Body mass index and risk of hospitalization among adults presenting with asthma exacerbation to the emergency department.

Abstract

Studies have linked obesity to incident asthma and worse chronic severity/control. However, the relationship between obesity and acute asthma morbidity remains unclear. To determine whether obese adults presenting to the emergency department (ED) with asthma exacerbation are at higher risk of hospitalization compared with normal-weight adults. Multicenter chart review study of 48 EDs across 23 U.S. states. We identified ED patients aged 18 to 54 years with asthma exacerbation during 2011 to 2012. Primary outcome was hospitalization. The analytic cohort comprised 1,227 patients. Of these, 323 patients (27%) were overweight (body mass index [BMI], 25-29.9 kg/m(2)), and 607 (50%) were obese (BMI ≥ 30 kg/m(2)). Among the 607 obese patients, 364 patients (60%) were severely obese (BMI ≥ 35 kg/m(2)). Several markers of chronic severity/control of asthma and acute severity did not differ across BMI groups. By contrast, compared with normal-weight patients, the risk of hospitalization was higher in patients who were overweight (11 vs. 18%; odds ratio [OR], 1.68; 95% confidence interval [CI], 1.05-2.68; P = 0.03) or obese (11 vs. 23%; OR, 2.30; 95% CI, 1.53-3.49; P < 0.001). In the adjusted analysis with multiple imputation, the association lost statistical significance in overweight patients (OR, 1.56; 95% CI, 0.90-2.71; P = 0.11) but persisted in obese patients (OR, 1.69; 95% CI, 1.02-2.81; P = 0.04). The latter finding was driven by an even higher risk of hospitalization in severely obese patients (OR, 1.95; 95% CI, 1.13-3.34; P = 0.02). In this multicenter study of ED patients with asthma exacerbation, we found that obese adults were at a higher risk of hospitalization compared with normal-weight adults.