Impact of Body Mass Index on Clinical Outcomes After Thrombectomy for Acute Ischemic Stroke in a Japanese Population.

Background: We aimed to determine the impact of body mass index (BMI) on outcomes in Japanese patients undergoing mechanical thrombectomy for acute ischemic stroke using a Japanese obesity cutoff. Methods: The study sample consisted of consecutive patients undergoing thrombectomy for acute ischemic stroke at our institution from January 2020 to December 2023. Patients were divided into 3 groups by BMI: low (<18.5 kg/m2), normal (18.5-24.9 kg/m2), and high (≥25 kg/m2). Baseline patient characteristics and procedural, safety, and clinical outcomes were compared between the 3 groups. Results: A total of 309 patients were analyzed, of whom 39 (12.6%) had a low BMI, 201 (65.0%) had a normal BMI, and 69 (22.3%) had a high BMI. There were significant differences in the nutritional status index scores between the 3 groups, namely the Geriatric Nutritional Risk Index, the Controlling Nutritional Status, and the Prognostic Nutritional Index. However, there were no significant differences in procedural and safety outcomes. There was no significant difference in the proportion of patients with a modified Rankin Scale score of 0-2 at 90 days between the 3 groups. However, there were significant differences in the proportion of patients with a modified Rankin Scale score of 0-3 (overall 51.8%; low 35.9%, normal 51.7%, high 60.9%; P = 0.045) and mortality (overall 14.6%; low 30.8%, normal 13.4%, high 8.7%; P = 0.006). A multivariate logistic regression analysis revealed that the odds of mortality at 90 days were significantly higher in the low BMI groups than in the normal BMI group (adjusted odds ratio, 2.69; 95% CI, 1.16-6.26; P = 0.02). Conclusions: In a Japanese population, low BMI may be associated with poor clinical outcomes after thrombectomy for acute ischemic stroke, including increased mortality.