Category: Professional Posters
Purpose: As older patients are frequently subjected to polypharmacy (PP), adverse events caused by potentially inappropriate medications (PIMs) and drug-drug interactions (DDIs) have been frequently reported in the literature. PP, PIMs, and DDIs may cause increased risk of falls, frailty, adverse events, and reduced efficacy of certain chemotherapy. Despite these issues, studies on the prevalence of PP, PIMs, and DDIs in older patients with cancer receiving chemotherapy have been conducted in relatively small samples, and nationwide population-based studies are limited. Therefore, we aimed to investigate the prevalence of PP and PIMs during chemotherapy in older Korean patients with cancer.
Methods: We used the 2016 National Adult Patient Sample database obtained from the Korean Health Insurance Review and Assessment Service (HIRA) database, comprising 1,327,455 patients. From this database, we selected patients diagnosed with cancer, who were prescribed an anticancer drug during 2016. Anticancer drugs were defined as antineoplastic agents (Anatomical Therapeutic Chemical code (ATC code) L01) and endocrine therapy (ATC code L02). PP was defined as the concurrent use of five or more chronic medications. PIMs were assessed according to the 2019 American Geriatrics Society (AGS) Beers Criteria® for potentially inappropriate medication use in older adults. PIMs that were dependent on their diagnosis or condition were excluded. We only counted once when the same type of PIM was repeated. Prevalence of potentially clinically important DDIs that should be avoided in older adults as described in the 2019 AGS Beers Criteria® was also evaluated.
Results: In total, 21,956 patients (1.7%) were diagnosed with cancer and prescribed anticancer drugs. The mean age was 74.2 years, and 62.6% of the patients were men. Among them, prevalence of PP was 69.1% and 26.8% of patients were prescribed more than 10 medications.
A total of 51,531 cases in 18,860 subjects (85.9%) were prescribed at least one PIM independent of their diagnosis or condition, and 2,681 patients (12.2%) had five or more types of PIMs. PIMs associated with strong anticholinergic effects were prescribed in 64.8% of patients, with first- generation antihistamines being the most commonly used (59.1%), followed by antispasmodics (9.2%), anticholinergic antidepressants (7.8%), and muscle relaxants (3.3%). The most commonly prescribed medication class other than strong anticholinergics was megestrol (26.2%); these were followed by benzodiazepines (25.4 %), meperidine (20.3%), metoclopramide (19.8%), and zolpidem (13.2%).
A total of 3,806 (17.3 %) subjects experienced at least one DDI according to the 2019 AGS Beers Criteria®. DDIs mostly involved three or more CNS-active drugs (8.3%), two or more strong anticholinergics (7.5%), opioids with pregabalin or gabapentin (5.2%), opioids with benzodiazepines (3.6%), and corticosteroids with NSAIDs (1.4%).
Conclusion: This nationwide study showed that there was a high prevalence of PP and PIMs in older patients with cancer in Korea. Recognizing the high prevalence of PP and PIMs might be useful for triggering efforts to implement deprescribing interventions in cancer patients on chemotherapy.