Effect of injectable contraceptive use on response to antiretroviral therapy among women in Rakai, Uganda.

BACKGROUND: There is limited evidence on the effect of injectable contraception on response to antiretroviral therapy (ART).
DESIGN: Using modified Poisson regression, we assessed data from 418 female Ugandan ART initiators to examine the effect of injectable contraceptive use on a composite virologic failure outcome (defined as failure to achieve virologic suppression, switch to second line therapy, or death within 12 months of ART initiation) and also assessed ART adherence.
RESULTS: About 12% of women reported using injectable contraceptives at ART initiation, and their composite virologic failure rates 12 months later were similar to women not using injectable contraceptives at ART initiation (11% vs. 12%, p=0.99). Multivariable Poisson regression suggested no significant differences in virologic failure by injectable contraceptive use at baseline (prevalence risk ratio: 0.85, p=0.71), but power was limited. Adherence to ART increased with time since ART initiation, and did not appear to differ between injectable contraceptive users and non-users.
CONCLUSIONS: Consistent with current World Health Organization guidelines, our results suggest no deleterious effect of injectable contraceptive use on response to ART, but power was limited, injectable contraceptive use patterns over time were inconsistent and additional evidence is needed.