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220 result(s) for "Zaslavsky, Alan M"
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Balancing Covariates via Propensity Score Weighting
Covariate balance is crucial for unconfounded descriptive or causal comparisons. However, lack of balance is common in observational studies. This article considers weighting strategies for balancing covariates. We define a general class of weights-the balancing weights-that balance the weighted distributions of the covariates between treatment groups. These weights incorporate the propensity score to weight each group to an analyst-selected target population. This class unifies existing weighting methods, including commonly used weights such as inverse-probability weights as special cases. General large-sample results on nonparametric estimation based on these weights are derived. We further propose a new weighting scheme, the overlap weights, in which each unit's weight is proportional to the probability of that unit being assigned to the opposite group. The overlap weights are bounded, and minimize the asymptotic variance of the weighted average treatment effect among the class of balancing weights. The overlap weights also possess a desirable small-sample exact balance property, based on which we propose a new method that achieves exact balance for means of any selected set of covariates. Two applications illustrate these methods and compare them with other approaches.
Physician age and outcomes in elderly patients in hospital in the US: observational study
Objectives To investigate whether outcomes of patients who were admitted to hospital differ between those treated by younger and older physicians.Design Observational study.Setting US acute care hospitals.Participants 20% random sample of Medicare fee-for-service beneficiaries aged ≥65 admitted to hospital with a medical condition in 2011-14 and treated by hospitalist physicians to whom they were assigned based on scheduled work shifts. To assess the generalizability of findings, analyses also included patients treated by general internists including both hospitalists and non-hospitalists.Main outcome measures 30 day mortality and readmissions and costs of care. Results 736 537 admissions managed by 18 854 hospitalist physicians (median age 41) were included. Patients’ characteristics were similar across physician ages. After adjustment for characteristics of patients and physicians and hospital fixed effects (effectively comparing physicians within the same hospital), patients’ adjusted 30 day mortality rates were 10.8% for physicians aged <40 (95% confidence interval 10.7% to 10.9%), 11.1% for physicians aged 40-49 (11.0% to 11.3%), 11.3% for physicians aged 50-59 (11.1% to 11.5%), and 12.1% for physicians aged ≥60 (11.6% to 12.5%). Among physicians with a high volume of patients, however, there was no association between physician age and patient mortality. Readmissions did not vary with physician age, while costs of care were slightly higher among older physicians. Similar patterns were observed among general internists and in several sensitivity analyses.Conclusions Within the same hospital, patients treated by older physicians had higher mortality than patients cared for by younger physicians, except those physicians treating high volumes of patients.
Diagnostic Validity of the Generalized Anxiety Disorder - 7 (GAD-7) among Pregnant Women
Generalized anxiety disorder (GAD) during pregnancy is associated with several adverse maternal and perinatal outcomes. A reliable and valid screening tool for GAD should lead to earlier detection and treatment. Among pregnant Peruvian women, a brief screening tool, the GAD-7, has not been validated. This study aims to evaluate the reliability and validity of the GAD-7. Of 2,978 women who attended their first perinatal care visit and had the GAD-7 screening, 946 had a Composite International Diagnostic Interview (CIDI). The Cronbach's alpha was calculated to examine the reliability. We assessed the criterion validity by calculating operating characteristics. The construct validity was evaluated using factor analysis and association with health status on the CIDI. The cross-cultural validity was explored using the Rasch Rating Scale Model (RSM). The reliability of the GAD-7 was good (Cronbach's alpha = 0.89). A cutoff score of 7 or higher, maximizing the Youden Index, yielded a sensitivity of 73.3% and a specificity of 67.3%. One-factor structure of the GAD-7 was confirmed by exploratory and confirmatory factor analysis. Concurrent validity was supported by the evidence that higher GAD-7 scores were associated with poor self-rated physical and mental health. The Rasch RSM further confirmed the cross-cultural validity of the GAD-7. The results suggest that the Spanish-language version of the GAD-7 may be used as a screening tool for pregnant Peruvian women. The GAD-7 has good reliability, factorial validity, and concurrent validity. The optimal cutoff score obtained by maximizing the Youden Index should be considered cautiously; women who screened positive may require further investigation to confirm GAD diagnosis.
The United States Leads Other Nations In Differences By Income In Perceptions Of Health And Health Care
We examined income gaps in the period 2011-13 in self-assessments of personal health and health care across thirty-two middle- and high-income countries. While high-income respondents were generally more positive about their health and health care in most countries, the gap between them and low-income respondents was much bigger in some than in others. The United States has among the largest income-related differences in each of the measures we studied, which assessed both respondents' past experiences and their confidence about accessing needed health care in the future. Relatively low levels of moral discomfort over income-based health care disparities despite broad awareness of unmet need indicate more public tolerance for health care inequalities in the United States than elsewhere. Nonetheless, over half of Americans felt that income-based health care inequalities are unfair, and these respondents were significantly more likely than their compatriots to support major health system reform-differences that reflect the country's political divisions. Given the many provisions in the Affordable Care Act that seek to reduce disparities, any replacement would also require attention to disparities or risk taking a step backward in an area where the United States is in sore need of improvement.We examined income gaps in the period 2011-13 in self-assessments of personal health and health care across thirty-two middle- and high-income countries. While high-income respondents were generally more positive about their health and health care in most countries, the gap between them and low-income respondents was much bigger in some than in others. The United States has among the largest income-related differences in each of the measures we studied, which assessed both respondents' past experiences and their confidence about accessing needed health care in the future. Relatively low levels of moral discomfort over income-based health care disparities despite broad awareness of unmet need indicate more public tolerance for health care inequalities in the United States than elsewhere. Nonetheless, over half of Americans felt that income-based health care inequalities are unfair, and these respondents were significantly more likely than their compatriots to support major health system reform-differences that reflect the country's political divisions. Given the many provisions in the Affordable Care Act that seek to reduce disparities, any replacement would also require attention to disparities or risk taking a step backward in an area where the United States is in sore need of improvement.
