Prevalence and Risk Factors of Potential Drug Interactions in Hospitalized Cardiovascular Patients Using Three Knowledge Bases

Background: Drug interactions continue to be an important cause of adverse effects, especially with cardiovascular drugs.

Objective: This cross-sectional observational study aimed to recognize the frequency of potential drug-drug interactions (pDDIs) using three electronic knowledge bases (KBs); Lexicomp®, Micromedex®, and the free Drugs.com®, compare the inclusion and gradings of pDDIs in these three KBs and to identify associated risk factors.

Methods: Medication orders of 125 patients in the cardiovascular department and its intensive care unit (ICU) of Assiut University Hospitals, Egypt were screened for pDDIs.

Results: About 88.8% of the patients were prescribed five or more drugs. A sum of 1206 pDDIs was found which comprised of 245 different interacting pairs. Overall, 96.8% of the patients had at least one pDDI. Moderate risk pDDIs represented the most frequent risk level at 72.24%. Statistical analysis of data by multivariate regression has shown that the number of drugs prescribed could significantly predict the number of pDDIs (p<0.001). This was confirmed by bootstrapped Spearman's correlation (rs(123)=0.808; bias-corrected and accelerated [BCa] 95% confidence interval, 0.719–0.873; p<0.001). Drugs.com® alerted the largest number of pDDIs. Both Drugs.com® and Lexicomp® have shown that most prevalent pDDIs were moderate and that contraindicated were the least, while the major grading was the largest in Micromedex®.

Conclusion: A high prevalence of pDDIs was detected, and polypharmacy was a major risk factor. Physicians need to determine the most relevant approach to check for pDDIs while balancing between excessive alerting and overriding of interacting drug pairs. the Integration of medication review guidelines and computerized alert systems should be considered.