Department of Medicine, Stanford University School of Medicine, Stanford, California.
Department of Medicine, Stanford University School of Medicine, Stanford, California.
J Ren Nutr. 2019 Nov;29(6):521-528. doi: 10.1053/j.jrn.2018.11.011. Epub 2019 Jan 29.
Obesity, defined by body mass index (BMI), is associated with lower mortality risk in patients with chronic kidney disease (CKD). BMI and % body fat (%BF) are confounded by muscle mass, while DXA derived fat mass index (FMI) overcomes this limitation. We compared the associations between obesity and mortality in persons with CKD using multiple estimates of adiposity, and determined whether muscle mass, inflammation and weight loss modify these associations.
Obesity was defined using BMI and DXA-derived FMI and %BF cut-offs in 2,852 NHANES participants with CKD from 1999-2006 and linked to the National Death Index with follow up through 2011. Cox proportional hazards models assessed associations between mortality and measures of obesity.
Obesity based on FMI and continuous variables, FMI, BMI and %BF were associated with lower mortality. The protective association of obesity was less pronounced among participants with higher muscle mass and was no longer significant after adjustment for prior weight loss. Inflammation did not modify these associations.
We observed lower mortality associated with higher fat mass, particularly among persons with lower muscle mass. The prevalence of >10% weight loss was half as common among obese compared to non-obese participants and confounded these associations.
体重指数（BMI）定义的肥胖与慢性肾脏病（CKD）患者的低死亡率风险相关。BMI 和体脂肪百分比（%BF）受肌肉质量的影响，而 DXA 衍生的脂肪质量指数（FMI）克服了这一限制。我们使用多种肥胖指标比较了 CKD 患者中肥胖与死亡率之间的关联，并确定肌肉质量、炎症和体重减轻是否会改变这些关联。
使用 BMI 和 DXA 衍生的 FMI 和 %BF 切点定义肥胖，纳入 1999-2006 年有 CKD 的 2852 名 NHANES 参与者，并与 2011 年之前的国家死亡指数相关联。Cox 比例风险模型评估了死亡率与肥胖指标之间的关联。
基于 FMI 和连续变量、FMI、BMI 和 %BF 的肥胖与较低的死亡率相关。在肌肉质量较高的参与者中，肥胖的保护作用不太明显，并且在调整了先前的体重减轻后，这种关联不再显著。炎症并没有改变这些关联。
我们观察到与更高的脂肪量相关的死亡率较低，尤其是在肌肉质量较低的人群中。与非肥胖参与者相比，肥胖参与者的体重减轻超过 10%的发生率要低一半，并且混淆了这些关联。
