Anemia, hypoalbuminemia, and renal impairment as predictors of bleeding complications in patients receiving anticoagulation therapy for nonvalvular atrial fibrillation: a secondary analysis

Abstract

Objective: The aim of this analysis was to evaluate the roles of anemia, hypoalbuminemia, and renal impairment as independent predictors of bleeding in patients with nonvalvular atrial fibrillation (NVAF) receiving anticoagulation therapy with warfarin.

Methods: This was a previously published prospective, observational study conducted between November 1999 and July 2001. Patients with NVAF newly started on warfarin and referred to an anticoagulation clinic at a large university hospital (Northern General Hospital, Sheffield, United Kingdom), either at the time of hospital discharge or by their general practitioner, were eligible. Patients were divided into 2 groups: those aged <75 years; and those aged > or =75 years. Patients were seen at the clinic for an initial visit, and baseline information, including age, sex, employment status, medical history, and medication list, was obtained. Patients were also interviewed regarding episodes of bleeding (classified as minor bleeding events or major bleeding events) at the initial patient visit and by telephone every 4 to 6 weeks thereafter.

Results: A total of 402 patients (mean [SD] age, 72.3 [10.3] years [range, 34-94 years]; 224 men [55.7%], 178 women [44.3%]) were included. Follow-up was complete for all patients (mean follow-up, 19.0 [8.1] months [range, 1.0-31.0 months]). A total of 107 minor and 11 major bleeding events were reported. Hypoalbuminemia was a significant predictor of all bleeding in patients aged <75 years (adjusted odds ratio [AOR] = 2.60; 95% CI, 1.26-5.33; P = 0.01), while renal impairment was a significant predictor in patients aged > or = 75 years (AOR = 2.65; 95% CI, 1.71-6.49; P = 0.01). After stratification by bleeding type, renal impairment was a significant predictor of major bleeding in patients aged > or = 75 years (AOR = 2.93; 95% CI, 1.03-9.58; P = 0.001). Anemia was not associated with bleeding.

Conclusion: Hypoalbuminemia and renal impairment were identified as patient-related predictive factors for bleeding, whereas anemia did not appear to increase this risk.