Rate of CD4 decline and HIV-RNA change following HIV seroconversion in men who have sex with men: a comparison between the Beijing PRIMO and CASCADE cohorts.

Objective: Little is known about the natural history of the HIV infection in men who have sex with men (MSM) in China. Methods: We compared changes in CD4(+) T-cell count and HIV-RNA following seroconversion before starting antiretroviral therapy between MSM in China and in resource-rich countries using data from the Beijing PRIMO cohort and Concerted Action on SeroConversion to AIDS and Death in Europe (CASCADE), respectively. Linear mixed models were used to compare rates of CD4 decline (cubic root scale) and changes in HIV-RNA (log(10) scale) in the first 3 years following seroconversion. Results: For 131 PRIMO and 3171 CASCADE MSM infected in 2001-2010, estimated CD4(+) T-cell count at seroconversion was lower in PRIMO (504 cells/mm(3); 95% confidence interval: 463 to 547) compared with CASCADE (554 cells/mm(3); 544 to 564). CD4 decline was significantly faster for PRIMO men [-0.59 (-0.72 to -0.47) and - 0.41 (-0.44 to -0.38) cubic root of CD4 count/year for PRIMO and CASCADE, respectively], even after restricting to subtype B (P = 0.01). HIV-RNA at seroconversion was lower in PRIMO compared with CASCADE MSM [difference 0.425 log(10)/mL (0.249 to 0.603), P < 0.001]. After the first year of seroconversion, PRIMO MSM experienced a faster increase in HIV-RNA [0.830 log(10)/mL per year; (0.484 to 1.168)] compared with CASCADE MSM [0.018 (- 0.035 to 0.067)] (P < 0.001). Conclusions: CD4 decline and HIV-RNA increase are faster between MSM in China compared with MSM from resource-rich settings. Whether this is due to differences in host immunity or viral characteristics requires further exploration.