Cotrimoxazole use and immune system recovery among newly initiating HIV-infected patients in an urban outpatient HIV clinic in Johannesburg, South Africa

Abstract

Background: Previous research has shown that cotrimoxazole (CTX) use reduces mortality for patients initiating antiretroviral therapy (ART). We investigated whether CTX also accelerates immune recovery and reduces loss to follow-up (LTF) at an outpatient HIV clinic in South Africa. Methodology: We included all adult (≥18) ART-naïve patients initiating standard first-line treatment between April 2004 and March 2012 at Themba Lethu Clinic in Johannesburg. Patients were followed from ART initiation until death, transfer, LTF (≥3 months late for a scheduled visit with no subsequent visit), or close of the dataset (July 31, 2013). As per the South African National ART Guidelines, patients were eligible to receive CTX if their CD4 count was <200 cells/mm3 or they had a WHO stage II, III, or IV condition. The exposure was defined as being on CTX at the time of ART initiation or starting within 3 months of initiation. Immune system recovery was defined as achieving a CD4 count >200 cells/mm3. A modified Poisson regression model was used to examine associations between CTX use and LTF by 12 months. Results: 15423 patients initiated ART between April 2004 and March 2012, were eligible to receive CTX, and were included in the analysis. 60.2% of patients were female, the median (IQR) age was 36.8 (31.5-43.3) years, and the median (IQR) baseline CD4 count was 86 (32-152) cells/mm3. Patients who did not receive CTX (14.7%) were similar to patients who did receive CTX although they did have a slightly higher, though not clinically significant, median baseline CD4 count (98 vs 85). Patients with a baseline CD4 count from 25-49 cells/mm3 who did not receive CTX took a median of 388 days to achieve immune system recovery while patients who received CTX recovered in a median of 358 days. Likewise, patients in the 50-99 cells/mm3 category who did not receive CTX reached immune recovery in 319 days while those who received CTX recovered their immune system in a median of 264 days. Upon completion of 12 months of follow up, patients who did not receive CTX were more likely to be LTF (17.1% vs 11.0%) than patients who received CTX. However, in a model adjusted for baseline clinical characteristics, only a slight increased risk for loss remained (aRR: 1.12; 95% CI: 0.95, 1.31). Conclusions: Lack of provision of CTX to newly initiating HIV-infected patients results in delayed immune recovery up to 8 weeks. Further research is needed to determine the impacts of such delays in immune recovery on treatment outcomes.

Conference: IWHOD 2014, Sitges, Spain