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Biomedical subjects

David B Matchar

Publications and source records attributed to David B Matchar.

At least 37 records · Page 2Linked to original sources
PubMed2004

Alzheimer disease: operating characteristics of PET--a meta-analysis.

PURPOSE: To assess the operating characteristics of positron emission tomography (PET) by using fluorine 18 fluorodeoxyglucose (FDG) in the diagnosis of Alzheimer disease. MATERIALS AND METHODS: Articles published between 1989 and 2003 were identified in the MEDLINE, CINAHL, and HealthSTAR databases. Articles were selected if FDG PET was performed with a dedicated scanner and the resolution was specified, if standard criteria were used for the diagnosis of Alzheimer disease, if at least 12 human subjects with Alzheimer disease were enrolled in the study, if clinical diagnosis or histopathologic findings were used as the reference standard, and if sufficient data were provided to construct a 2 x 2 table. Two reviewers independently abstracted data regarding the operating characteristics (sensitivity and specificity) of PET and evaluated the study quality. A meta-analysis was performed by constructing a summary receiver operating characteristic curve and by combining the sensitivity and specificity values by using a random-effects model. RESULTS: Fifteen articles that met the inclusion criteria showed heterogeneity in sensitivity and specificity estimates that were not related to quality features with no plausible explanations. The summary sensitivity of PET was 86% (95% CI: 76%, 93%), and the summary specificity was 86% (95% CI: 72%, 93%). CONCLUSION: The specificity and sensitivity of FDG PET are limited by both study design and patient characteristics. Therefore, the clinical value of these parameters is uncertain; future research on the use of PET in the diagnosis of Alzheimer disease needs to focus on current limitations to be of practical relevance in clinical settings.

Alzheimer Disease↗
PubMed2004

Testing for von Willebrand disease in women with menorrhagia: a systematic review.

OBJECTIVE: To review the evidence supporting screening of adult women with menorrhagia for von Willebrand disease. DATA SOURCES: MEDLINE search from January 1,1990, to December 31, 2003, for articles in English, using keywords "menorrhagia," "von Willebrand disease," "diagnosis," and "screening," with a hand-search of bibliographies of identified articles, review of published abstracts, and discussion with experts. METHODS OF STUDY SELECTION: One hundred seven articles meeting search criteria were reviewed. Articles included in the study were those that provided primary data on the prevalence of von Willebrand disease in adult women with menorrhagia, quality of life, surgical complications, and the effectiveness of medical therapy in women with menorrhagia and von Willebrand disease and test characteristics of screening tests for von Willebrand disease. TABULATION, INTEGRATION, AND RESULTS: The reported prevalence of von Willebrand disease in women with menorrhagia ranged from 5-20% in 5 published studies. Comparison of results was limited by small sample sizes and large confidence intervals, as well as differences in the definitions of menorrhagia and von Willebrand disease used in the studies. Although menorrhagia in women with known von Willebrand disease has a substantial impact on quality of life, there are no data suggesting that this impact is substantially greater than that of menorrhagia in women without von Willebrand disease. Data on the risk of surgical bleeding in women with von Willebrand disease are limited, with only 3 studies with a total of 29 patients identified. Data on the effectiveness of specific therapies are also limited; only one controlled trial was identified. Of single tests for screening, one study of the ristocetin cofactor assay had a sensitivity of 79% and specificity of 90%. Studies of a test of platelet adhesion and aggregation resulted in pooled sensitivities of 83-94% and specificities of 80-88%; however, significant heterogeneity was present. CONCLUSION: There are inadequate data to justify routine testing for von Willebrand disease in adult women with menorrhagia outside of the research setting.

Diagnostic Tests, Routine↗
PubMed2004

How strong is the relationship between functional status and quality of life among persons with stroke?

The quantitative relationship between functional status and self-reported quality of life is relatively unexamined. As part of the 1-, 6-, and 12-month telephone follow-up of consecutive patients in an observational study of patients with stroke, we found that while higher functional status was associated with better quality of life, this relationship was relatively weak (Spearman correlation <0.25). Patients with similar levels of disability reported quite different qualities of life. Any improvement in quality of life over time was modest at best. Mean utilities for patients with minor stroke were near 0.80, while those for patients with major stroke were near 0.60, the latter figure exceeding previous reports. Quality of life with major stroke may not necessarily be as low as that reported before such a stroke occurs. Quality of life after stroke is heterogeneous and depends on more than just level of physical function.

