Background:
Findings from seroprevalent cohorts suggest that weight gain after ART initiation is greater with regimens containing Integrase Strand Transfer Inhibitors (INSTI) than with other antiretrovirals. We investigate weight trends among individuals initiating ART within one year of seroconversion (SC).
Methods:
Included individuals from the CASCADE Collaboration seroconverted 1997-2022, were ≥16 years, had HIV- to HIV+ test interval ≤1 year or other laboratory evidence of SC, and initiated ART ≤12 months from SC. Weight changes from baseline (censored after switching ART class) were analyzed with piecewise linear mixed models.
Results:
6482 (22.7%) of 28556 individuals were included (2814, 1999 and 1669 with INSTI, boosted PI or NNRTI regimens, respectively). Most acquired HIV through sex between men (79.3%), and 8.3% men and 8.9% women through heterosexual contact. Median (IQR) age at SC was 34 (27, 43) years, CD4 at ART initiation 451 (320, 620) cells/μl and follow-up time 1.4 (0.3, 3.6) years. Weight changes differed significantly (p<0.001) by ART class and baseline BMI. In the first 6 months, weight gains were generally most pronounced among those on INSTIs, regardless of baseline weight. This trend remained by 3 years for BMI categories <30, although those receiving boosted PIs also experienced weight gain. 'Typical individuals' (Figure) had significant weight gains with all three ART classes after 3 years except for baseline BMI ≥30. Individuals with BMI 18.5-29.9 gained weight significantly faster with INSTIs compared to other ART classes. Overall, 16% with BMI 18.5-24.9 and 11% with BMI 25-29.9 on INSTIs gained >10% of their baseline weight after 3 years (9% and 8% for boosted PIs; 7% and 6% for NNRTIs). Significant differences in initial (0-6 months) rate of weight gain were observed between INSTI regimens (p<0.001). Bictegravir or Elvitegravir + TAF backbone were associated with the fastest rates. Dolutegravir without TAF/TDF, and Elvitegravir + TDF were associated with the slowest. Estimated (95% CI) weight gains after 3 years among 'typical individuals' with BMI 18.5-24.9 were 5.6 (4.5, 6.6), 4.4 (3.5, 5.4), 3.6 (2.8, 4.4), and 3.4 (2.5, 4.2) kgs, respectively.
Conclusions:
As reported in seroprevalent cohorts, Bictegravir and Elvitegravir combined with TAF were associated with the fastest increases in weight. Given that ART was initiated soon after SC, it is unlikely that this is a return to health phenomenon, although the effect of unmeasured confounders can’t be disregarded.
