ARE THERE DIFFERENCES IN ORAL ANTICOAGULANT THERAPIES IN HOSPITALIZED PATIENTS WITH ATRIAL FIBRILLATION AND MODERATE VERSUS SEVERE RENAL DYSFUNCTION?

Abstract

The prevalence of atrial fibrillation (AF) increases with age and declining renal function. Oral anticoagulant therapy (OAC) is recommended in these patients, but few studies have examined the effect of varying degrees of renal dysfunction in AF management. We examined medical comorbidities and OAC treatment of hospitalized patients presenting to an academic hospital with AF and renal dysfunction. A retrospective cohort study of all hospitalized patients presenting to St. Michael’s Hospital with ECG-documented AF were identified from January 2010 to December 2014. For patients with more than one visit, only the first visit was abstracted. Patients hospitalized in the intensive care or coronary care units and those who died during admission were excluded. Patient demographics, medical history, and OAC status including warfarin and direct oral anticoagulants (DOACs) were recorded. Estimated glomerular filtration rate (eGFR) was calculated using the simplified Modification of Diet in Renal Disease (MDRD) formula. Renal dysfunction was defined as eGFR<60 mL/min/1.73m2 and separated into three groups: 1) Moderate (eGFR 30-59 mL/min/1.73m2), 2) Severe (eGFR 15-29 mL/min/1.73m2) and 3) Renal failure (eGFR <15 mL/min/1.73m2). Stroke risk was classified according to CHADS2 scoring system. 1,131 inpatients with ECG-documented AF, eGFR<60 mL/min/1.73m2 and CHADS2≥1 were included. The mean age was 78.3±10.2 years and mean creatinine was 178.1±135.2 (82-1,106) μmol/L. At hospital discharge, the mean eGFR was 39.7±14.8; 171 (15.1%) had severe decrease in renal function and 112 (9.9%) had renal failure. Clinical characteristics, by eGFR at hospital discharge are shown in Table 1. In patients with moderate renal dysfunction, 504 (59.4%) received any OAC compared to 119 (42.1%) with severe renal dysfunction or failure (p<0.0001). At hospital discharge, patients with severe renal dysfunction compared to patients with renal failure were more likely to be prescribed warfarin (50.9% vs. 25.9%, p<0.0001) and DOACs (1.8% vs. 0%, p=NS). Among hospitalized patients with renal dysfunction with ECG-documented AF and guideline-indicated for stroke prevention, patients with severe decrease in renal function and renal failure were less likely to be anticoagulated compared to those with moderate renal dysfunction.