Body Mass Index and Intensive Care Unit Outcomes in African American Patients

Abstract

Obesity IntroductIonObesity defined by BMI ≥ 30 kg/ m 2 has increased in the United States in the last three decades. More than one-third of US adults were obese in 2012 1,2 and obesity is projected to rise to more than 50% by the year 2030. 3 While the overall prevalence of obesity has increased, significant racial/ ethnic disparities continue to exist; with highest prevalence found among non-Hispanic Black (47.8%) vs nonHispanic White (32.6%) adults. 1,4 As the prevalence of obesity increases, the numbers of critically ill obese patients will continue to increase making this situation important to examine.Obesity is associated with derangement of cardiovascular and metabolic function 5 leading to increase in comorbid illnesses 6 that can complicate ICU care. Obesity affects respiratory physiology 7,8 leading to decreased chest wall and lung compliance making mechanical ventilator management difficult. In addition to metabolism and clearance of medications, physical factors of obesity, such as a poor anatomical land marks, makes intubation and vascular access placement difficult, 9 adding challenges to ICU management.Despite these challenges of obesity in the ICU and obesity's association with increased all-cause mortality, 10 the effect of obesity on critical illness is less understood. Few prior studies have assessed the effect of BMI on medical ICU outcomes in African American (AA) patients. 11,12The results from previous studies and three meta-analyses addressing this topic [13][14][15] have mostly been from mixed medical-surgical ICU populations 13-18 and did not include a subgroup analysis by race or the type of ICU (trauma, surgical vs medical) to which patients were admitted. In studies including only patients admitted to medical ICUs (MICU), some lacked appropriate non-obese comparison, 19,20 others used a different definition of obesity 21 or included only limited BMI groups. 11Our study aimed to describe the relationship between a wide range of Purpose: We sought to determine whether body mass index (BMI) is associated with worse intensive care unit (ICU) outcomes among Black patients. Methods:Patients admitted to the medical ICU during 2012 were categorized into six BMI groups based on the World Health Organization criteria. ICU mortality, ICU and hospital length of stay (LOS), need for and duration of mechanical ventilation and organ failure rate were assessed.Results: A total of 605 patients with mean age 58.9 ± 16.0 years were studied. Compared with those with normal BMI, obese patients had significant higher rates of hypertension, diabetes mellitus and obstructive sleep apnea diagnoses (P<.001 for all). A total of 100 (16.5%) patients died during their ICU stay. Obesity was not associated with increased odds of ICU mortality (OR=.58; 95% CI, .16-2.20). Moreover, improved survival was observed for class II obese patients (OR, .031; 95% CI, .001-.863). There were no differences in the need for and duration of mechanical ventilation between the BMI groups. However, ICU and hospital LOS were signifi...

Is body mass index associated with outcomes of mechanically ventilated adult patients in intensive critical units? A systematic review and meta-analysis

“…A total of 199,421 subjects participated in the 23 studies, which consisted of 14 prospective [ 8 , 13 , 18 – 29 ] and 9 retrospective cohort studies [ 9 – 12 , 30 – 35 ]. Fourteen studies were from North America [ 9 , 10 , 12 , 13 , 19 , 20 , 21 , 25 , 27 , 28 , 30 , 32 – 34 ], one from South America [ 31 ], five from Europe [ 8 , 18 , 22 , 23 , 24 , 29 ], and two from Australia [ 26 , 35 ]. In seven studies [ 8 , 9 , 18 , 19 , 22 , 31 , 32 ], BMIs was classified only into obese versus non-obese ( Table 1 ).…”

Dose‐Response Meta‐Analysis of the Impact of Body Mass Index on Mortality in the Intensive Care Unit

“…We assessed nonlinear association in 24 studies between BMI and the risk of mortality in the ICU. 13,14,16,19,27,28,[31][32][33]35,36,38,39,[40][41][42][43][44][45][46][47][48]49,53 Results showed a decrease in risk of mortality with an increase of BMI levels up to ≈35 kg/m 2 (P nonlinearity < .001). However, the risk of mortality increased in BMIs higher than 35 kg/m 2 (P nonlinearity < .001) ( Figure 3).…”

“…Studies were conducted in different countries. Most studies were in the United States, 14,16,[27][28][29][30][31][32][33][34]35 whereas the remaining were from the United Kingdom, 36 France, 19,37 Korea, 38 Canada, Germany, [39][40][41] Italy, 42 Austria, 13,[43][44][45] the Netherlands, 46 Saudi Arabia, 47 Brazil, 48 and Japan. 49 Follow-up period was from 1 month to 11 years.…”

Impact of Body Mass Index on the Mortality of Critically Ill Patients Admitted to the Intensive Care Unit: An Observational Study

“…Still, obesity was signi cantly associated with longer length of stay and increased comorbid illness [28]. Recent studies are intended to evaluate the issue in larger study populations, among different subgroups, and according to the etiology context [26,29,30]. A recent dose-response meta-analysis regarding the effect of BMI on the mortality of ICU-admitted patients showed that for each unit of increase in BMI (kg/m2), a 0.6% decrease in mortality rate is expected [31].…”

“…Likewise, a study conducted by Lewis et al, on the patients admitted to an adult medical ICU with a more than 24 hours stay, presented that the overweight and obesity were not related to ICU mortality. Still, obesity was signi cantly associated with longer length of stay and increased comorbid illness [28]. Recent studies are intended to evaluate the issue in larger study populations, among different subgroups, and according to the etiology context [26,29,30].…”