Activities of Daily Living↗
PubMed2004

Pharmacoeconomics of atrial fibrillation and stroke prevention.

Atrial fibrillation (AF) is a common arrhythmia that significantly increases the risk of stroke by the formation and embolism of left-atrial appendage thrombi. This risk can be substantially reduced with antithrombotic therapies such as aspirin or warfarin. Those with the highest risk receive the most benefit from adjusted-dose warfarin compared with aspirin or low-dose warfarin. Because of its efficacy in reducing strokes, adjusted-dose warfarin has been shown to be cost-effective in several different settings, but mostly for AF patients with at least 1 additional risk factor. Warfarin must be adjusted to international normalized ratios (INRs) within the target range of 2.0 to 3.0 to minimize the risk--as well as the cost--of stroke and bleeding. Subtherapeutic INR values occur commonly, but the consequences are increased risk of stroke and therefore increased costs. Of the several strategies available for managing anticoagulation, the key element to controlling costs is avoiding out-of-range values.

Anticoagulants↗
PubMed2003

Veterans Administration Acute Stroke (VASt) Study: lack of race/ethnic-based differences in utilization of stroke-related procedures or services.

BACKGROUND AND PURPOSE: Race/ethnic-based disparities in the utilization of health-related services have been reported. Data collected as part of the Veterans Administration Acute Stroke Study (VASt) were analyzed to determine whether similar differences were present in patients admitted to Veterans Administration (VA) hospitals with acute ischemic stroke. METHODS: VASt prospectively identified stroke patients admitted to 9 geographically separated VA hospitals between April 1995 and March 1997. Demographic characteristics and all inpatient diagnostic tests/procedures were recorded. Frequencies were compared with chi2 tests. RESULTS: Of 1073 enrolled patients, 775 (white, n=520; nonwhite, n=255, including 226 blacks and 28 Hispanic-Americans) with ischemic stroke were admitted from home. Mean ages (71.0+/-0.6 versus 71.9+/-0.4 years; P=0.25) and Trial of ORG 10172 in Acute Stroke Treatment (TOAST) stroke types (atherothrombotic, 12.9% versus 13.3%; cardioembolic, 16.5% versus 18.0%; lacunar, 26.4% versus 27.1%; other, 1.4% versus 2.0%; unclassified, 42.9% versus 39.6%; P=0.89) for whites versus nonwhites were similar. There were no race/ethnic-based differences in the utilization of brain CT (91.0% versus 92.2%; P=0.58), MRI (36.2% versus 41.6%; P=0.14), transthoracic (52.5% versus 53.7%; P=0.75) or transesophageal echocardiography (10.2% versus 10.6%; P=0.86), 24-hour ECG (3.3% versus 1.6%; P=0.17), carotid ultrasound (64.0% versus 62.0%; P=0.57), carotid endarterectomy (1.5% versus 0.8%; P=0.38), rehabilitation evaluations (71.0% versus 76.5%; P=0.11), speech therapy (9.6% versus 12.6%; P=0.21), recreational therapy (3.1% versus 2.0%; P=0.37), or occupational therapy (16.0% versus 19.6%; P=0.20) for whites versus nonwhites, respectively. Angiography was performed less frequently (3.1% versus 8.5%; P=0.01) and ECG more frequently (81.6% versus 73.5%; P=0.01) in nonwhites. The proportions of patients discharged functionally independent were also similar (52% of whites and 50% of nonwhites had discharge Rankin Scale scores of 0, 1, or 2; P=0.63). CONCLUSIONS: Aside from cerebral angiography and ECG, there were no race/ethnic-based disparities in the utilization of a variety of stroke-related procedures and services. The difference in the use of angiography is unlikely to be related to a difference in screening for carotid endarterectomy because there was no difference in the frequency of carotid ultrasonography. The reason ECG was obtained more frequently in nonwhites is uncertain.

