Polypharmacy in the elderly cancer patients receiving systemic therapy is associated with more unpredicted hospitalizations.

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%), pulmonary (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 medications a day) and thirty-six patients (20%) had hyper-PP (> 10 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. Factors correlated with 1-year mortality were more advanced age group (70 years old or more) (OR 2.244; 95% C.I.,1.14-4.415; p = 0.019), primary pulmonary cancer (OR 2.892; 95% C.I.,1.448-5.775; p = 0.003), metastatic disease at cancer diagnosis (OR 4.459; 95% C.I.,1.903-10.97; p = 0.001), and repeated unexpected hospitalizations (OR 3.093; 95% C.I.,1.597-5.989; p = 0.001). The corrected PP (excluding opioids, laxatives and anti-emetics) did not associate with 1-year survival. While male gender (OR 2.349; 95% C.I., 1.173-4.706); p = 0.016), metastatic stage at cancer diagnosis 2.742; 95% C.I., 1.328-5.663; p = 0.006) and corrected PP (OR 1.898; 95% C.I. 1.012-3.557; p = 0.046) were the significant predictive factors of repeated unexpected 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; while primary pulmonary cancer was the sole independent factor predicting PIMs. PP was associated with repeated unexpected hospitalization, albeit not the survival.