Introduction

The prevalence of obesity presents a burden for Australian health care. The aim of this study was to determine whether obese hospital inpatients have worse outcomes.

Methods

Data were recorded from all adult patients admitted to two Australian tertiary hospitals between February 2008 and February 2012. Outcomes included length of stay (LOS), ICU admission, ICU LOS, mortality and re-admission within 28 days of discharge. We adjusted for patient age, gender, SEIFA index, primary diagnosis, emergency or elective nature of admission and Charlson index, an index of complexity of acute illness.

Results

Of 120,872 admitted patients, 2.3% were identified as significantly obese by nursing staff (ie >120 kg) or coding staff (ie obesity associated comorbidity). These obese patients were younger (54.4 ± 15.4 cf 56.7 ± 21.1; p < 0.001) but had a higher Charlson index (1.3 ± 2.0 cf 0.8 ± 1.7; p < 0.001) and were more likely to be admitted electively (30.0% cf 20.2%; p < 0.001). Overall, admissions in obese, compared to non-obese, patients were: more frequent (2.45 ± 2.58 times cf 1.64  ± 1.51 times; p < 0.001); longer (8.7 ± 14.9 days cf 5.2 ± 9.0 days; p < 0.001);  more likely to be admitted to ICU (17.2% cf 7.6%; p < 0.001) and be readmitted to hospital (8.1% cf 5.4%; p < 0.001). In-hospital mortality was not increased in the obese group.  During elective admissions, obesity had less effect on length of stay (10% increase; p = 0.011) and ICU admission rate (51% increase; p < 0.001) than in emergency admissions.

Conclusions

Following emergency or elective hospital admission, obese patients consume more resources than non-obese patients. The reasons for these poorer outcomes require further study and we must develop and trial strategies to improve them.