Background There is evidence that frailty is an independent predictor of worse outcomes after stroke. Similarly, although obesity is associated with a higher risk for stroke, there are multiple reports describing improved mortality and functional outcomes in higher body mass index (BMI) patients in a phenomenon known as the obesity paradox. We investigated the effect of low BMI on outcomes after mechanical thrombectomy (MT).
Methods We conducted a retrospective analysis of 231 stroke patients who underwent MT at an academic medical center between 2020–2022. The patients’ BMI data were collected from admission records and coded based on the Centers for Disease Control and Prevention (CDC) obesity guidelines. Recursive partitioning analysis (RPA) in R software was employed to automatically detect a BMI threshold associated with a significant survival benefit. Frailty was quantified using the Modified Frailty Index 5 and 11.
Results In our dataset, by CDC classification, 2.6% of patients were underweight, 27.3% were normal BMI, 30.7% were overweight, 19.9% were class I obese, 9.5% were class II obese, and 10% were class III obese. There were no significant differences between these groups. RPA identified a clinically significant BMI threshold of 23.62 kg/m2. Independent of frailty, patients with a BMI ≤23.62 kg/m2 had significantly worse overall survival (P<0.001) and 90-day modified Rankin Scale (P=0.027) than patients above the threshold.
Conclusions Underweight patients had worse survival and functional outcomes after MT. Further research should focus on the pathophysiology underlying poor prognosis in underweight MT patients, and whether optimizing nutritional status confers any neuroprotective benefit.
- CT perfusion
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.
Contributors AF designed the study, collected data, analyzed the data, wrote and revised the manuscript. MS designed the study, contributed to writing of manuscript, and analyzed the data. SS collected data and analyzed the data. JN performed statistical analysis, contributed to writing of manuscript, and analyzed the data. DM designed the study, contributed to writing of manuscript, and analyzed the data. PM collected data, provided feedback and guidance. RP collected data, provided feedback and guidance. AD collected data, provided feedback and guidance. WC collected data, provided feedback and guidance. JW designed the study, provided feedback and guidance. JL collected data, provided feedback and guidance. JL is the guarantor of this study. All authors discussed the work and commented on the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.