Risk factors for adverse drug events
The purpose of this study was to identify inpatient risk factors for adverse drug events (ADEs). This study of adult patients was performed at large tertiary-care teaching hospital in Utah. Conditional logistic regression was used to analyze all ADEs by therapeutic class of drugs and severity over a 10-year period. This study was unique in that each case patient was matched with up to 16 controls. Odds ratios for numerous risk factors were identified for a total of 4376 ADEs and were found to vary depending on therapeutic classification. The risk factors for the different classifications were grouped by patient characteristics, drug administration and patient type.
When compared to previous studies on ADEs, the results were surprising and raised some new issues. There was a consistent association between female gender and ADEs. Unlike previous studies, older age was not associated with a higher risk of ADE for any drug class. Low body weight and low creatinine clearance were associated with a significant risk for ADEs due to cardiovascular drugs. The number of patient comorbidities was associated with increased risk of all ADEs. However, after accounting for the number of comorbidities, the number of concomitant drugs was not a risk factor, with the exception of anticoagulants. In patients on anticoagulants, the number of concomitant drugs was a risk factor. Compared with low dose, both moderate and high medication dosages were risk factors for ADEs. Unlike previous studies, parenteral administration was a significant risk factor. The highest risk factors in the entire study were patient-controlled analgesia and epidural routes. When looking at patient types, the diagnosis-related group with the highest risk of ADEs was women with cesarean sections and other gynecologic surgeries, mostly related to narcotic analgesics.
The conclusion of the study was that there were high-risk drugs for ADEs and high-risk patients for ADEs. The high-risk drugs were identified by looking at dosage, administration route and number of concomitant drugs. The high-risk patients were identified based on gender, age, weight, creatinine clearance and number of comorbidities.
There were several pertinent findings in this study. Patient-controlled analgesia and epidural routes were the highest risk factors for ADEs. These administration protocols need to be studied and reviewed, for patient safety. The finding that women were at increased risk of ADEs and that older people were not at increased risk of ADEs was new and unique information which will fuel future research.