BACKGROUND: Adherence is one of the main predictors of antiretroviral treatment success. A governmental initiative was launched in 1998 for HIV-infected patients in Senegal to provide access to highly active antiretroviral therapy (HAART).
METHODS: Between August 1998 and April 2002, 404 adult patients were enrolled. Adherence measurements, defined as pills taken/pills prescribed, were assessed between November 1999 and April 2009 using a pill count along with a questionnaire for 330 patients. Predictors of adherence were explored through a random-intercept Tobit model and a latent class analysis (LCA) was performed to identify adherence trajectories. We also carried out a survival analysis taking into account gender and latent adherence classes.
RESULTS: Median treatment duration was 91 months [IQR 84-101]. On average, adherence declined by 7% every year, was 30% lower for patients taking indinavir and 12% higher for those receiving cotrimoxazole prophylaxis. Based on the predicted probability of having an adherence ≥ 95%, LCA revealed three adherence behaviours and a better adherence for women. A quarter of patients had a high adherence trajectory over time and half had an intermediate one. Male gender and low adherence behaviour over time were independently associated with a higher mortality rate.
CONCLUSIONS: This study shows that an overall good adherence can be obtained in the long-term in Senegal. LCA suggests a better adherence for women and points out a large sub-sample of patients with intermediate level of adherence behaviour at risk for developing resistance to antiretroviral drugs. This study warrants further research into gender issues.