Persuasive communication and medical technology assessment.

Assessments of medical technologies with respect to their efficacy, safety, and cost-effectiveness are expected to influence clinical practice, but they are often lost in an avalanche of medical information. We developed a conceptual model that may aid understanding of the potential impact on clinical practice of new medical information in general and assessment information in particular. The model identifies aspects of medical communication that may influence an assessment's subsequent impact, including sources, messages, channels, audiences, and settings. We reviewed the literature on how medical information diffuses to physicians and highlighted those factors likely to heighten physicians' awareness and decisions to incorporate recommended medical advances. We outlined implications for educational interventions and promising research directions.

Effect of cost-sharing on the use of medical services by children: interim results from a randomized controlled trial.

Health care expenditures of 1,136 children whose families participated in a randomized trial, The Rand Health Insurance Experiment, are reported. Children whose families were assigned to receive 100% reimbursement for health costs spent one third more per capita than children whose families paid 95% of medical expenses up to a family maximum. Outpatient use decreased as cost-sharing rose for a variety of use measures: the probability of seeing a doctor, annual expenditures, number of visits per year, and numbers of outpatient treatment episodes. Hospital expenditures did not vary significantly among children insured with varying levels of cost-sharing. Episodes of treatment for preventive care were as responsive to cost-sharing as episodes for acute or chronic illness. The results give no reason not to insure preventive care as liberally as care for acute illness.

Consequences of cost-sharing for children's health.

Do children whose families bear a percentage of their health care costs reduce their use of ambulatory care compared with those families who receive free care? If so, does the reduction affect their health? To answer these questions, 1,844 children aged 0 to 13 years were randomly assigned (for a period of 3 or 5 years) to one of 14 insurance plans. The plans differed in the percentage of their medical bills that families paid. One plan provided free care. The others required up to 95% coinsurance subject to a +1,000 maximum. Children whose families paid a percentage of costs reduced use by up to one third. For the typical child in the study, this reduction caused no significant difference in either parental perceptions of their child's health or in physiologic measures of health. Confidence intervals are sufficiently narrow for most measures to rule out the possibility that large true differences went undetected. Nor were statistically significant differences observed for children at risk of disease. Wider confidence intervals for these comparisons, however, mean that clinically meaningful differences, if present, could have been undetected in certain subgroups.

Evaluating quality-of-life and health status instruments: development of scientific review criteria.

The Medical Outcomes Trust is a depository and distributor of high-quality, standardized, health outcomes measurement instruments to national and international health communities. Every instrument in the Trust library is reviewed by the Scientific Advisory Committee against a rigorous set of eight attributes. These attributes consist of the following: (1) conceptual and measurement model; (2) reliability; (3) validity; (4) responsiveness; (5) interpretability; (6) respondent and administrative burden; (7) alternative forms; and (8) cultural and language adaptations. In addition to a full description of each attribute, we discuss uses of these criteria beyond evaluation of existing instruments and lessons learned in the first few rounds of instrument review against these criteria.

Current methods of the US Preventive Services Task Force: a review of the process.

The U.S. Preventive Services Task Force (USPSTF/Task Force) represents one of several efforts to take a more evidence-based approach to the development of clinical practice guidelines. As methods have matured for assembling and reviewing evidence and for translating evidence into guidelines, so too have the methods of the USPSTF. This paper summarizes the current methods of the third USPSTF, supported by the Agency for Healthcare Research and Quality (AHRQ) and two of the AHRQ Evidence-based Practice Centers (EPCs). The Task Force limits the topics it reviews to those conditions that cause a large burden of suffering to society and that also have available a potentially effective preventive service. It focuses its reviews on the questions and evidence most critical to making a recommendation. It uses analytic frameworks to specify the linkages and key questions connecting the preventive service with health outcomes. These linkages, together with explicit inclusion criteria, guide the literature searches for admissible evidence. Once assembled, admissible evidence is reviewed at three strata: (1) the individual study, (2) the body of evidence concerning a single linkage in the analytic framework, and (3) the body of evidence concerning the entire preventive service. For each stratum, the Task Force uses explicit criteria as general guidelines to assign one of three grades of evidence: good, fair, or poor. Good or fair quality evidence for the entire preventive service must include studies of sufficient design and quality to provide an unbroken chain of evidence-supported linkages, generalizable to the general primary care population, that connect the preventive service with health outcomes. Poor evidence contains a formidable break in the evidence chain such that the connection between the preventive service and health outcomes is uncertain. For services supported by overall good or fair evidence, the Task Force uses outcomes tables to help categorize the magnitude of benefits, harms, and net benefit from implementation of the preventive service into one of four categories: substantial, moderate, small, or zero/negative. The Task Force uses its assessment of the evidence and magnitude of net benefit to make a recommendation, coded as a letter: from A (strongly recommended) to D (recommend against). It gives an I recommendation in situations in which the evidence is insufficient to determine net benefit. The third Task Force and the EPCs will continue to examine a variety of methodologic issues and document work group progress in future communications.

Screening and treating adults for lipid disorders.

