Several studies have shown an increase in weight in HIV-positive people receiving some contemporary antiretrovirals (ARV). We assess the effect of changes in body mass index (BMI), from different baseline BMI levels, on the risk of cardiovascular disease (CVD) and diabetes mellitus (DM).
We followed D:A:D study participants on ARV therapy from their first BMI measurement (baseline) to the first endpoint or earliest of 1/2/2016 or 6 months after last follow-up. The endpoints were CVD (composite of myocardial infarction/stroke/invasive cardiovascular procedure) and DM. Participants were stratified according to their baseline BMI as <20, 20-24.9, 25-29.9 and >30 kg/m2. BMI was lagged by 1 year, and changes from baseline BMI were calculated for each participant, with values carried forward. Poisson regression models were used, adjusted for baseline BMI and key confounders that did not lie on the causal pathway for each outcome, with BMI change fitted as a time varying covariate.
We included 43,011 participants with 2,104 CVD and 1,583 DM events over 365,287 and 354,898 person years of follow up (rate:CVD 5.8/1000 (95% confidence interval (CI) 5.5–6.0); DM 4.5/1000 (95% CI 4.2–4.7)). Participants were largely male (74%) with baseline mean age of 40 years and baseline median BMI of 23.0 (IQR: 21.0- 25.3). Risk of CVD by change in BMI from baseline, stratified by baseline BMI strata are shown in Figure 1a with little evidence of an increased risk of CVD with an increased BMI in any baseline BMI strata. Overall there was no statistically significant interaction between baseline BMI strata and BMI change (p=0.16). There was some evidence of an increased rate of CVD with a decrease in BMI of more than 2 kg/m2, especially in those with a baseline BMI<20 kg/m2. An increase in BMI was associated with an increased risk of DM across all baseline BMI strata (Figure 1b).
While increases in BMI across all levels of baseline BMI were not associated with an increased risk of CVD, such changes were consistently associated with increased risk of DM. There was also some evidence of an increased risk of CVD with a decrease in BMI. The extent to which these results apply to HIV-positive people with increased weight while receiving contemporary ARVs are uncertain.