Obesity paradox and stroke: a narrative review

BACKGROUND: Despite obesity is an established risk factor for stroke, several studies reported a better outcome after stroke in obese and overweight patients. This counterintuitive finding, which was described in the whole spectrum of cardiovascular diseases, is known as obesity paradox. OBJECTIVE: This is a narrative overview on the obesity paradox and stroke. METHODS: We used as sources MEDLINE/PubMed, CINAHL, EMBASE, and Cochrane Library from inception to 2019, and selected papers that discussed the association of obesity with outcome and mortality after stroke. RESULTS: The majority of studies reported lower mortality rates and better functional outcome after stroke in obese and overweight patients compared with normal weight and underweight patients, suggesting the existence of an obesity paradox in stroke. However, available studies are limited by several major methodological concerns including absence of randomized trials, retrospective nature of most studies, assessment of obesity with body mass index (BMI), non-linear relationship between BMI and outcome, short follow-up period, and differences in co-morbid conditions and stroke characteristics. CONCLUSIONS: The existence of an obesity paradox in stroke is still controversial and further higher quality evidence is needed to clarify the relationship between obesity and stroke outcome. LEVEL OF EVIDENCE: Level V, narrative review.