Sleep debt: the impact of weekday sleep deprivation on cardiovascular health in older women
Short sleep duration is associated with increased cardiovascular disease (CVD) risk. However, it is uncertain whether sleep debt, a measure of sleep deficiency during the week compared to the weekend, confers increased cardiovascular risk. Because sleep disturbances increase with age particularly in women, we examined the relationship between sleep debt and ideal cardiovascular health (ICH) in older women. Sleep debt is defined as the difference between self-reported total weekday and weekend sleep hours of at least 2 hours among women without apparent CVD and cancer participating in the Women's Health Stress Study follow-up cohort of female health professionals (N = 22 082). The ICH consisted of seven health factors and behaviors as defined by the American Heart Association Strategic 2020 goals including body mass index, smoking, physical activity, diet, blood pressure, total cholesterol, and glucose. Mean age was 72.1 ± 6.0 years. Compared to women with no sleep debt, women with sleep debt were more likely to be obese and have hypertension (pall < .05). Linear regression models adjusted for age and race/ethnicity revealed that sleep debt was significantly associated with poorer ICH (B = -0.13 [95% CI = -0.18 to -0.08]). The relationship was attenuated but remained significant after adjustment for education, income, depression/anxiety, cumulative stress, and snoring. Sleep debt was associated with poorer ICH, despite taking into account socioeconomic status and psychosocial factors. These results suggest that weekly sleep duration variation, possibly leading to circadian misalignment, may be associated with cardiovascular risk in older women.
Cohort of birth modifies the association between FTO genotype and BMI
Significance Our finding of a significant gene-by-birth-cohort interaction adds a previously unidentified dimension to gene-by-environment interaction research, suggesting that global changes in the environment over time can modify the penetrance of genetic risk factors for diverse phenotypes. This result also suggests that presence (or absence) of a genotype–phenotype correlation may depend on the period of time study subjects were born in, or the historical moment researchers conduct their investigations. A substantial body of research has explored the relative roles of genetic and environmental factors on phenotype expression in humans. Recent research has also sought to identify gene–environment (or g-by-e) interactions, with mixed success. One potential reason for these mixed results may relate to the fact that genetic effects might be modified by changes in the environment over time. For example, the noted rise of obesity in the United States in the latter part of the 20th century might reflect an interaction between genetic variation and changing environmental conditions that together affect the penetrance of genetic influences. To evaluate this hypothesis, we use longitudinal data from the Framingham Heart Study collected over 30 y from a geographically relatively localized sample to test whether the well-documented association between the rs993609 variant of the FTO (fat mass and obesity associated) gene and body mass index (BMI) varies across birth cohorts, time period, and the lifecycle. Such cohort and period effects integrate many potential environmental factors, and this gene-by-environment analysis examines interactions with both time-varying contemporaneous and historical environmental influences. Using constrained linear age–period–cohort models that include family controls, we find that there is a robust relationship between birth cohort and the genotype–phenotype correlation between the FTO risk allele and BMI, with an observed inflection point for those born after 1942. These results suggest genetic influences on complex traits like obesity can vary over time, presumably because of global environmental changes that modify allelic penetrance.
Validating Reports of Chronic Conditions in the Medicare CAHPS Survey
Supplemental Digital Content is available in the text. Background:The Medicare Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey includes items about chronic conditions, health history, and self-rated health. Questions remain about the concordance between patient reports and administrative sources on questions related to health history.Objective:To validate CAHPS measures of chronic conditions against claims-based measures from the Medicare Chronic Conditions Warehouse (CCW).Methods:We linked CAHPS responses from 301,050 fee-for-service Medicare beneficiaries in 2010-2012 with summaries of their claims in the CCW and identified nearest equivalent measures of conditions across sources. We calculated sensitivities and specificities for conditions and estimated regression models to assess the effects of patient characteristics on the sensitivity.Results:The sensitivity of CAHPS measures differed across conditions, ranging from 0.513 for history of stroke to 0.773 for history of cancer. Sensitivity was generally lower for older beneficiaries, those reporting good self-rated health, and those with fair or poor mental health. Specificity was 0.904 or greater for all conditions, up to 0.961 for stroke.Conclusions:Despite difference in timeframes and definitions of conditions, the measured sensitivities demonstrated reasonable validity. Variation in sensitivity is consistent with covariates that either directly measure health severity within a diagnosis or can be construed as a proxy for severity of illness.
