Comparative incidence of adverse drug reaction during the first and subsequent year of antiretroviral therapy in a Nigerian HIV infected Cohort.

backgroundDespite close to two decades of antiretroviral therapy (ART) in Nigeria, data on late on-onset ART-associated adverse drug reactions (ADRs) are sparse.

objectivesTo describe early and late-onset ADRs and compare their incidence in an outpatient HIV positive Cohort on ART.

methodWe described the incidence of clinical ADRs identified and documented in an outpatient clinic cohort of HIV-positive patients treated between June 2004 and December 2015 at a tertiary health facility in Nigeria. Incidence rates of ADRs during the first and subsequent years of ART were compared.

resultsof the 13,983 patients' data analyzed, 9317 were females (66%), and those in the age bracket of 25 to 45 years made up 78% of the studied population. During 52,411 person-years (py) of ART, 1485 incident ADRs were recorded; Incidence rate (IR) 28.3 (95% confidence interval [CI] 26.9:29.8) ADRs per 1000 person-years (py) of ART. The IR of ADRs was about two times higher in the first year of ART compared to subsequent years of treatment; crude incidence rate ratio (IRR) 1.77 (95% CI 1.59:1.97). Anemia, hypersensitivity reactions, and nervous system disorders had 7, 23, and 5 times higher incidence, respectively, in the first year of therapy, compared to subsequent years.

conclusionThe first year of ART is the period of highest risk of ADRs. Individual and programmatic treatment success in resource-limited settings requires strategies for early identification and management of ADR during the period of greatest risk of ADRs.