Trends in CD4 and viral load testing 2005 to 2018: Multi-cohort study of people living with HIV in Southern Africa

Introduction: WHO recommends a CD4 cell count before starting antiretroviral therapy (ART) to detect advanced HIV disease, and routine viral load (VL) testing following ART initiation to detect treatment failure. Donor support for CD4 testing has declined to prioritize access to VL monitoring. We examined trends in CD4 and VL testing among adults (≥15 years of age) starting ART in Southern Africa. Methods: We analysed data from 14 HIV treatment programs with over 300 clinics in Lesotho, Malawi, Mozambique, South Africa, Zambia and Zimbabwe in years 2005-2018. We examined the frequency of CD4 and VL testing, the percentage of adults with CD4 or VL tests, and among those having a test, the percentage starting ART with advanced HIV disease (CD4 count 1000 HIV-RNA copies/ml) after ART initiation. We used mixed effect logistic regression to assess time trends adjusted for age and sex. Results: Among 502,456 adults, the percentage with CD4 testing at ART initiation decreased from a high of 78.1% in 2008 to a low of 38.0% in 2017. The percentage starting with advanced HIV disease declined from 83.3% in 2005 to 23.5% in 2018. VL testing after starting ART varied; 61.0% of adults in South Africa and 10.7% in Malawi were tested but fewer than 2% were tested in the other four countries. The probability of having a CD4 cell count at ART start declined by 14% each year (odds ratio [OR] 0.86; 95% CI 0.86-0.86); the probability of advanced HIV disease declined by 20% per year (OR 0.80; 95% CI 0.80-0.81). The increase in VL testing after ART start was only modest (OR 1.06; 95% CI 1.05-1.06) and there was no evidence of a decrease in unsuppressed VL over time (OR 1.00; 95% CI 0.99-1.01). Conclusions: CD4 cell counting declined over time, including testing at the start of ART, despite the fact that many patients still initiated ART with advanced HIV disease. Without CD4 testing and expanded VL testing many patients with advanced HIV disease and treatment failure may go undetected, threatening the effectiveness of ART in sub-Saharan Africa.