Late HIV Diagnosis and Its Impact on Immune Recovery and Clinical Outcomes: A Retrospective Study From Turkey

Background Late diagnosis of HIV remains a critical barrier to effective treatment and improved long-term outcomes. Individuals presenting with low CD4+ T cell counts at diagnosis are at greater risk for opportunistic infections, hospitalization, and mortality. This study aimed to compare clinical, immunological, and virological outcomes among early and late presenters, and to identify factors associated with virologic failure. Methods We conducted a retrospective cohort study of 200 patients newly diagnosed with HIV between 2012 and 2019. Participants were categorized into three diagnostic groups based on baseline CD4+ T cell counts: early diagnosis (>350 cells/mm 3 ), late diagnosis 1 (200-350 cells/mm 3 ), and late diagnosis 2 (<200 cells/mm 3 ). Baseline demographics, laboratory markers, clinical outcomes, and treatment responses were compared. Logistic regression was used to evaluate predictors of virologic failure at 6 months. Results Late presenters accounted for 71% of the cohort and were more likely to be older, female, unmarried, and have lower education levels. They exhibited significantly lower CD4+ counts, CD4/CD8 ratios, and higher HIV RNA levels at diagnosis ( P < .001). Opportunistic infections, hospitalization, and mortality were significantly more common in the late diagnosis 2 group ( P < .001). Although virologic suppression was achieved in most patients, immune recovery was significantly impaired in those diagnosed late. Antiretroviral therapy (ART) initiation after 2015 was independently associated with lower risk of virologic failure (OR: 0.39; P = .039). Conclusion Late HIV diagnosis is associated with increased clinical morbidity and impaired immune reconstitution, even in virologically suppressed individuals. Early detection, prompt ART initiation, and routine CD4/CD8 monitoring are essential to optimize outcomes. Public health interventions targeting social determinants may help reduce delays in diagnosis and improve equity in HIV care.