BMI对衰弱老年人全因死亡率影响的剂量-反应Meta分析

Efficacy of BMI on all-cause mortality in frail elderly:a dose-response meta-analysis

目的系统评价体质量指数(BMI)对衰弱老年人全因死亡率是否存在剂量-反应关系。方法计算机检索PubMed、EMbase、Web of Science、CBM、VIP、WanFang Data和CNKI数据库,搜集关于BMI对衰弱老年人死亡率影响的队列研究,检索时限均从建库至2019年11月。由2名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用Stata 15.0软件使用限制性立方样条函数和广义最小二乘估计方法(GLST)分析BMI对衰弱老年人死亡率影响的剂量-反应关系。结果共纳入4个前瞻性队列研究,包括12861例衰弱老年人。Meta分析结果显示:与正常BMI的衰弱老年人相比,超重[HR=0.80,95%CI(0.74,0.88),P<0.001]和肥胖[HR=0.89,95%CI(0.79,1.00),P=0.047]的衰弱老年人的全因死亡率更低。剂量-反应Meta分析提示:BMI与衰弱老年人全因死亡率间存在非线性关系(非线性检验P=0.035),BMI 27.5~31.9 kg/m2时衰弱老年人全因死亡率最低。对于线性趋势,BMI小于27.5 kg/m2时BMI每增加1 kg/m2,衰弱老年人的全因死亡风险降低4%[RR=0.96,95%CI(0.90,1.03),P=0.320];BMI大于27.5 kg/m2时BMI每增加1 kg/m2,衰弱老年人的全因死亡风险增加4%[RR=1.04,95%CI(1.03,1.05),P<0.001]。结论当前证据表明,BMI与衰弱老年人的全因死亡率间呈明显非线性关系且存在肥胖悖论,BMI 27.5~31.9 kg/m2时衰弱老年人全因死亡率最低。受纳入研究数量和质量的限制,上述结论尚待更多高质量研究予以验证。

Objective To systematically review the dose-response relationship between body mass index(BMI)and all-cause mortality in the elderly with frailty.Methods PubMed,EMbase,Web of Science,CNKI,VIP,WanFang Data,and CBM databases were electronically searched to collect cohort studies on the association of BMI and mortality in frail adults from inception to November 2019.Two reviewers independently screened literature,extracted data and assessed risk bias of included studies;Stata 15.0 software was then used to analyze the dose-response analysis of BMI and mortality by restricted cubic spline function and generalized least squares method.Results A total of 4 cohort studies involving 12861 frail adults were included.Meta-analysis results showed that compared with normal BMI,the frail elderly who were overweight(HR=0.80,95%CI 0.74 to 0.88,P<0.001)and obese(HR=0.89,95%CI 0.79 to 1.00,P=0.047)had lower all-cause mortality.The results of dose-response meta-analysis showed that there was a non-linear relationship between BMI and all-cause mortality in the elderly with frailty(P value for nonlinearity was 0.035),for which the elderly with frailty had a BMI nadir of 27.5-31.9 kg/m2.For linear trends,and when BMI was less than 27.5 kg/m2,the risk of allcause death was reduced by 4%for every 1 kg/m2 increase in BMI(RR=0.96,95%CI 0.90 to 1.03,P=0.320),when BMI was greater than 27.5 kg/m2,the risk of all-cause death increased by 4%for every 1 kg/m2 increase in BMI(RR=1.04,95%CI1.03 to 1.05,P<0.001).Conclusions There is a paradox of obesity and a significant nonlinear relationship between BMI and all-cause mortality in the frailty elderly,with the lowest all-cause mortality in the frailty elderly at BMI 27.5-31.9 kg/m2.Due to limited quality and quantity of the included studies,more high quality studies are needed to verify the above conclusions.