Body mass index is associated with the development of acute respiratory distress syndrome

Abstract

Background: The relationship between body mass index (BMI) and development of acute respiratory distress syndrome (ARDS) is unknown. Methods: A cohort study of critically ill patients at risk for ARDS was carried out. BMI was calculated from admission height and weight. Patients were screened daily for AECC (American European Consensus Committee)-defined ARDS and 60-day ARDS mortality. Results: Of 1795 patients, 83 (5%) patients were underweight (BMI ,18.5 kg/m 2 ), 627 (35%) normal (BMI 18.5-24.9), 605 (34%) overweight (BMI 25-29.9), 364 (20%) obese (BMI 30-39.9) and 116 (6%) severely obese (BMI >40). Increasing weight was associated with younger age (p,0.001), diabetes (p,0.0001), higher blood glucose (p,0.0001), lower prevalence of direct pulmonary injury (p,0.0001) and later development of ARDS (p = 0.01). BMI was associated with ARDS on multivariate analysis (OR adj 1.24 per SD increase; 95% CI 1.11 to 1.39). Similarly, obesity was associated with ARDS compared with normal weight (OR adj 1.66; 95% CI 1.21 to 2.28 for obese; OR adj 1.78; 95% CI 1.12 to 2.92 for severely obese). Exploratory analysis in a subgroup of intubated patients without ARDS on admission (n = 1045) found that obese patients received higher peak (p,0.0001) and positive end-expiratory pressures (p,0.0001) than non-obese patients. Among patients with ARDS, increasing BMI was associated with increased length of stay (p = 0.007) but not with mortality (OR adj 0.89 per SD increase; 95% CI 0.71 to 1.12). Conclusion: BMI was associated with increased risk of ARDS in a weight-dependent manner and with increased length of stay, but not with mortality. Additional studies are needed to determine whether differences in initial ventilator settings may contribute to ARDS development in the obese.

Predictors of Outcome in 216 Subjects With ARDS Treated With Inhaled Epoprostenol

“…Previous studies have shown that obesity is associated with the development of ARDS. 31,32 However, a recent French study found the use of prone positioning to be safe in obese subjects, and prone positioning improved oxygenation more in obese subjects with ARDS than in non-obese subjects. 33 Our study has several important limitations.…”

Obesity and Mortality Risk in Critically Ill Children

“…Some investigators, although not all, believe that obese children have higher morbidity and mortality. [2][3][4] In adults, higher BMI is associated with the development of acute respiratory distress syndrome (ARDS) 5 ; for those developing ARDS, increasing BMI was associated with prolonged stay. However, increased BMI was not associated with increased mortality.…”

Exhaled Breath Condensate Nitrate Levels are Inversely Associated with the Body Mass Index of Patients without Respiratory Disease

“…Volume 5 that is not matched with a greater mortality [15,16]. As mentioned, this unexplained finding has been called the obesity-ARDS paradox [18,19].…”

“…The obesity paradox usually refers to the unexplained decreased overall mortality and decreased mortality from cardiovascular events in otherwise healthy mildly obese patients compared to normal weight patients [7,10,11]. Repeated studies report a decreased incidence and/or reduced mortality from the acute respiratory distress syndrome (ARDS) [12][13][14][15] in obese patients compared to normal weight individuals, although a few conflicting findings exist [15,16]. In addition, obesity has been associated with a delayed ARDS onset during an ICU stay [15] and lower plasma inflammatory markers during ARDS development [17].…”

“…Repeated studies report a decreased incidence and/or reduced mortality from the acute respiratory distress syndrome (ARDS) [12][13][14][15] in obese patients compared to normal weight individuals, although a few conflicting findings exist [15,16]. In addition, obesity has been associated with a delayed ARDS onset during an ICU stay [15] and lower plasma inflammatory markers during ARDS development [17]. We have labeled this unexplained phenomenon as the "obesity-ARDS paradox" [18,19].…”