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BODY MASS INDEX AND THE RISK OF SERIOUS NON-AIDS EVENTS: THE D:A:D STUDY
Amit C. Achhra1, Caroline Sabin2, Lene Ryom3, Antonella d'Arminio Monforte4, Stephane de Wit5, Andrew Phillips2, Christian Pradier6, Jens D. Lundgren7, Matthew Law1
1Kirby Inst, Sydney, Australia,2Univ Coll London, London, UK,3CHIP, Copenhagen, Denmark,4Univ of Milan, Milan, Italy,5Univ Libre de Bruxelles, Brussels, Belgium,6Nice Univ Hosp, Nice, France,7Univ of Copenhagen, Copenhagen, Denmark
Body mass index (BMI) (weight (kg)/ height(m2)) is a potentially modifiable risk factor for several serious non-AIDS events (SNAEs). However the relationship between BMI and SNAEs in HIV-positive individuals in not well understood.
We followed D:A:D study participants on antiretroviral therapy from their first BMI measurement to the first occurrence of a SNAE or 1/2/2014. The SNAEs of interest, all well-adjudicated, were cardiovascular disease (CVD- composite of myocardial infarction/stroke/invasive cardiovascular procedures); diabetes; non-AIDS-defining malignancies (NADM); BMI-associated cancers (composite of malignancies known to be associated with BMI in general population, including esophagus, pancreas, colon, rectum, breast, endometrium, kidney, thyroid and gallbladder); and all-cause mortality. BMI was time-updated and lagged by 1 year (i.e. there was at least 1 year time-gap between last BMI measurement and a SNAE, so as to minimize bias from reverse causation) and categorised at clinical cut-offs: 18.5, 23, 25, 27.5 and 30 kg/m2. Poisson regression models adjusted for key confounders for each SNAE were used.
During 295,147 person-years of follow-up (PYFU) in 41,149 included individuals, incidence/1000 PYFU of outcomes were: CVD (n=1398): 4.8; diabetes (n=3025): 10.2; NADM (n=1143): 3.9; BMI-cancers (n=184): 0.6 and all-cause mortality (n=3025): 10.2. Participants were largely male (73%) with baseline mean age of 40 years and baseline median BMI of 23.3 (IQR: 21.2- 25.7). A majority of follow-up was in BMI categories of 18.5-23 (41%), 23-25 (22%) and 25-27.5 (17%). Overall, BMI showed a statistically significant J-shaped relationship with the risk of all outcomes except diabetes (Table). There was a higher risk of CVD, NADM, and all-cause mortality at BMI levels <18.5 and at 18.5-23 (especially for NADM and all-cause mortality), compared to the BMI at 23-25. High BMI (>30), compared to that at 23-25, was associated with the higher relative risk of CVD, diabetes, BMI-cancers and possibly all-cause mortality. For diabetes, there was a linear increase in risk with increasing BMI. Results were not sensitive to lagging latest BMI by 2 years (data not shown).
We found that the low BMI, even at the levels of 18-23 and after being lagged by 1 year, was associated with higher short-term risk of CVD, NADM and all-cause mortality in this population. High BMI (>30) was a risk factor for CVD, diabetes, NADM and BMI-cancers.