Medical Student Oregon Health and Science University Portland, Oregon, United States
Introduction: Obesity is associated with a higher risk for stroke, yet multiple studies have suggested higher body mass index (BMI) patients have improved mortality and functional outcomes in a phenomenon known as the obesity paradox. There are multiple reviews and meta-analyses supporting the existence of the obesity paradox. However, the literature remains divided, particularly in regard to the relationship between BMI and stroke outcomes in patients who undergo mechanical thrombectomy (MT) or IV thrombolysis.
Methods: We conducted a retrospective analysis of 231 stroke patients who underwent MT at Oregon Health and Science University between 2020-2022. Patients’ BMI was collected from admission vitals and coded based on CDC obesity guidelines. Recursive partitioning analysis (RPA) was employed to automatically detect a BMI cutpoint associated with a significant survival benefit.
Results: In our dataset, 2.6% of patients were underweight, 27.3% were healthy weight, 30.7% were overweight, 19.9% were CDC class I, 9.5% were class II, and 10% were class III. Underweight patients had the worse post-procedure survival. Obese, overweight, and healthy weight patients had comparable survival. RPA analysis identified clinically significant BMI cutpoints of 20.8 and 41.4. Those with a BMI>41.4 had the best survival but not significantly better than patients between 20.8-41.4. The improved survival of high BMI patients supports the evidence for the obesity paradox.
Conclusion : In our single institution experience, the improved survival probability of high BMI patients treated with MT supports the existence of the obesity paradox. Healthy BMI patients by CDC guideline and our RPA cutpoint had similar survival to overweight and obese patients. Underweight patients by CDC definition and RPA stratification had the worst overall survival. In addition to considering the protective factors of high BMI, the obesity paradox should also focus our attention on the pathophysiology underlying poor prognosis in underweight MT patients.
