Purpose: The excess health care costs caused by obesity are a concern in many countries, yet little is known about the additional resources required to treat obese patients in hospitals. Our objective is to estimate differences in hospital resource use, measured by length of stay, between obese and non-obese patients, conditioning on a range of patient and hospital characteristics.
Methods: Our data consist of administrative patient-level hospital data for 122 public hospitals over the financial year 2005/06 consisting of inpatient episodes (461,563) for patients above 6 years of age and with a stay of one night or more. We use quantile regression analysis to generate 19 estimates of the difference between obese and non-obese patients across the whole range of length of stay, from very short to very long staying patients. Separate estimates for 17 hospital specialties and for medically and surgically treated patients are generated.
Results: There are significant differences in average length of stay for almost all specialties. For some, differences are less than one day, but for others, obese patients stay up to four days longer. For a number of specialties, obese patients have significantly shorter length of stay. Overall, medically managed obese patients stay longer, whereas surgically treated patients stay shorter than non-obese patients. Differences tend to increase with length of stay.
Conclusions: Differences in length of stay may arise because obese patients are medically more complex. The observed shorter stays for obese patients in some specialties may result from their observed greater likelihood of being transferred to another hospital.
Candidate for the Lee B. Lusted Student Prize Competition