The effects of self-assessed health: Dealing with and understanding misclassification bias.

Self-assessed health (SAH) is often used in health econometric models as the key explanatory variable or as a control variable. However, there is evidence questioning its test-retest reliability, with up to 30% of individuals changing their response. Building on recent advances in the econometrics of misclassification, we develop a way to consistently estimate and account for misclassification in reported SAH by using data from a large representative longitudinal survey where SAH was elicited twice. From this we gain new insights into the nature of SAH misclassification and its potential for biasing health econometric estimates. The results from applying our approach to nonlinear models of long-term mortality and chronic morbidities reveal that there is substantial heterogeneity in misclassification patterns. We find that adjusting for misclassification is important for estimating the impact of SAH. For other explanatory variables of interest, we find significant but generally small changes to their estimates when SAH misclassification is ignored.

The impact of Medicare part D on income-related inequality in pharmaceutical expenditure.

BACKGROUND: Income-related inequality measures such as the concentration index are often used to describe the unequal distribution of health, health care access, or expenditure in a single measure. This study demonstrates the use of such measures to evaluate the distributional impact of changes in health insurance coverage. We use the example of Medicare Part D in the United States, which increased access to prescription medications for Medicare beneficiaries from 2006. METHODS: Using pooled cross-sectional samples from the Medical Expenditure Panel Survey for 1997-2011, we estimated income-related inequality in drug expenditures over time using the concentration and generalised concentration indices. A difference-in-differences analysis investigated the change in inequality in drug expenditures, as measured using the concentration index and generalised concentration index, between the elderly (over 65 years) and near-elderly (54-63 years) pre- and post-implementation of Medicare Part D. RESULTS: Medicare Part D increased public drug expenditure while out-of-pocket and private spending fell. Public drug expenditures favoured the poor during all study periods, but the degree of pro-poorness declined in the years immediately following the implementation of Part D, with the poor gaining less than the rich in both relative and absolute terms. Part D also appeared to result in a fall in the pro-richness of private insurance drug expenditure in absolute terms but have minimal distributional impact on out-of-pocket expenditure. These effects appeared to be short lived, with a return to the prevailing trends in both concentration and generalised concentration indices several years following the start of Part D. CONCLUSIONS: The implementation of Medicare Part D significantly reduced the degree of pro-poorness in public drug expenditure. The poor gained less of the increased public drug expenditure than the rich in both relative and absolute terms. This study demonstrates how income-related inequality measures can be used to estimate the impact of health system changes on inequalities in health expenditure and provides a guide for future evaluations.

A systematic review of closure versus medical therapy for preventing recurrent stroke in patients with patent foramen ovale and cryptogenic stroke or transient ischemic attack.

The optimal treatment for secondary prevention in patients who have a patent foramen ovale (PFO) and history of cryptogenic stroke is still uncertain and controversial. In view of this, we performed a systematic review of randomized controlled trials (RCTs) to investigate whether PFO closure was superior to medical therapy for prevention of recurrent stroke or transient ischemic attack (TIA) in patients with PFO after cryptogenic stroke. We searched the Cochrane Central Register of Controlled Trials, Embase, PubMed, Web of Science, and ClinicalTrials.gov. Three randomized controlled trials with a total of 2303 patients were included and analyzed. A fixed-effect model was used by Review Manager 5.2 (RevMan 5.2) software. The pooled risk ratio (RR) of recurrent stroke or TIA was 0.70, with 95% confidence interval (CI) = 0.47 to 1.04, p = 0.08. The results were similar in the incidence of death and adverse events, and the pooled RR was 0.92 (95% CI = 0.34 to 2.45, p = 0.86) and 1.08 (95% CI = 0.93 to 1.26, p = 0.32), respectively. The data of this systematic review did not show superiority of closure over medical therapy for secondary prevention after cryptogenic stroke. Due to some limitations of the included studies, more randomized controlled trials are needed for further investigation regarding this field.