Effects of body mass index (BMI) on cardiovascular events are inconsistent. We aimed to investigate the association of BMI with cardiovascular events in hypertensives with obstructive sleep apnea (OSA).

Hypertensives with OSA diagnosed with polysomnography between 2011 and 2013 in UROSAH cohort were followed up till Jan 2021. Outcomes were non-fatal cardiovascular events and cardiac death. Cox regression was used to estimate the relationship of continuous and categorical BMI with total and specific outcomes. Sensitivity analyses were performed by excluding those on OSA treatment or underweight patients. Stratified analyses were conducted by parameters including sex and age.

2239 hypertensives with OSA were included with 405 normal weight (BMI<25 kg/m²), 1164 overweight (25–29.9 kg/m²) and 670 obesity (≥30 kg/m²). 206 non-fatal cardiovascular events and 18 cardiac death were recorded during 6.6 years follow-up. Compared with normal weight group, overweight (HR=1.53, 95%CI: 1.01–2.32, P = 0.047) and obesity groups (1.85, 1.19–2.86, P = 0.006) showed increased risk for cardiovascular events, significant in obesity group and marginal in overweight group in fully-adjusted model. In specific events, obesity showed significantly elevated HR for non-fatal cardiovascular events (1.64, 1.04–2.60, P = 0.035). Continuous BMI showed significantly increased HR for total and specific events in all models. Sensitivity analysis yielded consistent results. In stratification analysis, stronger association between obesity and cardiovascular events was observed in the young (HR=5.97, P interaction=0.030).

BMI is in positive association with cardiovascular events in hypertensives with OSA, emphasizing importance of maintaining healthy BMI for prevention of adverse events in this population, on the basis of guideline-recommended treatment.