Analysis of Adverse Drug Reaction Risk in Elderly Patients Using the Japanese Adverse Drug Event Report (JADER) Database

In general, the risk of adverse drug reactions (ADRs) is higher in elderly patients than in younger patients. In this study, we performed a comprehensive assessment of the risks of possible drug-ADR combinations in elderly patients using the Japanese Adverse Drug Event Report (JADER) database of the Pharmaceutical and Medical Devices Agency (PMDA, Japan) using the reporting odds ratio (ROR) as an index. Data recorded from April 2004 to September 2015 in the JADER database were downloaded from the PMDA web site. The patients were classified into younger (<= 69 years old) and elderly (>= 70 years old) groups. The ROR and 95% confidence interval (CI) were calculated for all combinations of drugs and ADRs for which there were three or more reports in the database, focusing particularly on the combinations where more than 100 cases had been reported in elderly and younger patients. The most frequently reported drug-ADR combination was methotrexate with interstitial lung disease (646 cases). The combination with the highest ROR was methotrexate with lymphoproliferative disorder (ROR: 484.6, 95% CI: 334.1-702.9). In total, 27 drug-ADR combinations were found to have high risk in elderly patients. In conclusion, the findings of this comprehensive assessment of drug-ADR combinations using the JADER database will be valuable for updating the ADR risks for elderly patients in clinical setting.