Acute Disease↗
PubMed2003

Effects of race and poverty on the process and outcome of inpatient rehabilitation services among stroke patients.

BACKGROUND AND PURPOSE: The greater mortality and residual physical impairments among black stroke patients may be attributable to differential utilization of rehabilitation services. This report examines, within an equal-access healthcare system, racial differences in time to initiation of stroke rehabilitation services and in the trajectory of physical function recovery. METHODS: This study was a secondary analysis of data from an inception cohort of 1073 stroke patients hospitalized between April 1995 and March 1997 and followed up for up to 1 year. Inpatient data came from medical record reviews; follow-up data came from telephone interviews at 1, 6, and 12 months after stroke. The study included consecutive acute ischemic or intracerebral hemorrhagic stroke patients from 9 VA medical centers. The main outcome measures were time to initiation of inpatient rehabilitation services and ability to perform activities of daily living. RESULTS: There were no racial differences in receipt of inpatient rehabilitation services (blacks, 76%; whites, 70%) or in the proportion of patients referred within 3 days of admission (blacks, 43.5%; whites, 42.0%). Among patients who experienced delay in initiation of rehabilitation, only low-income blacks experienced worse functional recovery over 12 months. CONCLUSIONS: Low-income black stroke patients who experience delay in initiation of inpatient rehabilitation have a worse trajectory of functional recovery in the first year after stroke. Poverty-associated factors in the postdischarge setting may explain this phenomenon.

Activities of Daily Living↗
PubMed2003

Do anticoagulation management services improve care? Implications of the Managing Anticoagulation Services Trial.

An Anticoagulation Clinic Service (ACS) has been proposed as one strategy for improving warfarin treatment for patients with atrial fibrillation. In the Managing Anticoagulation Services Trial (MAST), ACSs meeting specifications for high quality care were established in six managed care organizations (MCOs) which had the patients and resources to support this initiative. The trial followed 1165 patients age >or=65 years who had atrial fibrillation as the primary reason for anticoagulation and were enrolled in a participating MCO. The 593 patients in the intervention group saw physicians in a practice cluster which had randomly been assigned to have access to an ACS. These physicians used the ACS on average for about 48% of eligible patients. The 572 patients in the control group received care from physicians in a practice cluster which could not refer patients to the ACS established for the trial but was otherwise unrestricted. The two clusters were compared on the proportion of time warfarin-treated patients were in the target range (2-3) prothrombin time-international normalized ratio (INR) during a 9-month baseline and a 9-month follow-up period. Among patients ( n = 264) for whom data were available for both periods, the changes in percentages of time in the target range were similar in the intervention cluster (baseline: 47.7%; follow-up 55.6%) and in the control cluster (baseline: 49.1%; follow-up: 52.3%; intervention effect: 5%; 95% confidence interval: -5% to 14%; P = 0.32). In both practice clusters, patients had subtherapeutic INR values (1.5 to 1.99) about one fourth of the time. Providing an ACS in a managed care setting did not appear to improve anticoagulation care over the usual care provided at the sites in this trial but could be a reasonable consideration in a practice setting where time in target range is less than 50%. A higher rate of utilization and a more aggressive stance toward subtherapeutic INR values could potentially enhance the effectiveness of an ACS.

Aged↗
PubMed2003

An economic analysis of external hip protector use in ambulatory nursing facility residents.

OBJECTIVE: to evaluate the economic impact of external hip protector use in nursing facilities. DESIGN: cost-effectiveness and cost-utility analyses. MEASUREMENTS: event probabilities, intervention effectiveness, treatment costs, and utility of hip fracture state were determined from peer-reviewed medical literature and public use data. METHODS: a societal perspective with an 18-month time horizon was used. A decision tree model was constructed. Expected cost, effectiveness, and incremental cost-effectiveness ratio were calculated. One and two-way sensitivity analyses and threshold analyses were performed. RESULTS: the strategy of using external hip protectors saves approximately US$300 per subject and adds 0.01 quality adjusted life year over 18 months. The model remains dominant over the entire range of input values for all variables except the cost of hip protectors. At the maximum estimated cost of US$695/subject/18 months, the incremental cost-effectiveness ratio was $30,600/quality adjusted life year. The strategy of using hip protectors was cost saving or cost neutral if the cost of hip protector strategy is <or=US$397/subject/18 months. CONCLUSIONS: using external hip protectors in nursing facilities is cost saving or economically attractive over a wide range of cost and utility assumptions.

