Objective  

To investigate the possible impact of obesity on morbidity and mortality in intensive care unit (ICU) patients included in the European observational sepsis occurrence in acutely ill patients (SOAP) study.

Design  

Planned substudy from the SOAP database.

Setting  

One hundred and ninety-eight ICUs in 24 European countries.

Patients  

All patients admitted to one of the participating ICUs. Patients were classified, according to their body mass index (BMI), as underweight (<18.5 kg/m²), normal weight (18.5–24.9 kg/m²), overweight (25–29.9 kg/m²), obese (30–39.9 kg/m²), and very obese (≥40 kg/m²).

Measurements and results  

The BMI was available in 2,878 (91%) of the 3,147 patients included in the SOAP study; 120 patients (4.2%) were underweight, 1,206 (41.9%) had a normal BMI, 1,047 (36.4%) were overweight, 424 (14.7%) were obese, and 81 (2.8%) were very obese. Obese and very obese patients more frequently developed ICU-acquired infections than patients in lower BMI categories. Very obese patients showed a trend towards longer ICU [median (IQ): 4.1 (1.8–12.1) vs. 3.1 (1.7–7.2) days, P = 0.056) and hospital lengths of stay [14.3 (8.4–27.4) vs. 12.3 (5.1–24.4), days P = 0.077] compared to those with a normal BMI. However, there were no significant differences among the groups in ICU or hospital mortality rates. In a multivariate Cox regression analysis, none of the BMI categories was associated with an increased risk of 60-day in-hospital death.

Conclusion  

BMI did not have a significant impact on mortality in this mixed population of ICU patients.