低体格指数（BMI）が脳卒中アウトカムに及ぼす影響：傾向スコアマッチング解析

Body mass index (BMI) influences stroke outcomes, but the impact of being underweight remains understudied. This analysis examines whether underweight status (BMI < 19.9) is associated with worse post-stroke outcomes compared to ideal BMI (20-24.9). We aim to evaluate functional and clinical outcomes in stroke patients with low BMI versus those with ideal weight.

Using TriNetX data from the Mount Sinai Health System, we identified adult patients with ischemic stroke (ICD-10: I63) and categorized them based on BMI: ideal weight (BMI 20-24.9, n = 2,640) and underweight (BMI < 19.9, n = 1,610). Propensity score matching on demographics and comorbidities yielded two balanced cohorts of 1,600 patients each. We assessed outcomes over a 2-year follow-up, including modified Rankin Scale (mRS > 2), pneumonia, and survival probability using Kaplan-Meier analysis.

Underweight patients had a higher incidence of poor functional outcome (mRS > 2: 18.1 % vs 14.4 %; RR 1.26, p = 0.004), with a lower survival probability at 2 years (79.3 % vs 83.7 %; log-rank p = 0.002). Pneumonia occurred more frequently in the underweight group (8.8 % vs 6.9 %; p = 0.048). No significant differences were observed in rates of repeat stroke, motor deficits, or hemorrhagic transformation. Use of thrombolytics, thrombectomy, or need for intubation did not differ significantly.

Underweight status is associated with poorer functional outcomes, increased pneumonia risk, and reduced survival following ischemic stroke compared to patients with ideal BMI. These findings support the consideration of nutritional status in post-stroke care planning and risk stratification.