The incidence and cost of adverse events in Victorian hospitals 2003-2004

Objectives: To determine the incidence of adverse events in patients admitted in the year 2003-04 to selected Victorian hospitals; to identify the main hospital-acquired diagnoses; and to estimate the cost of these complications to the Victorian and Australian health system. Design: The patient-level costing dataset for major Victorian public hospitals, 1 July 2003 - 30 June 2004, was analysed for adverse events by identifying C-prefixed diagnosis codes denoting complications, preventable or otherwise, arising during the course of hospital treatment. The in-hospital cost of adverse events was estimated using linear regression modelling, adjusting for age and comorbidity. Main outcome measures: Cost of each patient admission ("admitted episode"), length of stay and mortality. Results: During the designated timeframe, 979834 admitted episodes were in the sample, of which 67 435 (6.88%) had at least one adverse event. Patients with adverse events stayed about 10 days longer and had over seven times the risk of in-hospital death than those without complications. After adjusting for age and comorbidity, the presence of an adverse event adds $6826 to the cost of each admitted episode. The total cost of adverse events in this dataset in 2003-04 was $460.311 million, representing 15.7% of the total expenditure on direct hospital costs, or an additional 18.6% of the total inpatient hospital budget. Conclusion: Adverse events are associated with significant costs. Administrative datasets are a cost-effective source of information that can be used for a range of clinical governance activities to prevent adverse events.