Cost sharing and the use of ambulatory mental health services.
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Ambulatory Care↗
Biomedical subjects
N Duan
Publications and source records attributed to N Duan.
Some interim results from a controlled trial of cost sharing in health insurance.
A total of 7706 persons are participating in a controlled trial of alternative health-insurance policies. Interim results indicate that persons fully covered for medical services spend about 50 per cent more than do similar persons with income-related catastrophe insurance. Full coverage leads to more people using services and to more services per user. Both ambulatory services and hospital admissions increase. Once patients are admitted to the hospital, however, expenditures per admission do not differ significantly among the experimental insurance plans. In addition, hospital admissions for children do not vary by plan. The income-related cost sharing in the experimental plans affects expenditure by different income groups similarly, but adults' total expenditure varies more than children's. Sufficient data are not available on whether higher use by persons with free care reflects overuse, or whether lower use by those with income-related catastrophe coverage reflects underuse. Both may well be true.
Ambulatory Care↗
The Quality Improvement for Depression collaboration: general analytic strategies for a coordinated study of quality improvement in depression care.
It is difficult to evaluate the promise of primary care quality-improvement interventions for depression because published studies have evaluated diverse interventions by using different research designs in dissimilar populations. Preplanned meta-analysis provides an alternative to derive more precise and generalizable estimates of intervention effects; however, this approach requires the resolution of analytic challenges resulting from design differences that threaten internal and external validity. This paper describes the four-project Quality Improvement for Depression (QID) collaboration specifically designed for preplanned meta-analysis of intervention effects on outcomes. This paper summarizes the interventions the four projects tested, characterizes commonalities and heterogeneity in the research designs used to evaluate these interventions, and discusses the implications of this heterogeneity for preplanned meta-analysis.
Adult↗
A diabetes-specific measure of patient desire to participate in medical decision making.
PURPOSE: The goal of this study was to develop a diabetes-specific scale of patient desire to participate in medical decision making (DPMD) and examine its internal consistency reliability, stability, and validity (content, discriminant, convergent, and construct). METHODS: In a cross-sectional study, 65 patients with type 2 diabetes from a teaching hospital's general medical clinic were interviewed at baseline and 2 weeks later to measure their DPMD scores. Data were collected on demographic/clinical features, health value, social support, desire to make a final decision, and value of patient autonomy. RESULTS: Of the 11 DPMD items, 2 distinct factors emerged representing desire for discussion and desire for information. The DPMD scale had high internal consistency reliability, was stable over 2 weeks and demonstrated good content validity. DPMD scale items were more correlated with each other than with health value or social support. Overall, patients who obtained diabetes education reported greater desire to participate in decisions. Younger patients had a greater overall desire for discussion. The DPMD desire for discussion subscale correlated with patients' desire to make the final treatment decision but not with patients' value of autonomy. CONCLUSIONS: The DPMD is a brief, reliable, valid measure for assessing patient desire to participate in diabetes medical decision making.
Attitude to Health↗
A quantitative definition of exposure and related concepts.
This paper develops a unified theoretical framework for understanding exposure to environmental pollutants and other agents. It reviews the scientific literature to describe the many diverse and often confusing ways in which the term "exposure" is being used. Using six criteria proposed for a useful framework, a set of quantitative definitions, which encompass and expand upon existing definitions, is developed. After "agent" (e.g., a pollutant) and "target" (e.g., a person's hand) are defined, "exposure" is defined as the contact between an agent and a target. An "instantaneous point exposure" is defined as the joint occurrence of two events: 1) point i of a target is located at (xi, yi, zi) at time t, and 2) an agent of concentration Ci is present at location (xi, yi, zi) at time t. It is shown that the definition of instantaneous point exposure is fundamental in that all other functions of exposure with respect to space or time-such as the average exposure and the integrated exposure-can be derived from it. Because exposure and dose are closely related and often confused, our framework also includes a general definition of dose that is consistent with common usage. Finally, the definitions in this unified theoretical framework are shown to apply to inhalation exposure, dermal exposure, and ingestion exposure. In addition to the literature review and the quantitative definitions of exposure, this paper includes a glossary of terms that are proposed to help establish a common language for the exposure sciences.
Carbon Monoxide↗
Combination of direct and indirect approaches for exposure assessment.
We combine two major approaches currently used in human air pollution exposure assessment, the direct approach and the indirect approach. The direct approach measures exposures directly using personal monitoring. Despite its simplicity, this approach is costly and is also vulnerable to sample selection bias because it usually imposes a substantial burden on the respondents, making it difficult to recruit a representative sample of respondents. The indirect approach predicts exposures using the activity pattern model to combine activity pattern data with microenvironmental concentrations data. This approach is lower in cost and imposes less respondent burden, thus is less vulnerable to sample selection bias. However, it is vulnerable to systematic measurement error in the predicted exposures because the microenvironmental concentration data might need to be "grafted" from other data sources. The combined approach combines the two approaches to remedy the problems in each. A dual sample provides both the direct measurements of exposures based on personal monitoring and the indirect estimates based on the activity pattern model. An indirect-only sample provides additional indirect estimates. The dual sample is used to calibrate the indirect estimates to correct the systematic measurement error. If both the dual sample and the indirect-only sample are representative, the indirect estimates from the indirect-only sample is used to improve the precision for the overall estimates. If the dual sample is vulnerable to sample selection bias, the indirect-only sample is used to correct the sample selection bias. We discuss the allocation of the resources between the two subsamples and provide algorithms which can be used to determine the optimal sample allocation. The theory is illustrated with applications to the empirical data obtained from the Washington, DC, Carbon Monoxide (CO) Study.
Air Pollutants↗