Protective effect of high body mass index in elderly critically ill with severe COVID-19 pneumonia

The "obesity paradox"-reduced mortality in obese patients-in critically ill individuals remains a topic of conflicting evidence, but it appears to be more pronounced in the elderly. Our study aims to investigate the predictive significance of body weight in relation to the mortality of critically ill elderly individuals with severe COVID-19 pneumonia. Consecutive patients aged >70 years, admitted to intensive care unit (ICU) for SARS-CoV-2 severe pneumonia were included in the final analysis. Among various data collected, body mass index (BMI) was recorded upon admission, and both classical statistics and logistic regression modeling were applied to assess the relation of BMI with ICU mortality. Our cohort comprised 102 patients, with an average age of 77 +/- 5 years, of whom 26% were female. The average length of ICU stay was 11.4 +/- 9.2 days, and the average BMI was 29.3 +/- 5.2 kg/m(2). High-flow oxygenation, non-invasive ventilation, and invasive mechanical ventilation were used to support 33%, 35%, and 68% of patients, respectively. ICU mortality was observed in 50.0% of cases, with survivors having a shorter ICU stay compared to non-survivors (9.1 +/- 8.5 vs. 13.6 +/- 9.4 days, p = 0.01). Furthermore, survivors exhibited higher BMI values compared to non-survivors (30.5 +/- 5.6 vs. 28.1 +/- 4.5 kg/m(2), p = 0.02), with a higher proportion of survivors having a BMI >30 kg/m(2) (51% vs. 29%, Chi-square p = 0.025). Adjusted for gender and chronic diseases, BMI >30 kg/m(2) measured at admission was associated with lower ICU mortality (odds ratio (OR): 0.33, p = 0.04) and lower hospital mortality (OR: 0.21, p = 0.024). Overall, our findings suggest that higher BMI is correlated with lower mortality and shorter ICU stays in elderly critically ill patients with severe COVID-19 pneumonia.