTS: Respondents were obtained from the Academic Medical Center Consortium (n = 621), the Cardiovascular Health Study (n = 321 ), and United Health Care (n = 319). Preferences were primarily assessed by using the time trade off (TTO). Although major stroke is generally considered an undesirable event (mean TTO = 0.30), responses were varied: although 45% of respondents considered major stroke to be a worse outcome than death, 15% were willing to trade off little or no survival to avoid a major stroke. CONCLUSIONS: Providers should speak directly with patients about beliefs, values, and preferences. Stroke-related interventions, even those with a high price or less than dramatic clinical benefits, are likely to be cost-effective if they prevent an outcome (major stroke) that is so undesirable.

Adult↗
PubMed1998

Multicenter review of preoperative risk factors for endarterectomy for asymptomatic carotid artery stenosis.

BACKGROUND AND PURPOSE: The benefit of carotid endarterectomy is highly dependent on surgical risk. However, little data are available concerning factors affecting the risk of endarterectomy performed for asymptomatic carotid artery stenosis outside the setting of a randomized controlled trial. The purpose of this study was to analyze the impact of potential preoperative risk factors on the frequency of postoperative complications in patients undergoing the operation for asymptomatic disease in academic medical centers. METHODS: Data regarding postoperative complications were systematically abstracted from the medical records of a random sample of patients who underwent carotid endarterectomy at 12 academic medical centers. RESULTS: Of 1160 procedures reviewed, 463 (40%) were performed for asymptomatic disease. Postoperative stroke or death occurred in 13 (2.8%), and myocardial infarction occurred in 8 (1.7%). The rate of postoperative stroke or death was lower in asymptomatic patients than in those with a history of cerebrovascular symptoms in a different vascular distribution, but the difference was not significant (1.8% versus 4.2%; P=.21). There were no significant differences in these rates based on race, a history of angina, recent myocardial infarction, chronic obstructive pulmonary disease, hypertension, the degree of stenosis of the contralateral or ipsilateral carotid artery, or the presence of angiographically recognized ulceration, intraluminal thrombus, or siphon stenosis in the ipsilateral vessel (chi(2); P>.05). Postoperative stroke or death was more frequent in women (5.3% versus 1.6% in men; P=.02), in those aged 75 years or older (7.8% versus 1.8% in those younger than 75 years; P=.01), and in those with a history of congestive heart failure (8.6% versus 2.3% in those without a history of congestive heart failure; P=.03). The risk of stroke or death was higher in the 16 patients who had carotid endarterectomy performed in combination with coronary artery bypass surgery than in those who had only endarterectomy (18.7% versus 2.1%; P<.001). CONCLUSIONS: The overall risk of postoperative stroke or death was nearly twice that reported by Asymptomatic Carotid Atherosclerosis Study (ACAS) investigators in the setting of a clinical trial but was within acceptable guidelines. Women were at higher postoperative risk than men, which supported ACAS findings. Additional high-risk groups were those aged 75 years or older, those with a history of congestive heart failure, and those undergoing prophylactic endarterectomy for asymptomatic stenosis in combination with coronary surgery. Knowledge of these rates may help to better assess an individual's postoperative risk and therefore the anticipated benefit of surgery.

Aged↗
PubMed1998

The value of stroke prevention and treatment.

An emerging issue in stroke prevention and stroke treatment is that therapies shown to be effective in clinical trials are not being used or are being used suboptimally. One of many explanations relates to cost, ranging from concerns about inappropriate use of societal resources to more immediate concerns of organizations and individuals about their financial well-being. Assessing the cost impact of a new therapy, and thus the financial incentives faced by decision-makers, is crucial to understanding and influencing real-world treatment decisions. Assessing cost in the context of health benefits is the object of cost-effectiveness analysis. A cost-effectiveness analysis typically compares the new treatment with a less efficacious yet less costly alternative. This article provides a brief overview of the cost implications of stroke and stroke-related treatments. The example of stroke prevention is used to illustrate how to calculate an incremental cost-effectiveness ratio and help clarify what makes a treatment an especially good value. Because stroke is tremendously expensive and because severe strokes are especially expensive, treatments to prevent stroke and to diminish stroke disability are likely to be an excellent value.

Cerebrovascular Disorders↗
PubMed1997

The Stroke Prevention Policy Model: linking evidence and clinical decisions.

Simulation models that support decision and cost-effectiveness analysis can further the goals of evidence-based medicine by facilitating the synthesis of information from several sources into a single comprehensive structure. The Stroke Prevention Policy Model (SPPM) performs this function for the clinical and policy questions that surround stroke prevention. This paper first describes the basic structure and functions of the SPPM, concentrating on the role of large databases (broadly defined as any database that contains many patients, regardless of study design) in providing the SPPM inputs. Next, recognizing that the use of modeling continues to be a source of some controversy in the medical community, it discusses the philosophical underpinnings of the SPPM. Finally, it discusses conclusions in the context of both stroke prevention and other complex medical decisions. We conclude that despite the difficulties in developing comprehensive models (for example, the length and complexity of model development and validation processes, the proprietary nature of data sources, and the necessity for developing new software), the benefits of such models exceed the costs of continuing to rely on more conventional methods. Although they should not replace the clinician in decision making, comprehensive models based on the best available evidence from large databases can support decision making in medicine.

Cerebrovascular Disorders↗