Kim Sejoong, Jeong Jong Cheol, Ahn Shin Young, Doh Kibbeum, Jin Dong-Chan, Na Ki Young
Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
Department of Nephrology, Ajou University School of Medicine, Suwon, Korea.
Kidney Res Clin Pract. 2019 Mar 31;38(1):90-99. doi: 10.23876/j.krcp.18.0094.
Unlike patterns observed in the general population, obesity is associated with better survival among hemodialysis patients, which could be explained by reverse causation or illness-related weight loss. However, the time-varying effect of body mass index (BMI) on hemodialysis survival has not been investigated. Therefore, this study investigated the time-varying effect of BMI on mortality after starting hemodialysis.
In the present study, we examined Korean Society of Nephrology data from 16,069 adult patients who started hemodialysis during or after the year 2000. Complete survival data were obtained from Statistics Korea. Survival analysis was performed using Cox regression and a non-proportional hazard fractional polynomial model.
During the median follow-up of 8.6 years, 9,272 patients (57.7%) died. Compared to individuals with normal BMI (18.5-24.9 kg/m), the underweight group (< 18.5 kg/m) had a higer mortality hazard ratio (HR, 1.292; 95% confidence interval [CI], 1.203-1.387; < 0.001) and the overweight group (25.0-29.9 kg/m) had a lower mortality HR (0.904; 95% CI, 0.829-0.985; = 0.022). The underweight group had increasing HRs during the first 3 to 7 years after starting hemodialysis, which varied according to age group. The young obese group (< 40 years old) had a U-shaped temporal trend in their mortality HRs, which reflected increased mortality after 7 years.
The obese hemodialysis group had better survival during the early post-dialysis period, although the beneficial effect of obesity disappeared 7 years after starting hemodialysis. The young obese group also had an increased mortality HR after 7 years.
与普通人群中观察到的模式不同，肥胖与血液透析患者的更好生存率相关，这可能是由反向因果关系或疾病相关的体重减轻来解释的。然而，体重指数（BMI）对血液透析生存率的时变效应尚未得到研究。因此，本研究调查了BMI对开始血液透析后死亡率的时变效应。
在本研究中，我们检查了韩国肾脏病学会的数据，这些数据来自2000年期间或之后开始血液透析的16069名成年患者。完整的生存数据来自韩国统计局。使用Cox回归和非比例风险分数多项式模型进行生存分析。
在中位随访8.6年期间，9272名患者（57.7%）死亡。与BMI正常（18.5 - 24.9 kg/m）的个体相比，体重过轻组（< 18.5 kg/m）的死亡风险比（HR）更高（HR，1.292；95%置信区间[CI]，1.203 - 1.387；P < 0.001），超重组（25.0 - 29.9 kg/m）的死亡HR较低（0.904；95% CI，0.829 - 0.985；P = 0.022）。体重过轻组在开始血液透析后的前3至7年期间HR逐渐增加，且根据年龄组有所不同。年轻肥胖组（< 40岁）的死亡HR呈U形时间趋势，这反映了7年后死亡率增加。
肥胖的血液透析组在透析后早期有更好的生存率，尽管肥胖的有益效果在开始血液透析7年后消失。年轻肥胖组在7年后的死亡HR也增加。
