Clinical outcomes and treatment patterns among Medicare patients with nonvalvular atrial fibrillation (NVAF) and chronic kidney disease

BACKGROUND: Patients with nonvalvular atrial fibrillation (NVAF) and chronic kidney disease (CKD) have increased risk of adverse outcomes. This study evaluated treatment with oral anticoagulants and outcomes in elderly NVAF patients with CKD. METHODS: Retrospective observational cohort study of US Medicare fee-for-service patients aged ≥66 years with comorbid CKD (advanced: Stage 4 and higher; less advanced: Stages 1-3) and a new NVAF diagnoses from 2011-2013. All-cause mortality, stroke, major bleeding, and myocardial infarction rates were estimated for 1 year post-NVAF diagnosis. Associations between CKD stage and outcomes were evaluated with multivariate-adjusted Cox regression. We assessed oral anticoagulant (OAC) receipt within 90 days post-NVAF diagnosis and associations between OAC receipt and outcomes. RESULTS: There were 198,380 eligible patients (79,681 with advanced CKD). After adjustment for age, gender, and comorbidities, advanced CKD was associated with increased mortality (Stage 5 HR 1.47; 95% CI 1.42-1.52), MI (HR 1.48; 95% CI 1.33-1.64), stroke (HR 1.23; 95% CI 1.11-1.37) and major bleed (HR 1.44; 95% CI 1.36-1.53) risks. Among Medicare Part D enrollees who survived ≥90 days post-NVAF diagnosis, 65-71% received no OACs in the first 90 days. Those receiving warfarin (HR 0.73; 95% CI 0.71-0.75) or DOACs (HR 0.52; 95% CI 0.49-0.56) within the first 90 days had reduced mortality in the period 90 days to 1 year following NVAF diagnosis compared to those without. CONCLUSION: Elderly NVAF patients with advanced CKD (Stage 4 or higher) had higher mortality risks and serious clinical outcomes than those with less advanced CKD (Stage 1-3). OAC use was low across all CKD stages, but was associated with a lower mortality risk than no OAC use in the first year post-NVAF diagnosis.