Objective: To determine the frequency and causes for discontinuing treatment with tenofovir and analyse possible predictive factors for changing this therapy in pretreated HIV patients.
Method: A multi-centre, observational and retrospective study of all HIV patients undergoing treatment with tenofovir between July 2002 and December 2005. Data were obtained from databases for outpatients attending the three pharmacy departments participating in the study, and by reviewing clinical histories. The main sociodemographic, clinical and analytical variables at the start of treatment with tenofovir were collected. The causes for discontinuing treatment were classified as follows: adverse effects, virological failure, death and "other causes". A survival analysis was performed using the Kaplan-Meier method to analyse the possible predictive factors for discontinuing treatment.
Results: A total of 733 patients were included in the study and the median treatment period was 34.7 months. A total of 23.8% of patients discontinued treatment for the following reasons: adverse effects (43.2%), death (17.7%), virological failure (14.8%) and "other causes" (24.4%). There were 99 cases of lost to follow-up. In the survival analysis an association was found between normal serum creatinine values (p = 0.0042) at the start of treatment and the statistically significant probability of discontinuing treatment.
Conclusions: Almost a quarter of the patients discontinued treatment with tenofovir during the study. The main cause for this was adverse effects. No association was found between any abnormal basal analytical parameter and a greater probability of discontinuing treatment.