Introduction:
An appropriate economic evaluation of post-exposure prophylaxis (PEP) should consider the effectiveness of different regimens prescribed for patients. Studies have not evaluated the comparative effectiveness of different PEP antiretrovirals (ARVs) based on their costs. Therefore, the aim of the present study was to determine the cost-effectiveness of ARVs regimens used for PEP in Nigerian tertiary hospitals.

Material and methods:
This cross-sectional study collated patients’ demographic and clinical data from PEP databases of United States’ President Emergency Plan for AIDS Relief – AIDS Prevention Initiative in Nigeria hospitals. Costs of ARVs were obtained from donors’ price list. Effectiveness was measured as the percentage of human immunodeficiency virus (HIV)-negative patients one-month post-PEP. Average cost-effectiveness ratios (ACERs) were computed as the unit cost of the regimens/HIV infection averted (HIA). Probabilistic sensitivity analysis was conducted using 1,000 iterations using Monte-Carlo simulation.

Results:
Out of 575 patients identified, 198 (34.4%) had non-occupational exposure. Of the 14 regimens, tenofovir (TDF) + lamivudine (3TC) + ritonavir-boosted atazanavir (ATV/r) was prescribed for 230 (40.00%) patients. HIV-negative results were documented in 129 (22.4%) of the 185 patients with post-PEP test. Zidovudine (AZT) + 3TC + ATV-r was the most effective (95.5%, n = 63 of 66) regimen, while TDF + emtricitabine (FTC) + ritonavir-boosted lopinavir (LPV/r) was the most expensive ($23.66). With an ACER of $8.110/HIV infection prevented (95% CI: $8.052-$8.168), TDF + 3TC + efavirenz (EFV) was the most cost-effective regimen.

Conclusions:
AZT + 3TC + LPV/r was the most effective regimen, while TDF + FTC + ATV/r was the most expensive. However, TDF + 3TC + EFV combination was the most cost-effective regimen used in providing PEP service to HIV patients in Nigerian hospitals.