OBJECTIVES: It is a globally accepted premise that adverse events are undesirable consequences of overuse. Several studies have estimated the economic impact of inappropriate use of hospitalization. This paper aims to analyze the differences between AEs associated with the inappropriateness of hospital admission (IHA) vs AEs not associated with this type of overuse.

METHODS: A cross-sectional study of all hospitalized patients in a high-complexity hospital was performed. The measurement of IHA was made with the Appropriateness Evaluation Protocol, and the Harvard Medical Practice Study methodology was used to measure AEs on the same sample. The economic cost was estimated from the days of hospital stay added by the AEs, considering the average cost of each day of hospitalization for each service at the time of the study. The Mann-Whitney U test was used to compare the differences between both types of AEs.

RESULTS: 558 patients were studied. A total of 487 patients had an appropriate admission (87.3%; 52 patients with AEs [10.7%]), and 71 had an IHA (12.7%; 11 patients with ≥1 AE [15.5%]). A total of 80 AEs were detected in the whole sample (61 with appropriate admission; 19 with IHA). AEs produced an additional extra cost of €385,238.3. AEs occurring after IHA incurred higher costs resulting from additional days of ICU stay (€104,475.9 in total in ICU stays, compared to €93,338.5 for AE developed after appropriate admissions; p=0.039).

CONCLUSIONS: The AEs produced after an IHA have a more significant economic impact derived from a greater association with the need for ICU derived from them. Mitigating the IHA would be a strategy that would be effective reducing the economic impact of AEs.