Association between body mass index and cardiovascular events in elderly hypertensive patients

Abstract

Objective To examine the association between body mass index(BMI)and cardiovascular events in elderly hypertensive patients. Methods A total of 2267 elderly(age≥65)hypertensive patients undergoing long-term physical examination at Henan Province People's Hospital were included in this cohort study, and were divided into three groups: an underweight group(BMI≤18.4 kg/m2, n=125), a normal group(BMI=18.5-23.9 kg/m2, n=912), an overweight group(BMI=24.0-27.9 kg/m2, n=884), and an obesity group(BMI≥28.0 kg/ m2, n=346)for a six-year follow-up period.The incidences of cardiovascular events were collected and analyzed for all groups.The Cox proportional hazards regression model was used to analyze all possible risk factors for all-cause deaths and cardiovascular events. Results There were 2 267 patients, including 1 260 male and 1 007 female patients, with a mean age of(75.7±6.1)years.The Cox proportional hazards regression model showed that being underweight(BMI≤18.4 kg/m2)was a risk factor with a 1.8 times higher risk for all-cause death and a 1.5 times higher risk for cardiovascular death than having a normal weight(RR=1.8, 95%CI: 1.3-2.6; RR=1.5, 95%CI: 1.3-1.7). Being overweight(BMI=24-27.9kg/m2)was a protective factor with a 0.6 times lower risk for all-cause death and a 0.7 times lower risk for cardiovascular death, compared with the normal group(RR=0.6, 95%CI: 0.5-0.8; RR=0.7, 95%CI: 0.6-0.9). Obesity(BMI≥28.0kg/m2)was a protective factor for cardiovascular death with a lower relative risk of 0.9, compared with the normal group(RR=0.9, 95%CI: 0.9-1.0). Conclusions Paradoxically, being overweight is associated with a low mortality and a favorable cardiovascular prognosis, whereas being underweight carries a poor prognosis in elderly hypertensive patients. Key words: Hypertension; Body mass index; Factor analysis, statistical