the oral anticoagulant therapy ( oat ) , used to prevent thrombosis , is associated with substantial avoidable hospitalization . identify the associations between chronic care management and the quality of oat as suggested by the chronic care model ( ccm ) of wagner . regression analysis with data of 61 thrombosis clinics and inductive analysis with 63 interviews with health care professionals of 23 thrombosis clinics . results show substantial differences between regions in the quality of thrombosis care and the ccm activities . however , the variation in quality of care was not associated with the differences in ccm activities . several preferred ccm activities ( e.g. , multidisciplinary protocol ) as well as the barriers to implement these activities ( e.g. , conflicting interests ) were put forward by the health care professionals . it can be concluded that there is variation in quality of thrombosis care between regions .