Rationale and design of the self-management of anticoagulation in patients with non-valvular atrial fibrillation (SMAAF) study [Hintergrund und prufplan der studie zum selbstmanagement der antikoagulation bei patienten mit nichtvalvularem vorhofflimmern (SMAAF- studie)]

The objective of this open, randomized, multicenter study is to investigate the benefits and economic efficiency of self-management of oral anticoagulation in patients with atrial fibrillation (SMAAF study) in comparison with a group of patients given conventional care by a general practitioner or specialist. Two thousand patients suitable for self- management will be assigned at random to either the self-management group or the control group. The numbers of thromboembolic and hemorrhagic complications requiring treatment during the 2-year follow-up period will be recorded as the primary end point. The secondary endpoint variables will be maintenance of the INR value in the individual target range, INR variance, the course of complications over time, and the cost efficiency of self- management compared with the routine procedures. The last of these parameters will include the diagnostic and/or therapeutic measures carried out, the duration of inpatient hospital treatment, and the social consequences (subsequent rehabilitation treatment, inability to work, forced retirement). The estimate of the required number of patients was based on the assumption that during long-term anticoagulant therapy within the framework of primary and secondary prevention 4 % of patients with chronic non-valvular atrial fibrillation would have severe thromboembolic of hemorrhagic complications each year. Since this rate can be halved by self-management, a one-tailed χ2-test of 80 % power and a 5 % significance threshold would require n = 997 patients per group. The results of the SMAAF study will establish the socioeconomic benefits of self-management in patients with non-valvular atrial fibrillation.