Oral Presentation 2025 Joint Meeting of the COSA ASM and IPOS Congress

Factors associated with polypharmacy and potentially inappropriate medication use in older adults with cancer. (126589)

Sam Maleki 1 , Josephine Foo 1 , Deena Tumber 1 , Siena Bullen 2 , Kelly Cheung 2 , Mohammadali Mirzai 2 , Shanley Pillai 2 , Tiffany Xia 2 , Emily Schembri 3 , Justin Turner 2 , Wee Kheng Soo 3 4 5 , Carl Kirkpatrick 2
  1. Pharmacy Department, Eastern Health, Box Hill, Victoria, Australia
  2. Faculty of Pharmacy and Pharmaceutical Sciences, Centre for Medicine Use and Safety, Monash University, Melbourne, Victoria, Australia
  3. Eastern Health Clinical School, Monash University, Melbourne, Victoria, Australia
  4. Cancer Services, Eastern Health, Box Hill, Victoria, Australia
  5. Aged Medicine Program, Eastern Health, Box Hill, Victoria, Australia

Background: Polypharmacy (≥5 medications) is common among older adults with cancer and is associated with increased hospitalisation, morbidity and mortality1. Understanding risk factors for polypharmacy and potentially inappropriate medication (PIM) use may inform targeted deprescribing to improve medication safety.

Aim: To identify patient and treatment characteristics associated with polypharmacy and PIM use among older adults with cancer.

Method: This retrospective cross-sectional study included inpatients aged ≥65 years, admitted to a metropolitan hospital cancer service in Victoria from Jan-Dec 2024. Patients were eligible if pharmacy medication reconciliation was completed on admission. Patients with limited life expectancy were excluded. PIMs were identified using STOPP criteria. Multivariate logistic regression assessed associations between polypharmacy and PIMs, adjusting for age, sex, tumour type, anticancer treatment, and comorbidities.

Results: Of 278 eligible patients (median age 77.0 years; range: 65-98; 44.6% female), haematological (38.5%), gastrointestinal (18.0%), genitourinary (15.1%) and respiratory (14.4%) malignancies were most common. Polypharmacy was present in 79.1% (n=220) of patients, and 32.4% (n=90) had ≥1 PIM. Half (n=139, 50.0%) had active or recent anticancer treatment, including chemotherapy (31.3%) and non-cytotoxic treatment (18.7%) e.g. targeted therapy, immunotherapy or hormonal therapy.

After adjustment for confounders, anticancer treatment (adjusted odds ratio (aOR) 2.23; 95%CI: 1.11–4.47) and opioid use (aOR 5.35; 95%CI: 1.79–20.61) were associated with polypharmacy. Increased comorbidity was associated with both polypharmacy (aOR 1.58, 95%CI: 1.28–1.95) and PIMs (aOR 1.18, 95%CI: 1.03–1.36).

Conclusions: This study identified key patient and treatment factors associated with polypharmacy in older adults with cancer, including anticancer therapy, opioid use, and higher comorbidity burden. The fivefold increased odds of polypharmacy with opioid use highlights a potential focus for medication review. These findings support the need for further research using validated deprescribing tools adapted to older adults with cancer to optimise medication management in this population.

  1. Khezrian M, McNeil CJ, Murray AD, Myint PK. An overview of prevalence, determinants and health outcomes of polypharmacy. Ther Adv Drug Saf. 2020;11:2042098620933741.