老年高血压患者体质指数对心血管事件的影响

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

目的分析老年高血压患者体质指数（BMI）对心血管事件的影响。方法采用队列研究方法，对河南省人民医院长期体检的2267例老年高血压患者按BMI不同水平分组：低体重组（BMI≤18．4kg／m^2）125例，正常组（BMI：18．5～23．9kg／m^2）912例、超重组（BMI：24．0～27．9kg／m^2）884例和肥胖组（BMI≥28．0kg／m^2）346例。随访6年，调查心血管事件出现情况，分析不同BMI水平全因死亡及心血管事件的差异，运用Cox比例风险回归模型分析全因死亡及心血管事件可能的危险因素。结果2267例高血压患者平均年龄（75．7±6．1）岁，其中男性1260例，女性1007例。Cox比例风险回归模型提示，低体重是全因死亡及心血管死亡的危险因素，是正常体重者全因死亡及心血管死亡发生风险的1．8倍（RR=1．8，95％CI：1．3～2．6）和1．5倍（RR=1．5，95％CI：1．3～1．7）；超重是全因死亡及心血管死亡的保护因素，全因死亡及心血管死亡的风险为正常体重者的60％（RR=0．6，95％CI：0．5～0．8）和70％（RR=0．7，95％CI：0．6～0．9）；肥胖是心血管死亡的保护因素，心血管死亡的风险为正常体重者的90％（RR=0．9，95％CI；0．9～1．0）。结论在老年高血压患者中，超重患者有更低的病死率和更好的心血管预后，存在肥胖矛盾现象，低体重者预后最差，超重者预后最好。

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/m^2 , n= 125）, a normal group（BMI= 18.5-23.9 kg/m^2 , n= 912）, an overweight group（BMI= 24.0-27.9 kg/m^2 , n= 884）, and an obesity group（BMI≥28.0 kg/m^2 , 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/m^2 ）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 ： 24-27.9 kg/m^2） 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/m^2）was a protective factor for cardiovascular death with a lower relative risk of 0.9,compared with the normal group（RR=0.9,950/00 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.