Sutter Health, CPMC Comprehensive Stroke Care Center (Z.L.).
University of Southern California (N.S., M.E.).
Stroke. 2021 Jan;52(1):144-151. doi: 10.1161/STROKEAHA.119.027900. Epub 2020 Dec 4.
A survival advantage among individuals with higher body mass index (BMI) has been observed for diverse acute illnesses, including stroke, and termed the obesity paradox. However, prior ischemic stroke studies have generally tested only for linear rather than nonlinear relations between body mass and outcome, and few studies have investigated poststroke functional outcomes in addition to mortality.
We analyzed consecutive patients with acute ischemic stroke enrolled in a 60-center acute treatment trial, the NIH FAST-MAG acute stroke trial. Outcomes at 3 months analyzed were (1) death; (2) disability or death (modified Rankin Scale score, 2-6); and (3) low stroke-related quality of life (Stroke Impact Scale<median). Relations with BMI were analyzed univariately and in multivariate models adjusting for 14 additional prognostic variables.
Among 1033 patients with acute ischemic stroke, average age was 71 years (±13), 45.1% female, National Institutes of Health Stroke Scale 10.6 (±8.3), and BMI 27.5 (±5.6). In both unadjusted and adjusted analysis, increasing BMI was linearly associated with improved 3-month survival (=0.01) odds ratios in adjusted analysis for mortality declined across the BMI categories of underweight (odds ratio, 1.7 [CI, 0.6-4.9]), normal (odds ratio, 1), overweight (0.9 [CI, 0.5-1.4]), obese (0.5, [CI, 0.3-1.0]), and severely obese (0.4 [CI, 0.2-0.9]). In unadjusted analysis, increasing BMI showed a U-shaped relation to poststroke disability or death (modified Rankin Scale score, 2-6), with odds ratios of modified Rankin Scale score, 2 to 6 for underweight, overweight, and obese declined initially when compared with normal weight patients, but then increased again in severely obese patients, suggesting a U-shaped or J-shaped relation. After adjustment, including for baseline National Institutes of Health Stroke Scale, modified Rankin Scale score 2 to 6 was no longer related to adiposity.
Mortality and functional outcomes after acute ischemic stroke have disparate relations with patients' adiposity. Higher BMI is linearly associated with increased survival; and BMI has a U-shaped or J-shaped relation to disability and stroke-related quality of life. Potential mechanisms including nutritional reserve aiding survival during recovery and greater frequency of atherosclerotic than thromboembolic infarcts in individuals with higher BMI.
在包括中风在内的多种急性疾病中，观察到体重指数（BMI）较高的个体具有生存优势，这种现象被称为肥胖悖论。然而，之前的缺血性中风研究通常仅测试体重与结局之间的线性关系，而很少有研究调查中风后的功能结局除了死亡率。
我们分析了连续入组参加 NIH FAST-MAG 急性卒中试验的 60 个中心急性治疗试验的急性缺血性卒中患者。在 3 个月时分析的结局包括：（1）死亡；（2）残疾或死亡（改良 Rankin 量表评分 2-6）；以及（3）较低的卒中相关生活质量（中风影响量表＜中位数）。使用单变量和多元模型分析 BMI 与这些结局的关系，多元模型调整了 14 个额外的预后变量。
在 1033 名急性缺血性卒中患者中，平均年龄为 71 岁（±13），45.1%为女性，国立卫生研究院卒中量表评分为 10.6（±8.3），BMI 为 27.5（±5.6）。在未调整和调整分析中，BMI 呈线性增加，与 3 个月时的生存（比值比=0.01）呈正相关。调整分析中，死亡率的比值比随着 BMI 类别的变化而下降，体重不足（比值比，1.7 [95%CI，0.6-4.9]）、正常（比值比，1）、超重（0.9 [95%CI，0.5-1.4]）、肥胖（0.5 [95%CI，0.3-1.0]）和严重肥胖（0.4 [95%CI，0.2-0.9]）。在未调整分析中，BMI 与卒中后残疾或死亡（改良 Rankin 量表评分 2-6）呈 U 型关系，与正常体重患者相比，体重不足、超重和肥胖患者的改良 Rankin 量表评分 2-6 的比值比最初下降，但随后在严重肥胖患者中再次升高，提示呈 U 型或 J 型关系。在调整包括基线国立卫生研究院卒中量表后，改良 Rankin 量表评分 2-6 与肥胖程度不再相关。
急性缺血性卒中后死亡率和功能结局与患者的肥胖程度存在不同的关系。较高的 BMI 与生存率的增加呈线性相关；BMI 与残疾和卒中相关生活质量呈 U 型或 J 型关系。潜在的机制包括恢复期间营养储备有助于生存，以及 BMI 较高的个体中更常见的是动脉粥样硬化性而非血栓栓塞性梗死。
