F5 and antiphospholipid syndrome: Compared with the presence of a heterozygous FVL mutation, antiphospholipid antibody syndrome (odds ratio (OR), 8.26; 95% CI, 5.40–12.62), AT deficiency (OR, 5.15; 95% CI, 2.84–9.34) and homozygous FVL mutation (OR, 3.93; 95% CI, 2.10–7.34) influenced further treatment the most (Table 4).