[Assessing the economic impact of adverse events in Spanish hospitals by using administrative data]

To evaluate the incidence and costs of adverse events registered in an administrative dataset in Spanish hospitals from 2008 to 2010.

A retrospective study was carried out that estimated the incremental cost per episode, depending on the presence of adverse events. Costs were obtained from the database of the Spanish Network of Hospital Costs. This database contains data from 12 hospitals that have costs per patient records based on activities and clinical records. Adverse events were identified through the Patient Safety Indicators (validated in the Spanish Health System) created by the Agency for Healthcare Research and Quality together with indicators of the EuroDRG European project.

This study included 245,320 episodes with a total cost of 1,308,791,871€. Approximately 17,000 patients (6.8%) experienced an adverse event, representing 16.2% of the total cost. Adverse events, adjusted by diagnosis-related groups, added a mean incremental cost of between €5,260 and €11,905. Six of the 10 adverse events with the highest incremental cost were related to surgical interventions. The total incremental cost of adverse events was € 88,268,906, amounting to an additional 6.7% of total health expenditure.

Assessment of the impact of adverse events revealed that these episodes represent significant costs that could be reduced by improving the quality and safety of the Spanish Health System.