Aged↗
PubMed2003

A clinical decision and economic analysis model of cancer pain management.

OBJECTIVE: To design a model that educates clinical decision makers and healthcare professionals about the burden of cancer pain in their individual populations, and that assists them in weighing the effectiveness and cost of different cancer pain management strategies. STUDY DESIGN: Tailored cost-effectiveness analysis using an evidence-based decision analytic model. METHODS: The spreadsheet-based model compares 3 strategies: (1) guideline-based care (GBC), (2) oncology-based care (OBC), and (3) usual care (UC). The model calculates the likelihood of cancer pain in a healthcare population, how effectively that pain is managed, and the average monthly cost of medications plus procedural interventions. Model inputs were derived from published US population demographics, cancer registry data, high-quality studies of cancer pain management, standard reimbursement schedules, and expert opinion. The model permits users to tailor population demographics, strategy effectiveness, and resource costs. RESULTS: Of 100 000 patients with typical US demographics, approximately 508 (0.51%) will have cancer and 205 (0.20%) will suffer from cancer pain. After 1 month, the percentage of cancer pain patients with effective pain management and the cost of each strategy were estimated as follows: (1) GBC, 80% and dollar 579; (2) OBC, 55% and dollar 466; and (3) UC, 30% and dollar 315. Compared with OBC, GBC had an incremental cost-effectiveness ratio of dollar 452 per additional patient relieved of cancer pain. Compared with UC, OBC had an incremental cost-effectiveness ratio of dollar 601 per additional patient relieved of cancer pain. CONCLUSION: Guideline-based cancer pain management leads to improved pain control with modest increases in resource use.

Algorithms↗
PubMed2002

Immunization and MS [RETIRED]: a summary of published evidence and recommendations.

OBJECTIVE: To review the risk of MS exacerbations after infectious episodes potentially preventable by vaccination, and the risks and benefits of immunizing patients with MS. METHODS: The authors searched MEDLINE (1966 to January 2001; U.S. National Library of Medicine, Bethesda, MD), HealthSTAR, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) database (Cinahl Information Systems, Glendale, CA) for English-language articles. Each study was summarized and rated for quality of evidence. Then feasible data were pooled and analyzed in meta-analysis. RESULTS: The risk of contracting common infectious diseases in patients with MS is not well established. There is strong evidence for an increased risk of MS exacerbations during weeks around an infectious episode. There is strong evidence against an increased risk of MS exacerbation after influenza immunization. There is no evidence that hepatitis B, varicella, tetanus, or Bacille Calmette-Guerin vaccines increase the risk of MS exacerbations. Insufficient evidence was found for other vaccines. CONCLUSIONS: Evidence supports 1) strategies to minimize the risk of acquiring infectious diseases that may trigger exacerbations of MS; and 2) the safety of using influenza, hepatitis B, varicella, tetanus, and Bacille Calmette-Guerin (BCG) vaccines in patients with MS.

Communicable Disease Control↗
PubMed2002

Economic analysis of influenza vaccination and antiviral treatment for healthy working adults.

BACKGROUND: Physicians have several treatment options for influenza, including vaccination and various antiviral therapies. However, the optimal influenza prevention and treatment strategy is unknown. OBJECTIVE: To compare the relative health values of contemporary treatment strategies for influenza in a healthy sample of working adults. DESIGN: Cost-benefit analysis using a decision model. DATA SOURCES: Previously published data. TARGET POPULATION: Healthy employed adults 18 to 50 years of age. TIME HORIZON: A complete influenza season. PERSPECTIVE: Societal. INTERVENTIONS: Eight treatment options (yes or no) based on the possible combinations of vaccination and antiviral therapy (rimantadine, oseltamivir, or zanamivir or no treatment) should infection develop. OUTCOME MEASURES: Cost in U.S. dollars, including the value of symptom relief and medication side effects, which was assigned a monetary value through a conjoint analysis that used a "willingness-to-pay" approach. RESULTS: In the base-case analysis, all strategies for influenza vaccination had a higher net benefit than the nonvaccination strategies. Vaccination and use of rimantadine, the most cost-beneficial strategy, was $30.97 more cost-beneficial than nonvaccination and no use of antiviral medication. The health benefits of most antiviral treatments equaled or exceeded their costs for most scenarios. The choice of the most cost-beneficial antiviral strategy was sensitive to the prevalence of influenza B and to the comparative workdays gained by each antiviral therapy. CONCLUSIONS: Vaccination is cost-beneficial in most influenza seasons in healthy working adults. Although the benefits of antiviral therapy for persons with influenza infection appear to justify its cost, head-to-head trials of the various antiviral therapies are needed to determine the optimal treatment strategy.

