Categorisation of Pharmaceutical Adverse Events Using the Japanese Adverse Drug Event Report Database: Characteristic Adverse Drug Events of the Elderly Treated with Polypharmacy.

BACKGROUND

Pharmacokinetics and pharmacodynamics of drugs in elderly individuals differ from those in younger adults; thus, adverse drug events (ADEs) are common in older patients with polypharmacy because co-existing comorbidities elevate the risk of ADEs occurring. However, ADEs have not yet been characterised based on the elderly patients of Japanese origin and polypharmacy.

OBJECTIVE

The 100 most commonly reported ADEs were grouped into four classes (Class 1-Class 4) based on elderly patients with polypharmacy.

PATIENTS AND METHODS

In this study, logistic regression analysis was performed using cases recorded in the Japanese Adverse Drug Event Report (JADER) database.

RESULTS

ADEs in elderly patients treated with polypharmacy-in whom the risk of electrolyte abnormalities, renal and respiratory disorders, and coagulopathy was high-were categorised as 'Class 1 [E(+), P(+)]', while ADEs in elderly patients not treated with polypharmacy-in whom the risk of delirium and fall was high-were categorised as 'Class 2 [E(+), P(-)]'. When there was no association with being elderly, ADEs associated with polypharmacy that carried a high risk of myelosuppression and infection were categorised as 'Class 3 [E(-), P(+)]', and allergic ADEs that were not affected by being elderly or polypharmacy, were categorised as 'Class 4 [E(-), P(-)]'. Class 1 events as well as Class 3 ADEs occurred more frequently in females than in males, whereas Class 3 ADEs (deep vein thrombosis and pulmonary embolism) occurred more frequently in males.

CONCLUSIONS

Class 1 and Class 2 ADEs should be investigated in analyses that focus on individual drugs.