Differences in HIV natural history among African and non-African seroconverters in Europe and seroconverters in sub-Saharan Africa

Abstract

Introduction: It is unknown whether HIV treatment guidelines, based on resource-rich country cohorts, are applicable to African populations.

Methods: We estimated CD4 cell loss in ART-naïve, AIDS-free individuals using mixed models allowing for random intercept and slope, and time from seroconversion to clinical AIDS, death and antiretroviral therapy (ART) initiation by survival methods. Using CASCADE data from 20 European and 3 sub-Saharan African (SSA) cohorts of heterosexually-infected individuals, aged ≥15 years, infected ≥2000, we compared estimates between non-African Europeans, Africans in Europe, and Africans in SSA.

Results: Of 1,959 (913 non-Africans, 302 Europeans-African origin, 744 SSA), two-thirds were female; median age at seroconversion was 31 years. Individuals in SSA progressed faster to clinical AIDS but not to death or non-TB AIDS. They also initiated ART later than Europeans and at lower CD4 cell counts. In adjusted models, Africans (especially from Europe) had lower CD4 counts at seroconversion and slower CD4 decline than non-African Europeans. Median (95% CI) CD4 count at seroconversion for a 15-29 year old woman was 607 (588-627) (non-African European), 469 (442-497) (European-African origin) and 570 (551-589) (SSA) cells/µL with respective CD4 decline during the first 4 years of 259 (228-289), 155 (110-200), and 199 (174-224) cells/µL (p<0.01).

Discussion: Despite differences in CD4 cell count evolution, death and non-TB AIDS rates were similar across study groups. It is therefore prudent to apply current ART guidelines from resource-rich countries to African populations.

Figure 1. Predicted average CD4 cell count evolution by study group (women, aged 15–29 years at seroconversion, enrolled into cohorts within 6 months of seroconversion).

Figure 2. Kaplan-Meier curves of the cumulative probability of a) clinical AIDS, b) clinical AIDS (excluding TB cases) c) Death, d) cART initiation and e) loss to follow-up (≥12 months) before cART initiation or AIDS onset.

Curves shown by study group: individuals of non-African origin (solid line) or of African origin (dotted line) in European cohorts and individuals in SSA cohorts (dashed line).