Overuse of Colonoscopy for Colorectal Cancer Screening and Surveillance
ABSTRACT BACKGROUND Ongoing efforts to increase colorectal cancer (CRC) screening rates have raised concerns that these exams may be overused, thereby subjecting patients to unnecessary risks and wasting healthcare resources. OBJECTIVE Our aim was to measure overuse of screening and surveillance colonoscopies among average-risk adults, and to identify correlates of overuse. DESIGN, SETTING, AND PARTICIPANTS Our approach was a retrospective cohort study using electronic health record data for patients 50–65 years old with no personal history of CRC or colorectal adenomas with an incident CRC screening colonoscopy from 2001 to 2010 within a multispecialty physician group practice. MAIN OUTCOME MEASURES We measured time to next screening or surveillance colonoscopy and predictors of overuse (exam performed more than one year earlier than guideline recommended intervals) of colonoscopies. KEY RESULTS We identified 1,429 adults who had an incident colonoscopy between 2001 and 2010, and they underwent an additional 871 screening or surveillance colonoscopies during a median follow-up of 6 years. Most follow-up screening colonoscopies (88 %) and many surveillance colonoscopies (49 %) repeated during the study represented overuse. Time to next colonoscopy after incident screening varied by exam findings (no polyp: median 6.9 years, interquartile range [IQR]: 5.1–10.0; hyperplastic polyp: 5.7 years, IQR: 4.9–9.7; low-risk adenoma: 5.1 years, IQR: 3.3–6.3; high-risk adenoma: 2.9 years, IQR: 2.0–3.4, p  < 0.001). In logistic regression models of colonoscopy overuse, an endoscopist recommendation for early follow-up was strongly associated with overuse of screening colonoscopy (OR 6.27, 95 % CI: 3.15–12.50) and surveillance colonoscopy (OR 13.47, 95 % CI 6.61-27.46). In a multilevel logistic regression model, variation in the overuse of screening colonoscopy was significantly associated with the endoscopist performing the previous exam. CONCLUSIONS Overuse of screening and surveillance exams are common and should be monitored by healthcare systems. Variations in endoscopist recommendations represent targets for interventions to reduce overuse.
Suicide prediction models: a critical review of recent research with recommendations for the way forward
Suicide is a leading cause of death. A substantial proportion of the people who die by suicide come into contact with the health care system in the year before their death. This observation has resulted in the development of numerous suicide prediction tools to help target patients for preventive interventions. However, low sensitivity and low positive predictive value have led critics to argue that these tools have no clinical value. We review these tools and critiques here. We conclude that existing tools are suboptimal and that improvements, if they can be made, will require developers to work with more comprehensive predictor sets, staged screening designs, and advanced statistical analysis methods. We also conclude that although existing suicide prediction tools currently have little clinical value, and in some cases might do more harm than good, an even-handed assessment of the potential value of refined tools of this sort cannot currently be made because such an assessment would depend on evidence that currently does not exist about the effectiveness of preventive interventions. We argue that the only way to resolve this uncertainty is to link future efforts to develop or evaluate suicide prediction tools with concrete questions about specific clinical decisions aimed at reducing suicides and to evaluate the clinical value of these tools in terms of net benefit rather than sensitivity or positive predictive value. We also argue for a focus on the development of individualized treatment rules to help select the right suicide-focused treatments for the right patients at the right times. Challenges will exist in doing this because of the rarity of suicide even among patients considered high-risk, but we offer practical suggestions for how these challenges can be addressed.
Do elections matter for private-sector healthcare management in Brazil? An analysis of municipal health policy
Background This study analyzed several political determinants of increased private-sector management in Brazilian health care. In Brazil, the poor depend almost exclusively on the public Unified Health System (the SUS), which remains severely underfunded. Given the overhead costs associated with privately contracted health services, increased private management is one driver of higher expenditures in the system. Although left parties campaign most vocally in support of greater public control of the SUS, the extent to which their stated positions translate into health care policy remains untested. Methods Drawing on multiple publicly available data sources, we used linear regression to analyze how political party-in-power and existing private sector health care contracting affect the share of privately managed health care services and outsourcing in municipalities. Data from two election periods—2004 to 2008 and 2008 to 2012—were analyzed. Results Our findings showed that although private sector contracting varies greatly across municipalities, this variation is not systematically associated with political party in power. This suggests that electoral politics plays a relatively minor role in municipal-level health care administration. Existing levels of private sector management appear to have a greater effect on the public-private makeup of the Brazilian healthcare system, suggesting a strong role of path dependence in the evolution of Brazilian health care delivery. Conclusion Despite campaign rhetoric asserting distinct positions on privatization in the SUS, factors other than political party in power have a greater effect on private-sector health system management at the municipal-level in Brazil. Given the limited effect of elections on this issue, strengthening participatory bodies such as municipal health councils may better enfranchise citizens in the fundamental debate over public and private roles in the health care sector.