Obesity Linked to Increased Ventilator Duration, ARDS Risk in Sepsis Patients

Greater BMI scores are linked to longer ventilator needs and higher risk of acute respiratory distress syndrome.

Prevalence and severity of obesity is associated with an increased duration of ventilator use among patients presenting to the intensive care unit (ICU) with sepsis, according to new data.

An assessment originally planned for presentation at the American Thoracic Society (ATS) 2020 International Conference this week showed not only an associated between increased body mass index (BMI) and sepsis-based ventilator use—but a significant link between BMI and acute respiratory distress syndrome (ARDS) risk.

The findings, from a team of investigators at Marshall University, come at a time when reports of coronavirus 2019 (COVID-19) severity and hospitalization duration—particularly due to respiratory distress—are more significantly associated with obesity.

Investigators, led by Abdul Rana, MD, a resident at the Joan C. Edwards School of Medicine, noted that nearly 40% of adults aged ≥20 years in the US are currently obese. While the association between chronic disease and increased BMI is well-observed, its impact on acute conditions is not as well understood.

“Our aim was to study the impact of BMI)on the duration of ventilator use and development of ARDS among patients admitted in ICU with sepsis,” Rana and colleagues wrote.

The team conducted a retrospective cohort analysis using patients from the Mimic 3 database who were admitted to the ICU with sepsis. BMI was classified into the 5 classes defined by the World Health Organizations (WHO) criteria. Partial pressure of oxygen (PO2) and fraction of inspired oxygen (FiO2) were used to defined ARDS prevalence and severity.

Investigators used a Kruskal-Wallis test with Dunn’s post hoc analysis for continuous non-normally distributed data, as well as poisson regression analysis—with adjustments for age, sex, and sofa scores.

The 4224 patients included in the assessment were mostly male (57%), with varying classes of BMI among the septic ICU patients: 4% were underweight; 30% were normal weight; 31% were overweight; 26% were obese; and 9% were severely obese.

Rana and colleagues observed an associated duration of ventilator use with increase BMI in ICU-admitted patients (P <.0001). Obese and severely obese patients had a significantly longer duration of ventilator use compared to normal BMI patients (OR, 1.2; 95% CI, 1.03-1.40; P = .02 for obese) (OR, 1.5; 95% CI, 1.24-1.87; P <.001 for severely obese).

BMI was also associated with a significant risk of developing ARDS, investigators added (P = .01). When subcategorizing PO2/FiO2 ratio into mild (200-300), moderate (100-200), and severe (<100) scores, the risk of mild ARDS among obese and severely obese patients was significantly higher than among lower BMI patients (RR, 1.62; 95% CI, 1.18-2.23; P <.001 for obese) (RR 2.02; 95% CI, 1.31-3.13; P = .001 for severely obese).

Moderate ARDS was 71% more likely in obese patients (95% CI, 1.27-2.23; P <.001) and 97% more likely in severely obese patients (95% CI, 1.30-.296; P = .001) then patients with a normal BMI. Only obese patients were at a significantly higher risk of severe ARDS than normal BMI patients (RR, 1.57; 95% CI, 1.11-2.23; P = .01).

Investigators concluded their assessment showed associations between worsened BMI and sepsis-related ventilator use and duration, as well as risk of ARDS in such patients—highlighting an area of acute event burden that obese individuals may face.

“Obese and severely obese patients admitted in ICU with sepsis had increased duration of ventilator use,” they wrote. “There is also a significant relationship between BMI and the risk of developing ARDS.”

The study, “Influence of Body Mass Index on the Duration of Ventilator Use and Its Association with Acute Respiratory Distress Syndrome,” was published online by ATS.