Table 1  Main observational studies reporting epidemiology and outcomes in obese patients with acute respiratory distress syndrome (ARDS)
|  | O’Brien et al. (2004) [18] | O’Brien et al. (2006) [9] | Morris et al. (2007) [19] | Gong et al. (2010) [6] | Stapleton et al. (2010) [20] | Anzueto et al. (2011) [7] | Soto et al. (2012) [21] | De Jong et al. (2018) [22] |
|---|---|---|---|---|---|---|---|---|
Type of study | Prospective multicenter | Retrospective multicenter | Prospective multicenter | Prospective multicenter | Retrospective multicenter | Prospective multicenter | Retrospective multicenter | Retrospective single center |
Country | USA | USA | USA | USA | USA | International | USA | France |
Purpose | To examine the association between excess BMI and outcome in mechanically ventilated ARDS patients | To describe the influence of admission BMI on outcome of critical illness in mechanically ventilated ARDS patients | To clarify the relationship between BMI and ICU outcomes, particularly in patients with ARDS | To determine if BMI and obesity are associated with development of ARDS and mortality in ARDS | To assess if cytokine response might be attenuated in patients who are obese and critically ill or if obesity might modify the relationship between plasma cytokines and clinical outcomes in ARDS | To describe the influence of BMI on clinical outcomes in a large cohort of mechanically ventilated patients | To evaluate whether BMI was associated with AKI in the ARDS patients | To evaluate the relationship between 90-day mortality and driving pressure in ARDS patients according to obesity status |
Main endpoints | Mortality at 28 days | Hospital mortality | Mortality, hospital LOS, ICU LOS | Development of ARDS and all-cause 60-day mortality | Plasma cytokine levels | Incidence of ARDS, ICU and hospital mortality | Mortality at 60 days after ARDS | Mortality at day 90 |
Included patients | 902 mechanically ventilated patients with ARDS | 1488 mechanically ventilated adults with ARDS included in the Project IMPACT database | 825 mechanically ventilated patients with ARDS | 1795 patients | 1409 mechanically ventilated patients with ARDS | 4968 adult patients who received mechanical ventilation for more than 12 h | 751 patients with ARDS | 362 mechanically ventilated ARDS patients |
Period of inclusion | 1996–1999 | 1995–2001 | 1999–2000 | 1999–2007 | 1996–2002 | 2004 | 1999–2010 | 2009–2017 |
Main result | After risk adjustment, excess BMI was not associated with death | BMI was independently associated with hospital mortality (p < 0.0001) when modeled as a continuous variable. The adjusted odds were highest for the lowest BMIs and then declined to a minimum between 35 and 40 kg/m2 | No ICU mortality difference. Severely obese patients had longer hospital LOS than normal weight patients | BMI was associated with ARDS on multivariable analysis. Among patients with ARDS, increasing BMI was associated with increased LOS (p = 0.007) but not with mortality | Obese patients with ALI had lower levels of several pro- inflammatory cytokines. Unadjusted 90-day mortality was highest in patients who were underweight (45.9%) and lowest in patients who were obese (27.6%) (p < 0.05). After adjustment, BMI was not associated with mortality | After adjustment, the BMI was significantly associated with the development of ARDS. No differences in outcomes (duration of mechanical ventilation, LOS or ICU/hospital mortality | The prevalence of AKI increased significantly with increasing weight. On multivariable analysis, AKI was associated with increased ARDS mortality whereas BMI was associated with decreased mortality | Contrary to non-obese ARDS patients, driving pressure was not associated with mortality in obese ARDS patients. Mortality rate did not differ between obese and non-obese patients, before or after multivariable analysis |