CD4 and Opportunistic infection: The multivariable Cox proportional hazards regression analysis showed that older age clients, male ART clients, bedridden clients, ambulatory clients, TB co-infected clients at ART initiation, clients who develop TB co-infection after ART initiation, type of drug regimen used, drug adherence, clients with low CD4 count, and clients who had developed other opportunistic infection had a statistically significant association with treatment failure among ART clients.