Background: Negative outcomes of medications (NOMs) are a major public health problem that impact on patients' quality of life. As many NOMs are avoidable, it is necessary to determine their causes in each health setting in order to plan preventive strategies.
Objective: The aims of this study were to assess the frequency, type, severity, and preventability of NOMs that result in emergency department visits, to identify the main medications involved, and to determine factors associated with their development in a general hospital in Spain.
Setting: Emergency department of a 650-bed university tertiary hospital.
Methods: Descriptive, cross-sectional study. On each study day, a pharmacist administered a questionnaire to one in every three patients awaiting consultation. Information was also obtained from the emergency medical records. Emergency department visits were identified as NOMs on the basis of assessment by a pharmacist and a physician. A second pharmacist and physician reassessed the same cases. Discrepancies were adjudicated by an external team of two pharmacists and a physician.
Main outcome measures: Number of NOMs detected, severity and preventability of the NOMs detected, medications involved in these NOMs, and factors associated with NOMs.
Results: A NOM was detected in 221 of 588 patients analyzed (37.6 %). In relation to NOM severity, 59.3 % were mild, 34.4 % were moderate and 6.3 % were severe. One hundred and fifty-seven of the 221 NOMs (71 %) were considered preventable. Drugs most frequently involved in NOMs were nervous system agents (22.1 %), musculo-skeletal system agents (19.1 %), and anti-infective agents for systemic use (17.6 %). Mean number of drugs taken was the only factor associated with NOMs.
Conclusion: The high number of NOMs detected indicates that closer pharmacotherapy follow up is needed to avoid such events in our setting.