Obesity, hospital services use and costs.

OBJECTIVE: To quantify the association between obesity and somatic hospital costs and number of overall somatic hospital contacts--number of inpatient admissions, number of outpatient visits, and number of emergency department visits--based on anthropometric measurements of waist circumference (WC) and information from The National Patient Registry and The Danish Case-Mix System (DRG). PARTICIPANTS: The study population consisted of two sub-samples from the Inter99 study at Research Centre for Prevention and Health in 1999-2001. One sub-sample used WC as an indicator for obesity (n = 5,151), whereas the other used BMI as an indicator for obesity (n = 4,048). Using WC, obesity was defined as WC > 102 cm for men and > 88 cm for women. Normal weight was defined as circumference < 94 cm for men and < 80 cm for women. Using BMI, obesity was defined as BMI > 30 kg/m2, whereas individuals with BMI = 18.5-24.9 kg/m2 were defined as normal weight. Individuals with BMI < 18.5 kg/m2 were excluded from both sub-samples.
DESIGN: We undertook a 3-year retrospective study of the relationship between obesity and use of hospital resources. Data on hospital contacts and costs were obtained from The National Patient Registry and DRG. Analyses were performed using two-part models and Poisson regression. Outcome variables were costs and hospital contacts.
RESULTS: This study has demonstrated that obese individuals have a greater use of hospital services and greater hospital costs compared with normal weight individuals. When using WC as an indicator for obesity, mean hospital costs were 33.8% greater among obese women and 45.3% greater among obese men in a 3-year period but the differences were not significant. When using BMI to measure obesity, obese men had significantly greater costs (57.5%) than normal weight men. Furthermore, obese men and women (indicated by WC) had an increased number of hospital contacts compared with normal weight individuals (rate ratio 1.32, 95% CI 1.21-1.43 for men and 1.20, 95% CI 1.11-1.28 for women) including inpatient admissions, outpatient visits, and emergency department visits. The same trends were seen when obesity was indicated by BMI.