Acetamides↗
PubMed2002

Improving the quality of anticoagulation of patients with atrial fibrillation in managed care organizations: results of the managing anticoagulation services trial.

Randomized trials have indicated that well-managed anticoagulation with warfarin could prevent more than half of the strokes related to atrial fibrillation. However, many patients with atrial fibrillation who are eligible for this therapy either do not receive it or are not maintained within an optimal prothrombin time-international normalized ratio (INR) range. We sought to determine whether an anticoagulation service within a managed care organization would be a feasible alternative for providing anticoagulation care. We performed a multi-site randomized trial in six large managed care organizations in the United States. Subjects were aged 65 years or older and had nonvalvular atrial fibrillation. At each site, physician practices were divided into two geographically defined practice clusters; each site was randomly assigned to have one intervention and one control cluster. The intervention cluster received an anticoagulation service that satisfied specifications for high-quality anticoagulation care and was coordinated through the managed care organization. Control clusters continued with their usual provider-based care. We measured the proportion of time that warfarin-treated patients in each of the clusters (intervention and control) were in the target range for the INR at baseline, and again during a follow-up period. Five of the six selected sites succeeded at developing an anticoagulation service. Patients in the intervention and control clusters had similar demographic characteristics, contraindications to warfarin, and risk factors for stroke. Among patients (n = 144 in the intervention clusters; n = 118 in the control clusters) for whom data were available during the baseline and follow-up periods, the changes in percentages of time in the target range were similar for those in the intervention clusters (baseline: 47.7%; follow-up: 55.6%) and in the control clusters (baseline: 49.1%; follow-up: 52.3%; intervention effect: 5%; 95% confidence interval: -5% to 14%; P = 0.32). Although it was feasible in a managed care organization to implement anticoagulation services that were tailored to local circumstances, provision of this service did not improve anticoagulation care compared with usual care. The effect of the anticoagulation service was limited by the utilization of the service, the degree to which the referring physician supports strict adherence to recommended target ranges for the INR, and the ability of the anticoagulation service to identify and to respond to out-of-range values promptly.

Aged↗
PubMed2002

Management of uterine leiomyomata: what do we really know?

OBJECTIVE: To systematically review the literature on the surgical and nonsurgical management of uterine leiomyomata. DATA SOURCES: Published literature in English on the management of uterine leiomyomata published from 1975 through 2000 was identified in MEDLINE, CINAHL, CancerLit, EMBASE, HealthSTAR, and the Cochrane Database of Systematic Reviews. Search terms included "leiomyomata," "fibroids," "hysterectomy," and "myomectomy." STUDY SELECTION: Study designs considered included controlled trials, prospective trials with historical controls, prospective or retrospective cohort studies, and series with at least 20 cases. Original research studies or relevant reviews were included if the study population included women with uterine leiomyomata, and data were provided relevant to one or more of nine prespecified research questions. TABULATION, INTEGRATION, AND RESULTS: Inconsistency in reporting of severity of symptoms, uterine anatomy, and response to therapy prevented meaningful comparison of studies in most cases, and prevented performance of meta-analysis in all cases. This was true of both surgical and nonsurgical treatments. CONCLUSION: The available evidence on the management of uterine leiomyomata is of poor quality. Patients, clinicians, and policymakers do not have the data needed to make informed decisions about appropriate treatment. Given the prevalence of this condition and its substantial impact on women's lives, obtaining these data should be a high research priority.

Adult↗