Prevalence and Factors Associated with Opportunistic Infections Among Adults with Advanced HIV Disease Attending a Tertiary Hospital in NorthCentral Nigeria: A Retrospective Cross-Sectional Study, 2023–2025

Background: Opportunistic infections (OIs) remain an important cause of morbidity among adults with advanced HIV disease (AHD). We assessed documented OIs and exploratory associations in a tertiary HIV clinic in North-Central Nigeria. Methods: This retrospective cross-sectional study reviewed targeted clinic records from 2023–2025. Of 150 records screened, 144 adults had documented CD4 counts <200 cells/µL and met eligibility criteria. OIs active at the index assessment or diagnosed within 14 days were counted. Crude prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated; no adjusted models were fitted. Results: Fifty-two participants had ≥1 documented OI (36.1%; Wilson 95% CI 28.7–44.2%), accounting for 65 diagnoses. Pulmonary tuberculosis (n=24), oral candidiasis (n=16), and recorded cryptococcal meningitis (n=9) predominated. OI prevalence was 62.5%, 40.9%, and 20.6% at CD4 counts <50, 50–99, and 100–199 cells/µL, respectively (trend P<0.001). ART naïve participants had higher recorded OI prevalence than ART-experienced participants (PR 1.91; 95% CI 1.25–2.92). Among 89 ARTexperienced participants with complete adherence data, poor versus good recorded adherence was associated with higher OI prevalence (PR 2.04; 95% CI 1.02–4.08), although the inference was sensitive to missing-data assumptions. Conclusions: Documented OIs were frequent in this selected hospital sample, especially at lower CD4 counts. Targeted selection, heterogeneous diagnostic certainty, confounding, and uncertain temporal ordering preclude population-wide or causal inference.