Estimating the time period between infection and diagnosis based on CD4+ counts at first diagnosis among HIV-1 antiretroviral naïve patients in Nigeria

Abstract

Introduction: CD4⁺ T-cell levels are an important criterion for categorizing HIV-related clinical conditions. Late diagnosis of infection contributes to poor medical outcomes and the continuation of viral transmission. This population-based cohort study in north central Nigeria reports the initial CD4⁺ lymphocyte counts at the time of first HIV diagnosis and determines the approximate time interval when HIV infection was acquired..

Methodology: Confirmed HIV-1 infected individuals (n = 588) for whom the dates of first HIV diagnosis were known were enrolled in this study. CD4⁺ lymphocyte counts were measured using a Fluorescence Activated Cell Sorter (FACS) platform that automatically quantifies CD4⁺ lymphocytes as absolute numbers of lymphocytes per μL of blood. The estimated time interval between HIV infection and time of first HIV diagnosis was determined as a function of the CD4⁺ lymphocytes' decay rate per calendar year.

Results: The results showed that 22.1% and 49.7% of HIV-infected individuals present late with advanced (CD4⁺: 200-349 cells/mL) and severe (CD4⁺: < 200 cells/mL) immunosuppression respectively, while only 12.1% present with CD4⁺ 500 cells/mL and 16.2%with CD4⁺ between 350-499 cells/mL. Mean CD4⁺ counts for females were higher when compared to those of males (p > 0.05), The time interval between HIV infection and first diagnosis was approximately 6.1 years for males and 7.3 years for females.

Conclusion: The majority of HIV-infected individuals in this study accessed health care at late stages of infection, suggesting many HIV-infected individuals in Nigeria are unaware of their HIV status. More efficient programs for early diagnosis of HIV to prevent transmission are urgently required.