High-dimensional confounding adjustment using continuous spike and slab priors

In observational studies, estimation of a causal effect of a treatment on an outcome relies on proper adjustment for confounding. If the number of the potential confounders ( p ) is larger than the number of observations ( n ), then direct control for all potential confounders is infeasible. Existing approaches for dimension reduction and penalization are generally aimed at predicting the outcome, and are less suited for estimation of…

Propensity scores with misclassified treatment assignment: a likelihood-based adjustment

Oxford University Press | April 17, 2017 Propensity score methods are widely used in comparative effectiveness research using claims data. In this context, the inaccuracy of procedural or billing codes in claims data frequently misclassifies patients into treatment groups, that is, the treatment assignment ($T$) is often measured with error. In the context of a validation data where treatment assignment is accurate, we show that misclassification of treatment assignment can impact…

Best Practices for Gauging Evidence of Causality in Air Pollution Epidemiology

American Journal of Epidemiology | September 6, 2017 The contentious political climate surrounding air pollution regulations has brought some researchers and policy makers to argue that evidence of causality is necessary for more stringent regulations. Recently, an increasing number of air pollution studies purport the use of “causal analysis,” generating the impression that studies not explicitly labeled as such are merely “associational” and therefore less rigorous. Using three prominent air…

Air Pollution and Mortality in the Medicare Population

New England Journal of Medicine | June 29, 2017 Studies have shown that long-term exposure to air pollution increases mortality. However, evidence is limited for air-pollution levels below the most recent National Ambient Air Quality Standards. Previous studies involved predominantly urban populations and did not have the statistical power to estimate the health effects in underrepresented groups. Read more here

Air Pollution Still Kills

Editorial, New England Journal of Medicine | June 29, 2017 In late October 1948, a dense smog descended over the town of Donora, Pennsylvania. The town was home to a zinc plant and a steel mill, both run by the United States Steel Corporation. Susan Gnora, a 62-year-old resident of Donora, started to gasp and cough as the smog descended. She died the next day. Dr. William Rongaus, a physician…

Drought linked with human health risks in US analysis, Berman et al.

In a retrospective study of health claims for 618 U.S. counties over 14 years, published in The Lancet, researchers found that severe drought conditions increased the risk of mortality among adults 65 or over. They also found that individuals in places where droughts were rare, such as counties in Minnesota, showed a larger risk of mortality and cardiovascular disease compared with counties where drought is more common. Read more here

Cardiovascular disease-related hospital admissions jump on second day after major snowfall, Bobb et al.

According to a new study by researchers from Harvard T.H. Chan School of Public Health, hospital admissions for cardiovascular diseases decline on days with major snowfalls compared to days with no snowfall, but they jump by 23% two days later. Lead author Jennifer Bobb of the Group Health Research Institute in Seattle, who worked on the study as a postdoctoral researcher in the Department of Biostatistics at Harvard Chan School,…

Video Simulations of PM2.5 Levels in Europe and the United States, Choirat

Evolution of PM2.5 levels in Europe and the United States The following videos depict the evolution of PM2.5 levels from 1998-2015 in Europe and the United States. The same color scales are used for both videos. As shown, there are drastic improvements in air quality for the whole US, while air quality in Europe does not show much improvement and some areas, including Milan, worsen. Video Author: Christine Choirat Data Sources:…

Readmission Rates After Passage of the Hospital Readmissions Reduction Program: A Pre–Post Analysis, Wasfy et al.

Passage of the Patient Protection and Affordable Care Act (ACA) in March 2010 created the Medicare Hospital Readmissions Reduction Program (HRRP), which introduced the prospect of financially penalizing hospitals based on their previous performance. This program represents one of several efforts to encourage provider organizations to enhance safety and value. Medicare has reported lower readmission rates since passage of the law, but whether the lowest-performing hospitals might experience less rapid improvement…

Giving a Voice to Future Leaders at Harvard’s Women’s Weekend

When asked to address the powerful group of women who attended Harvard’s inaugural university-wide Women’s Weekend (11/5-11/6), Dr. Francesca Dominici chose to take a different approach, placing the microphone in the hands of a panel of young female experts. Dominici, who advocates for institutional and cultural changes by starting with the subtle inequities that affect students, questioned her experts, a group of articulate 5th grade and high school students, about…