Purpose: Multimorbid patients often take many different medicaments at the same time. Those can have clinically relevant interactions or can be overdosed, due to ne-glected interactions or organ insufficiency. Especially in patients with renal insuffi-ciency this can happen very easily. The aim of this study is to investigate whether mul-timorbid patients suffer from more medication errors than non-multimorbid patients.
Methods: Anonymous patient data of 2014 from the University Hospital of Zurich were used to perform a retrospective data analysis. There are different kinds of medication interactions. First, there are drug-drug-interactions, which happen when two contrain-dicated medicaments are falsely given together and can lead to an adverse drug reac-tion. Other interactions covered in this study are drug-disease interactions and dose adjustment errors, where a drug has not been dose adjusted correctly in a patient with renal impairment. These interactions were identified for in the data and along their ef-fects on patients’ mortality and morbidity.
Results: We could show that the more diagnoses a patient has, the more likely it is that the patient has a medication error. The mortality of patients who had medication errors was 5.1% whereas the mortality of patients without medication error was at 2.3% (p<10-12). It was also shown that patients with medication errors stayed longer in the hospital (15.6 days) versus the patients without medication errors (6.5 days) (p<10-15).
Conclusions: Medication errors are a big problem in today’s hospitals. Due to in-creased life expectancy multimorbidity is increasing and thus also medication lists are getting longer. In the environment of a hospital drugs are often falsely prescribed in a contraindicated combination or not dose adjusted for renal impairment. Those have a clinically relevant impact on the patient who is more likely to have an exaggerated course of disease leading to a higher mortality. The average length of hospital stay is also getting longer which implies that the medication interactions have an impact on patients’ morbidity and thus success of treatment.