School of Veterinary & Life Sciences, Murdoch University, Perth, WA 6150, Australia; Fiona Stanley Hospital, Medical School, University of Western Australia, Perth, WA 6150, Australia; Department of Anaesthesia and Intensive Care, Prince of Wales Hospital, the Chinese University of Hong Kong, Hong Kong Special Administrative Region of China.
Obes Res Clin Pract. 2024 May-Jun;18(3):189-194. doi: 10.1016/j.orcp.2024.05.004. Epub 2024 Jun 11.
The relationship between body mass index (BMI) and outcomes in the acute care setting is controversial, with evidence suggesting that obesity is either protective - which is also called obesity paradox - or associated with worse outcomes. The purpose of this study was to assess whether BMI was related to frailty and biological age, and whether BMI remained predictive of mortality after adjusting for frailty and biological age.
Of the 2950 patients who had a biological age estimated on admission to the intensive care unit, 877 (30 %) also had BMI and frailty data available for further analysis in this retrospective cohort study.
Biological age of each patient was estimated using the Levine PhenoAge model based on results of nine blood tests that were reflective of DNA methylation. Biological age in excess of chronological age was then indexed to the local study context by a linear regression to generate the residuals. The associations between BMI, clinical frailty scale, and the residuals were first analyzed using univariable analyses. Their associations with mortality were then assessed by multivariable analysis, including the use of a 3-knot restricted cubic spline function to allow non-linearity.
Both frailty (p = 0.003) and the residuals of the biological age (p = 0.001) were related to BMI in a U-shaped fashion. BMI was not related to hospital mortality, but both frailty (p = 0.015) and the residuals of biological age (OR per decade older than chronological age 1.50, 95 % confidence interval [CI] 1.04-2.18; p = 0.031) were predictive of mortality after adjusting for chronological age, diabetes mellitus and severity of acute illness.
BMI was significantly associated with both frailty and biological age in a U-shaped fashion but only the latter two were related to mortality. These results may, in part, explain why obesity paradox could be observed in some studies.
在急性护理环境中，体重指数（BMI）与结果之间的关系存在争议，有证据表明肥胖要么具有保护作用（也称为肥胖悖论），要么与更差的结果相关。本研究的目的是评估 BMI 是否与虚弱和生物年龄有关，以及在调整虚弱和生物年龄后，BMI 是否仍然可以预测死亡率。
在 2950 名接受 ICU 入院时生物年龄估计的患者中，877 名（30%）也有 BMI 和虚弱数据，可用于本回顾性队列研究的进一步分析。
每位患者的生物年龄使用基于九项反映 DNA 甲基化的血液测试结果的 Levine PhenoAge 模型进行估计。然后通过线性回归将生物年龄超过实际年龄的部分与当地研究背景进行索引，以生成残差。首先使用单变量分析来分析 BMI、临床虚弱量表和残差之间的关联。然后通过多变量分析评估它们与死亡率的关联，包括使用 3 个结限制立方样条函数来允许非线性。
虚弱（p=0.003）和生物年龄的残差（p=0.001）都以 U 形方式与 BMI 相关。BMI 与医院死亡率无关，但虚弱（p=0.015）和生物年龄残差（每比实际年龄大 10 岁的 OR 为 1.50，95%置信区间 [CI] 为 1.04-2.18；p=0.031）与调整实际年龄、糖尿病和急性病严重程度后的死亡率相关。
BMI 与虚弱和生物年龄呈 U 形显著相关，但只有后两者与死亡率相关。这些结果可能部分解释了为什么在一些研究中可以观察到肥胖悖论。
