The role of physical activity and body mass index in the health care use of adults with asthma

Background: Health care use in patients with asthma is affected by many factors, including sex and ethnicity. The role of physical activity (PA) and body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) in this relationship is unknown. Objective: To determine the role of PA and BMI in the health care use of patients with asthma. Methods: A sample of adults with asthma (n=6,835) and without asthma (n=78,051) from cycle 3.1 of the Canadian Community Health Survey was identified. Health care use was self-reported as overnight hospital stays (yes or no), length of overnight hospital stay (<4 or >= 4 nights), and physician consultations (<3 or >= 3). Self-reported physical activities were used to derive total energy expenditure and to classify participants as active (>3.0 kcal/kg of body weight per day), moderately active (1.5-3.0 kcal/kg of body weight per day), and inactive (<1.5 kcal/kg of body weight per day). The BMI was categorized as normal weight (18.5-24.9), overweight (25.0-29.9), and obese (30.0-59.9). Results: Adjusted logistic regression models revealed that patients with asthma were more likely to have an overnight hospital stay (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.95-2.60), 4 or more overnight hospital stays (OR, 1.48; 95% CI, 1.12-1.96), and 3 or more physician consultations (OR, 2.43; 95% CI, 2.18-2.71) compared with patients without asthma (OR, 1.00). Inactive patients with asthma were more likely to have an overnight hospital stay (OR, 1.68; 95% CI, 1.31-2.16) and 3 or more physician consultations (OR, 1.23; 95% CI, 1.04-1.46) than active patients with asthma (OR, 1.00). Inactive/obese patients with asthma were 2.35 (95% Cl, 1.69-3.27) times more likely to have an overnight hospital stay and 2.76 (95% Cl, 2.11-3.60) times more likely to have 3 or more physician consultations than active/normal weight patients with asthma (OR, 1.00). Conclusions: Higher PA levels are associated with lower health care use in individuals with and without asthma. In those with asthma, PA was a more important factor in overnight hospital stays than BMI, whereas both BMI and PA were important determinants of physician consultations. Ann Allergy Asthma Immunol. 2009; 102:462-468.