Factors affecting viral load suppression in people living with HIV in Nigeria: cross-sectional analysis from 2001 to 2021

Background Human immunodeficiency virus (HIV) is untransmissible when the viral load (VL) is undetectable, underscoring the importance of achieving VL suppression for HIV epidemic control. It is estimated that 78% of people living with HIV (PLHIV) on antiretroviral therapy (ART) in Nigeria are virally suppressed. The need to improve VL suppression rates raises questions about the factors associated with an unsuppressed VL, which this study explored using a large cross-sectional database of clients who received ART over a period of 20 years. Methods Data from 517,012 clients with a documented VL were analyzed using univariate and adjusted multivariate logistic regression. The independent variables investigated were sex, age group, facility type, time on ART until last VL test, multi-month dispensing (MMD), and geopolitical zone. To verify model improvement by variable, we performed backward elimination for the logistic regression model. Results Sixty-six percent of the study population were females. The largest age groups were 35–44 and 25–34, accounting for 32% and 31%, respectively. The greatest adjusted odds for an unsuppressed VL were associated with shorter duration MMD prescriptions of 1–2 months (adjusted odds ratio [AOR]=14.05) and 3 months (AOR=3.13). Males had 8% greater odds (AOR=1.08) of being unsuppressed. The age groups below the 45–59 age group (AOR=0.84) had higher odds of having an unsuppressed VL, with the highest odds in the 0–14 age group (AOR=1.87). Clients enrolled at tertiary and secondary level facilities had the greatest odds of having an unsuppressed VL. A shorter time on ART until the last VL (1–3 years [AOR=1.14]) was associated with a higher risk of an unsuppressed VL. Clients in the North-Central (AOR=1.83) and North-East (AOR=1.49) zones had the greatest odds of viral non-suppression. Conclusions Enabling the provision of 3+ months of MMD to PLHIV and targeting younger age groups, tertiary and secondary health facilities, small and medium facilities, and the North-Central and North-East zones for interventions could lead to improvements in VL suppression in Nigeria. The independent factors associated with an unsuppressed VL can guide improvements in ART program development and VL suppression of PLHIV in Nigeria.