Revisiting long-term adherence to highly active antiretroviral therapy in Senegal using latent class analysis.

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. 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 performed a survival analysis taking into account gender and latent adherence classes. RESULTS: Median treatment duration was 91 months (interquartile range, 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 3 adherence behaviors 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 behavior 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 subsample of patients with intermediate level of adherence behavior who are at risk for developing resistance to antiretroviral drugs. This study warrants further research into gender issues.

A 84-month follow up of adherence to HAART in a cohort of adult Senegalese patients.

OBJECTIVES: To assess long-term adherence of the first HIV-1 patients receiving highly active antiretroviral therapy (HAART) in Senegal, and to identify the main determinants of adherence. METHODS: The first 180 patients enrolled in the Senegalese HAART initiative between August 1998 and April 2001 followed up for at least 30 days were eligible. Adherence was assessed monthly at each drug dispensation between November 1999 and November 2006 by a pharmacist using a pill count completed by a questionnaire. Adherence was expressed as the proportion of tablets taken to prescribed tablets. An adherence of 95% was considered to be good. A random-intercept logit model was fitted to identify the main determinants of adherence. RESULTS: Adherence data were available for 158 of 167 eligible patients. Twenty-nine patients died during the study period and 10 were lost to follow-up. Median treatment duration was 78 months, accruing to 6657 person-months of observation. Overall, mean adherence reached 91% [median: 100%, interquartile range (IQR) 96-100%] and adherence exceeded 95% in 78% [95% CI 77-79%] of observations. After 4 years of treatment mean adherence stabilized around 90% and adherence > or =95% stabilized around 70%. Treatment duration and protease inhibitor (PI)-based regimen (indinavir) had a negative effect on adherence, but adherence tended to improve with time for patients receiving a PI. Patient-level variance was highly significant and accounted for a third of total variance. CONCLUSIONS: This work demonstrates that good long-term adherence can be achieved in the sub-Saharan context given close monitoring and adherence support measures, confirms the worse adherence for indinavir and underlines the importance of patient heterogeneity.