Obesity the Paradox in Cardiovascular Disease and Critical Illness: A Narrative Review

Background: Obesity, affecting approximately 20% of intensive care unit admissions and a substantial proportion of cardiovascular disease patients, is traditionally recognized as a major risk factor for adverse health outcomes (1). The "obesity paradox" describes the counterintuitive observation of improved survival in overweight and mildly obese patients with established cardiovascular disease or critical illness. Objective: To comprehensively examine the obesity paradox in cardiovascular disease and critical illness, evaluating epidemiological evidence, mechanistic hypotheses, methodological limitations, and therapeutic implications. Methods: A systematic literature search was conducted using PubMed, MEDLINE, Embase, and Cochrane Library databases for articles published between January 2015 and March 2026. Search terms included "obesity paradox," "body mass index," "cardiovascular disease," "heart failure," "critical illness," "sepsis," and "mortality." Narrative synthesis was performed on included studies. Conclusion: The obesity paradox is a complex phenomenon with plausible biological underpinnings but significant methodological limitations. It should not be interpreted as evidence against weight management; rather, it highlights the need for nuanced, phenotype-specific approaches incorporating body composition and fitness assessment.