BACKGROUND : People infected with HIV are prone to
venous thrombosis. Treatment of thrombosis is
primarily with warfarin. No studies have addressed the
effects of HIV infection on warfarin dose. The aims of
this study were to determine whether the therapeutic
dose of warfarin and induction time to therapeutic
dose in HIV-infected patients differ from that in HIV-uninfected
METHODS : A prospective and retrospective descriptive
study of induction time to therapeutic warfarin dose, as
well as of ambulant therapeutic warfarin dose, was
performed. HIV-infected and HIV-uninfected patients
being treated after deep venous thrombosis with or
without pulmonary embolism were compared. Sex and
use of antiretroviral drugs (ARVs) were also compared
in the groups.
RESULTS : 234 patients were entered into the study.
Induction time to therapeutic warfarin dose did not
differ between the 2 groups. The mean therapeutic
dose of warfarin was higher in the HIV-infected than
the HIV-uninfected group: 6.06 vs 5.72 mg/day, but
this was not statistically significant ( p=0.29). There
was no difference in therapeutic warfarin dose between
ARV-naïve groups—HIV-uninfected and HIV-infected
patients not on ARVs.
CONCLUSIONS : There appears to be little effect of HIV infection on warfarin dosing. Warfarin therapy should
be administered conventionally in HIV-infected patients.