An observational study of adult admissions to a medical ICU due to adverse drug events.

BACKGROUND: The objectives of the study were to estimate the incidence of intensive care unit (ICU) admissions due to adverse drug events (ADEs), to assess preventability, severity and costs of the corresponding ADE and to determine the leading causes of preventable ADEs.

METHODS: An observational study was conducted in a medical ICU of a teaching hospital from February 2013 to February 2014.

RESULTS: A total of 743 consecutive admissions were included, and they involved 701 different patients. The included admissions were categorized into three groups (admissions due to preventable ADE, admissions due to unpreventable ADE and the control group). Among the 743 ICU admissions included during the study period, 173 (23.3 %) were due to ADE, with 102 (13.7 %) related to preventable ADE and 71 (9.6 %) to unpreventable ADE, yielding a preventability rate of ADE of 0.59 (102/173). Admissions due to unpreventable ADE concerned patients with more comorbidities, a greater number of drugs and higher Simplified Acute Physiology Score II than admissions due to preventable ADE and the control group admissions (n = 570). Hospital mortality rates, corresponding costs and length of stay were all similar in the preventable ADE and control groups, whereas they were always significantly higher in the unpreventable ADE group. ICU mortality, length of stay and the corresponding costs were similar in the three groups. Non-compliance was the principal leading cause of preventable ADE (n = 31/102). The 102 preventable ADE-related admissions accounted for a total of 528 days of hospitalization in the ICU, requiring a mean of 1.4 ICU beds per day over the one-year period, with an associated total cost amounting to 747,651 €.

CONCLUSIONS: ADE was a major cause of admission in the studied ICU, and in 59 % of the cases, ADEs were preventable. The reported burden of ICU admissions due to ADE advocates for further investigations to explore how the rate of such admissions could be decreased.