Antiretroviral Therapy Initiating Regimens and Discontinuation Patterns-Medunsa National Pharmacovigilance Centre Cohort, South Africa, 2004 -2011

Background: An estimated 1.6 million HIV infected patients are on antiretroviral therapy (ART) in South Africa. ART is life-long and reduces morbidity and mortality in HIV-infected patients; however discontinuation of the treatment leads to inferior clinical outcomes and increases the risk of drug resistance. This study determined ART initiating and discontinuation patterns in a cohort of patients in four sentinel sites in South Africa.

Methods: Retrospective analysis of ART surveillance data collected by the Medunsa National Pharmacovigilance Centre. ART initiation was defined as putting a patient on an ART drug regimen, and discontinuation was defined as stopping of all ART drugs being taken by a patient at any time for a specified or unspecified reason.

Results: A total of 2979 patient data was analysed. Most, 2030 (68.1%) were females. Mean age at ART initiation was 38.1 years (standard deviation: 37.8; 38.5). ART was discontinued at least once in 105/2979 (3.5%) patients. The highest proportion (25%) of ART discontinuations were on patients initiated on non-standard drug regimens. None of the patients initiated on second line regimens discontinued ART. Reasons cited for ART discontinuation included drug-related toxicity (24%), poor adherence (23%), non-adherence 11%, treatment failure (10%) and loss to follow-up (10%). Initiating patients on non-standard drug regimens (Relative risk (RR) =7.42; 95% confidence interval (CI):2.73-20.14), and initiating treatment on patients below 26years of age (RR=7.9 CI: 1.76-4.78) were associated with ART discontinuation.

Conclusion: Young age at ART initiation and use of non-standard drug regimens are predictors of ART discontinuation. Clinicians should be encouraged to initiate patients on standard first line ART regimens. Adherence counselling is crucial especially in younger patients on ART. Predictors of non-adherence to ART should be investigated.