The paradox prevails: Outcomes are better in critically ill obese patients regardless of the comorbidity burden.

During critical illness, obese patients have better outcomes compared to patients with normal BMI, and this is known as the obesity paradox. The difference in comorbidity burden have been implied to be responsible for the paradox. We performed a retrospective review from 2001 to 2012 of critically ill patients from the Medical Information Mart for Intensive Care database. We included 11,433 patients and classified them according to body mass index (BMI) and comorbidity burden (Elixhauser comorbidity measure). The odds of inpatient mortality were lower in obese patients compared to patients with normal BMI; in group with the least comorbidity score (Elixhauser <0) [OR: 0.47, CI (0.28-0.80), p-value 0.006] and higher comorbidity scores, (Elixhauser 1-5) [(OR: 0.66, CI (0.46-0.95), p-value 0.02)] and (Elixhauser 6-13) [OR: 0.69, CI (0.53-0.92), p-value 0.01]. 30-day mortality was also significantly lower in obese patients, in groups with the lowest (Elixhauser <0) [OR:49, CI (0.31-0.77), p-value 0.002] as well as the highest comorbidity burden (Elixhauser >14) [OR:0.59, CI (0.45-0.77), p-value <.001]. Subgroup analysis in patients with various comorbidities showed better outcomes in obese patients. These findings show that the decreased odds of mortality in critically ill obese patients is independent of the comorbidity burden or type of comorbidity.