Patterns and Predictors of First-Line Antiretroviral Therapy Modification in HIV-1-Infected Adults in a Large Urban Outpatient Cohort in Nigeria

Objective: We described the magnitude, type, and factors associated with first-line antiretroviral therapy (ART) modification in HIV-1-infected adults on ART in Jos, Nigeria. Method: Data on 6309 patients initiated on first-line ART between January 2004 and December 2006 were analyzed retrospectively. Factors predictive of modification to initial ART were assessed by chi-square and multivariable logistic regression analysis. Results: Overall, 5212 (83%) included patients incurred a modification (73.3% drug substitution and 9.7% drug switch) to their initial first-line ARV regimen during a median (interquartile range) follow-up period of 7 (3-8) years. Drug substitutions of zidovudine (ZDV) were less likely than of tenofovir (TDF; adjusted odd ratio [AOR] 0.6; 95% confidence interval [CI]: 0.51-0.71), and Drug substitutions of efavirenz (EFV) were more likely than of nevirapine (NVP)- containing (AOR 1.82; 95% CI: 1.42-2.33) regimens. Predictors of switch to second-line regimen include older age (AOR 2.05; 95% CI: 1.68-2.51), CD4 count ≥100 cells/mm3 (AOR 1.89; 95% CI: 1.49-2.37), EFV compared to NVP (AOR 1.38; 95% CI: 1.02-1.88), and drug toxicity (AOR 1.90; 95% CI: 1.48-2.43). Conclusion: Modification to initial ART was common in this study. Further evaluation of the contribution of guideline changes on regimen modification and treatment outcomes is recommended.