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


METHODS
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.


CONCLUSIONS
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.
Clinical Virology Laboratory, Innovative Biotech, Keffi/Abuja, Nigeria. cforbi79@hotmail.com
Joseph C
JC
Forbi
Thanda D
TD
Forbi
Simon M
SM
Agwale
D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D005260:Female; D005434:Flow Cytometry; D015658:HIV Infections / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008297:Male; D009549:Nigeria; D013997:Time Factors