Timing of combined antiretroviral treatment initiation in male and female migrants living with HIV in Western Europe

Background: We evaluate differences in timing of cART (combined antiretroviral treatment) initiation by geographical origin in male and female HIV-positive patients in the Collaboration of Observational HIV Epidemiological Research Europe, a large European Collaboration of HIV Cohorts. Methods: We included individuals recruited in Western Europe between January 1997 and March 2013, with known geographical origin and at least 1 CD4(+) cell countmeasurement while cART-naive. Timing of cART was assessed through modified time-to-eventmethods, in which a scale of CD4(+) cell counts was used instead of time, with cART being the outcome. We estimated the median CD4(+) cell count at cART initiation (estimated CD4(+) levels at which the probability of having started cART is 50%) using Kaplan-Meier and adjusted hazard ratios of cART initiation using Cox regression. Results: Of 151 674 individuals, 110 592 (72.9%) were men. Median (95% confidence interval) CD4(+) cell count falls far below 250 cells/ml in all groups and was lowest in sub-Saharan African [SSA: 161 (158-167)], Caribbean men [161 (150-174)] and in Asian women [Asian Continent and Oceania: 185 (165-197)]. Among men, the adjusted probability of cART initiation was lower in migrants compared with natives, but differences depended on initial CD4(+) cell count. For example, in the group with more than 500 CD4(+) at recruitment, they were 45% (36-53%), 30% (17-40%) and 25% (19-30%) lower for Caribbean, Eastern European and SSA men, respectively. In women, no meaningful differences were observed between natives and most migrant groups. However, SSA women had a 31% (24-38%) higher probability of cART initiation when recruited at a CD4(+) more than 500 cells/ml and 9% (4-14%) lower when recruited at CD4(+) less than 100 cells/ml. Conclusion: Most migrant men initiate cART at lower CD4(+) cell count than natives, whereas this does not hold for migrant women