Antiphospholipid antibody syndrome (APS) is an uncommon autoimmune disease in which venous and arterial thrombosis frequently occur [1,2]. Retrospective studies have reported that only high-intensity oral anticoagulation [to achieve an international normalized ratio (INR) above 3.0] was effective in preventing thrombotic recurrences [3–5]. However, concerns were raised about the hemorrhagic risk of such intensive anticoagulation treatments [6,7]. A recent randomized clinical trial comparing high vs. moderate intensities of warfarin failed to show a superiority of the more intense regimen for the secondary thromboprophylaxis in APS patients . As it is often the case for rare diseases with severe prognosis, the small size of the study population and the limited number of events on which the negative findings are based do confirm the difficulty of providing univocal answers for this type of clinical conditions.
A closely comparable and totally unrelated protocol – Warfarin in the AntiPhospholipid Syndrome (WAPS) trial – running concurrently in Europe had similar difficulties in enroling a high enough number of patients to provide reliable estimates on the efficacy and safety of high- vs. standard-intensity oral anticoagulation. The results of the WAPS trial are reported here, and their chronological coincidence with those of Crowther et al.  provides a unique opportunity to verify, with a test of consistency, the reliability of the statistically weak power of both studies.