CONTEXT: Screening and treatment of lipid disorders in people at high risk for future coronary heart disease (CHD) events has gained wide acceptance, especially for patients with known CHD, but the proper role in people with low to medium risk is controversial. OBJECTIVE: To examine the evidence about the benefits and harms of screening and treatment of lipid disorders in adults without known cardiovascular disease for the U.S. Preventive Services Task Force. DATA SOURCES: We identified English-language articles on drug therapy, diet and exercise therapy, and screening for lipid disorders from comprehensive searches of the MEDLINE database from 1994 through July 1999. We used published systematic reviews, hand searching of relevant articles, the second Guide to Clinical Preventive Services, and extensive peer review to identify important older articles and to ensure completeness. DATA SYNTHESIS: There is strong, direct evidence that drug therapy reduces CHD events, CHD mortality, and possibly total mortality in middle-aged men (35 to 65 years) with abnormal lipids and a potential risk of CHD events greater than 1% to 2% per year. Indirect evidence suggests that drug therapy is also effective in other adults with similar levels of risk. The evidence is insufficient about benefits and harms of treating men younger than 35 years and women younger than 45 years who have abnormal lipids but no other risk factors for heart disease and low risk for CHD events (less than 1% per year). Trials of diet therapy for primary prevention have led to long-term reductions in cholesterol of 3% to 6% but have not demonstrated a reduction in CHD events overall. Exercise programs that maintain or reduce body weight can produce short-term reductions in total cholesterol of 3% to 6%, but longer-term results in unselected populations have found smaller or no effect. To identify accurately people with abnormal lipids, at least two measurements of total cholesterol and high-density lipoprotein cholesterol are required. The role of measuring triglycerides and the optimal screening interval are unclear from the available evidence. CONCLUSIONS: On the basis of the effectiveness of treatment, the availability of accurate and reliable tests, and the likelihood of identifying people with abnormal lipids and increased CHD risk, screening appears to be effective in middle-aged and older adults and in young adults with additional cardiovascular risk factors.

Differences among hospitals in Medicare patient mortality.

Using hospital discharge abstract data for fiscal year 1984 for all acute care hospitals treating Medicare patients (age greater than or equal to 65), we measured four mortality rates: inpatient deaths, deaths within 30 days after discharge, and deaths within two fixed periods following admission (30 days, and the 95th percentile length of stay for each condition). The metric of interest was the probability that a hospital would have as many deaths as it did (taking age, race, and sex into account). Differences among hospitals in inpatient death rates were large and significant (p less than .05) for 22 of 48 specific conditions studied and for all conditions together; among these 22 "high-variation" conditions, medical conditions accounted for far more deaths than did surgical conditions. We compared pairs of conditions in terms of hospital rankings by probability of observed numbers of inpatient deaths; we found relatively low correlations (Spearman correlation coefficients of 0.3 or lower) for most comparisons except between a few surgical conditions. When we compared different pairs of the four death measures on their rankings of hospitals by probabilities of the observed numbers of deaths, the correlations were moderate to high (Spearman correlation coefficients of 0.54 to 0.99). Hospitals with low probabilities of the number of observed deaths were not distributed randomly geographically; a small number of states had significantly more than their share of these hospitals (p less than .01). Information from hospital discharge abstract data is insufficient to determine the extent to which differences in severity of illness or quality of care account for this marked variability, so data on hospital death rates cannot now be used to draw inferences about quality of care. The magnitude of variability in death rates and the geographic clustering of facilities with low probabilities, however, both argue for further study of hospital death rates. These data may prove most useful as a screening mechanism to identify patterns of potentially poor quality of care. Careful choice of the mortality measure used is needed, however, to maximize the probability of identifying those hospitals, and only those hospitals, warranting more in-depth review.

Health policy issues and applications for evidence-based medicine and clinical practice guidelines.

Evidence-based medicine and clinical practice guidelines have become increasingly salient to the international health care community in the 1990s. Key issues in health policy in this period can be categorised as costs and access to care, quality of and satisfaction with care, accountability for value in health care, and public health and education. This paper presents a brief overview of evidence-based medicine and clinical practice guidelines and describes how they are likely to influence health policy. Evidence-based medicine focuses on the use of the best available clinical (efficacy) evidence to inform decisions about patient care; guidelines are statements systematically developed from efficacy and effectiveness research and clinical consensus for practitioners and patients to use in making decisions about appropriate care under different clinical circumstances. Both fields have developed methods for evaluating and synthesising available evidence about the outcomes of alternative health care interventions. They have clear implications for health policy analysts: greater reliance should be placed on scientific evidence, policy decisions should be derived systematically, and health care decisionmaking must allow for the active participation of health care providers, policy makers, and patients or their advocates. The methods and information generated from evidence-based guidelines efforts are critical inputs into health policy analysis and decision-making.

The role of research in setting priorities for health care.

Research of all types plays a fundamental role in setting health care priorities, in part by informing the development of robust clinical practice guidelines. Today's investments in research may make tomorrow's choices about who gets what kinds of care easier, not more difficult. The converse also holds: today's investments in providing care, if made at the significant expense of research, will not make tomorrow's choices about care any easier. In making choices and balancing priorities, the centrality of health services research must be understood. The information necessary to make the hard choices about priorities in health care today may be generated as much, if not more, from investments in this field of inquiry as from equivalent investments in other arenas of scientific endeavour, because of the growing need for information about the effectiveness of health care and in making better use of health resources.

Outcome measurement: concepts and questions.

Outcome measurement-a central concept of quality of care-has both conceptual appeal and limitations as a practical assessment tool. The degree to which outcomes can be directly related to processes of care continues to be especially problematic. I view the continued debate about whether processes or outcomes are the preferable measure of quality as fundamentally unproductive, because both are needed. To strengthen our understanding of both measures in ascertaining quality of care, I suggest that work in four areas is needed: more definitive evidence of process and outcome linkages; stronger relationships between technology assessment and quality assessment; improved reliability and validity of outcome measures as screening tools; and continued development of health status measures.