Does coumarin therapy improve survival in incident dialysis patients?
Coumarin therapy appears safe and does not significantly increase mortality in incident dialysis patients when clearly indicated and closely monitored.
BACKGROUND: The benefit and risk of oral anticoagulation in dialysis patients are debated controversially. METHODS: We prospectively followed 235 dialysis patients of the INVOR Study (Study of Incident Dialysis Patients in Vorarlberg) for up to 7 years and analysed the prevalence and incidence of atrial fibrillation (AF) and the impact of coumarin therapy on survival. Oral anticoagulation was monitored frequently. RESULTS: A total of 748 person-years were recorded with a median follow-up of 2.84 years. Twelve patients (5.1%) had AF at the start of dialysis. During follow-up, 40 patients (17.0%) developed AF, representing an incidence of 5.85 per 100 person-years. AF was positively associated with mortality (P = 0.004). Forty-six (19.6%) of the 235 patients were treated with coumarins. The majority (93.7%) had a clear indication for oral anticoagulation. In 65% of our patients, AF was the indication for coumarins. Patients without coumarins and without AF represented our reference group. The mortality risk of the coumarin-treated patients with AF or an alternative indication for coumarins was slightly lower compared to the reference group hazard ratio (HR) 95% confidence interval (CI): 0.80 (0.28-2.29), P = 0.679 and 0.42 (0.16-1.10), P = 0.078, respectively. No patient under sufficient oral anticoagulation experienced a stroke or a fatal bleeding event. Patients with AF and a contraindication for coumarins had a significantly higher mortality risk compared to the reference group HR (95% CI): 3.90 (2.16-7.04), P < 0.001. CONCLUSIONS: Our data suggest that coumarins might be less harmful than previously anticipated when clearly indicated and closely monitored.
Knöll et al. (Mon,) studied this question.