Extent and reasons for substituting and switching highly active antiretroviral therapy at the Katutura Intermediate Hospital in Windhoek, Namibia
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Background: Namibia is one of the Southern African countries hardest hit by the HIV epidemic, with an estimated one out of every five people infected (MoHSS, 2004). Approximately 80,000 of the infected population currently require antiretroviral treatment (ART). In order to prevent the progression of the HIV infection to AIDS, patients are required to take antiretroviral medicines lifelong. This lifelong use exposes patients to toxicities of these medicines and the only available options of managing the toxicities of ARVs are to treat the toxicity or substitute or switch the offending medicines. Aim: The current study aimed to describe the extent and reasons for substituting and switching HAART at the Katutura Intermediate Hospital in Windhoek, Namibia. Methodology: A descriptive retrospective case series study, in which medical records were reviewed to determine the extent and reasons for substituting and switching HAART was conducted. Random sampling was used to draw a sample of 500 from 3477 adult HAART patients who commenced treatment between 1 January 2002 and 31 December 2006. A prepiloted data collection tool was used to collect the data. The following information was collected: baseline CD4 count, weight, initial ARVs, first and second ARV substitutions, ART switch and the reasons for substituting ARVs or switching ART during the indicated period. Epi Info version 6 was used to analyse frequencies, means and medians of all important variables in the data set. Results: The sample was made up of 500 HAART patients; 60% were females. The median age of the sample was 34 years (Inter-quartile range (IQR) 30 – 40) and the median CD4 cell count was 153 cells/mm3 (IQR 96 – 212) at initiation of therapy. The median time on treatment before first substitution was 28 months (IQR 24 – 34), whereas the median time before second substitution was 10 months (IQR 6 – 15) from the time of the first substitution. The median time before switching was 31 months (IQR 24 - 39). A total of 31% of the study subjects underwent a substitution once, whereas 1.8% underwent a second substitution. Only six (1.2%) patients switched to a second line treatment after the modification of the treatment. The most commonly recorded reason for the first substitution was toxicity (19%). As in other studies, stavudine (D4T), nevirapine (NVP) and efavirenz (EFV) were the ARVs associated with most of the recorded toxicities. High viral load (50%) was the most reported reason for switching. In almost half of the substitution cases the reasons for substitution were not stated, and in a third of the switch cases the reasons for switching were not stated. Conclusion: The rate of substitution at 31% was similar to that found in other resource poor settings, however, the rate of switching (1.2%) was much lower than was found in similar settings. The main reason stated for substituting antiretrovirals was “toxicity”.