An electronic health record based model predicts statin adherence, LDL cholesterol, and cardiovascular disease in the United States Military Health System.

HMG-CoA reductase inhibitors (or "statins") are important and commonly used medications to lower cholesterol and prevent cardiovascular disease. Nearly half of patients stop taking statin medications one year after they are prescribed leading to higher cholesterol, increased cardiovascular risk, and costs due to excess hospitalizations. Identifying which patients are at highest risk for not adhering to long-term statin therapy is an important step towards individualizing interventions to improve adherence. Electronic health records (EHR) are an increasingly common source of data that are challenging to analyze but have potential for generating more accurate predictions of disease risk. The aim of this study was to build an EHR based model for statin adherence and link this model to biologic and clinical outcomes in patients receiving statin therapy. We gathered EHR data from the Military Health System which maintains administrative data for active duty, retirees, and dependents of the United States armed forces military that receive health care benefits. Data were gathered from patients prescribed their first statin prescription in 2005 and 2006. Baseline billing, laboratory, and pharmacy claims data were collected from the two years leading up to the first statin prescription and summarized using non-negative matrix factorization. Follow up statin prescription refill data was used to define the adherence outcome (> 80 percent days covered). The subsequent factors to emerge from this model were then used to build cross-validated, predictive models of 1) overall disease risk using coalescent regression and 2) statin adherence (using random forest regression). The predicted statin adherence for each patient was subsequently used to correlate with cholesterol lowering and hospitalizations for cardiovascular disease during the 5 year follow up period using Cox regression. The analytical dataset included 138 731 individuals and 1840 potential baseline predictors that were reduced to 30 independent EHR "factors". A random forest predictive model taking patient, statin prescription, predicted disease risk, and the EHR factors as potential inputs produced a cross-validated c-statistic of 0.736 for classifying statin non-adherence. The addition of the first refill to the model increased the c-statistic to 0.81. The predicted statin adherence was independently associated with greater cholesterol lowering (correlation = 0.14, p < 1e-20) and lower hospitalization for myocardial infarction, coronary artery disease, and stroke (hazard ratio = 0.84, p = 1.87E-06). Electronic health records data can be used to build a predictive model of statin adherence that also correlates with statins' cardiovascular benefits.

Usefulness of tobacco check boxes on death certificates: Texas, 1987-1998.

OBJECTIVES: We compared reports of deaths in which tobacco use was a contributing factor ("tobacco-associated deaths") before and after the addition to death certificates in Texas of a check-box question asking whether tobacco use contributed to an individual's death. METHODS: We examined Texas vital statistics files from 1987 to 1998. We calculated differences in percentages of reported tobacco-associated deaths (and 95% confidence intervals [CIs]) for the periods 1987 to 1992, before the addition of the check-box question, and 1993 to 1998, after the addition of the check-box. RESULTS: Reports of tobacco-associated deaths were significantly less frequent before addition of the check-box question (0.7%; 95% CI = 0.4%, 1.0%) than after addition of the question (13.9%; 95% CI = 13.0%, 14.7%). From 1993 to 1998, percentages of tobacco-associated deaths reported on the check-box question increased steadily. CONCLUSIONS: The addition of a tobacco-associated-death check box on Texas death certificates significantly increased reporting of tobacco use contributions to mortality.