An Evaluation of Statin Use Among Patients with Type 2 Diabetes at High Risk of Cardiovascular Events Across Multiple Health Care Systems

BACKGROUND: Patients with more than one chronic condition often receive care from several providers and facilities, which may lead to fragmentation of care. Poor care coordination in dual health care system use has been associated with increased emergency department visits, hospitalizations, and costs. OBJECTIVE: Dual health care system use is increasing among veterans, and we sought to evaluate the effect of dual health care system use on statin treatment in veterans with type 2 diabetes at high risk of cardiovascular events, using varying degrees of Centers for Medicare & Medicaid Services (CMS) services. METHODS: This was a 10-year retrospective longitudinal cohort study of national clinical and administrative data that included 689,138 veterans with type 2 diabetes who were aged 65 years or older on January 1, 2006. Patients were followed from January 1, 2007, until December 31, 2016. Administrative and clinical data from the Veterans Health Administration’s (VHA) Corporate Data Warehouse were merged with CMS inpatient, outpatient, and pharmacy data. Statin use was defined as any therapy and subcategorized as high versus low or moderate intensity per the American College of Cardiology/American Heart Association guidelines. Marginal generalized estimating equation-type models for longitudinal data were used to model the association between dual health care utilization status (< 50%, 50%-80%, and > 80% VHA utilization, with the first group serving as the reference group) and statin use after adjusting for measured covariates. RESULTS: The mean ages at baseline for each group were similar and ranged between 75.4 and 76.9 years. For the outcome of any statin use, the group with < 50% VHA utilization was significantly less likely to receive statin therapy compared with the group with > 80% VHA utilization (OR = 0.26, 95% CI = 0.26-0.26), while the group with 50%-80% VHA utilization was slightly more likely (OR = 1.05, 95% CI = 1.04-1.07). Similarly, for the high-intensity versus low-/moderate-intensity or no statins outcome, the group with < 50% VHA utilization was significantly less likely to receive a high-intensity statin compared with the group with > 80% VHA utilization (OR = 0.56, 95% CI = 0.55-0.57), while the group with 50%-80% VHA utilization was only slightly less likely (OR = 0.95, 95% CI =0.94-0.96). CONCLUSIONS: Among veterans with diabetes at high risk of cardiovascular events, dual health care system utilization status appeared to affect statin use. We observed lower odds for any statin use and high-intensity statin therapy among the cohort with the lowest degree of VHA utilization (i.e., < 50%). Interventions to increase statin use among veterans at high risk of cardiovascular events with lower degrees of VHA utilization should be explored.