Polypharmacy and potentially-inappropriate medications are prevalent in the elderly cancer patients receiving systemic cancer therapy and they co-relate with adverse outcomes
Authors: Bandidwattanawong Chanyoot , Rattanaserikulchai Pat , Jetsadavanit Nontakorn 
Published: November 2023

Abstract
Objectives
Cancer is the disease of the ageing. Most of the elderly cancer patients have pre-existing illnesses requiring complexity of medical care. Excessive medications would lead not only futility, but also result in adverse outcomes especially if such over-prescription is not appropriate. This study was intended to determine the prevalence of polypharmacy (PP) and potentially-inappropriate medications (PIMs) among elderly cancer patients eligible for active cancer care and their associations with hospitalization and mortality.

Materials and methods
This was a prospective cohort study conducted among the elderly non-hematologic cancer patients (≥ 65 years old) whom a medical oncologist had decided suitable for systemic cancer therapy. Demographic data including age, sex, primary site of cancer, cancer stage at diagnosis, Charlson Comorbidity Index (CCI), numbers and kinds of medications used both prior to and during cancer treatment were recorded. Hospitalizations not related to systemic cancer therapy administration and mortality were prospectively monitored. All of the patients had to be followed at least one year after cancer diagnosis.

Results
There were 180 eligible participants. Median age in years (IQR) was 68 (65–73). One hundred patients (55.56%) were male and 80 patients (44.44%) were female. Breast (35, 19.44%), lung (31, 17.22%) and colorectal (18, 10%) cancers were the most common diagnoses. Eighty-six patients (47.78%) had metastatic disease at cancer diagnosis. One hundred twenty-two patients (67.78%) had PP (5 or more medications a day) and thirty-six patients (20%) had hyper-PP (10 or more medications a day). One hundred twenty five of the whole cohort (69.4%) had PIMs. Patients with more serious CCI scores were associated with PP and hyper-PP. While patients with primary lung cancer was only the only factor associated with PIMs. When excluding opioids, laxatives and anti-emetics, the most frequently prescribed drugs during cancer treatment, the so-called corrected PP did not associate with worse 1-year survival. Factors correlated with 1-year mortality were more advanced age group (70 years old or more) (OR 2.24; 95% C.I., 1.14–4.41; p = 0.019), primary lung cancer (OR 2.89; 95% C.I., 1.45–5.78; p = 0.003), metastatic disease at cancer diagnosis (OR 4.57; 95% C.I., 1.90–10.97; p = 0.001), and unplanned hospitalizations (OR 3.09; 95% C.I.,1.60–5.99; p = 0.001). While male gender (OR 2.35; 95% C.I., 1.17–4.71; p = 0.016), metastatic stage at cancer diagnosis (OR 2.74; 95% C.I., 1.33–5.66; p = 0.006) and corrected PP (OR 1.90; 95% C.I. 1.01–3.56; p = 0.046) were the significant predictive factors of unplanned hospitalizations.

Conclusion
Among elderly cancer patients suitable for systemic cancer therapy, around two thirds of patients had PP and PIMs. Higher CCI score was the only significant predictor of PP and hyper-PP; while primary lung cancer was the sole independent factor predicting PIMs. PP was associated with unplanned hospitalizations, albeit not the survival.