Adherence to oral chemotherapy medications among gastroenterological cancer patients visiting an outpatient clinic

The purpose of this study was to investigate medication adherence to oral chemotherapy medications and determinants of medication non-adherence to them among gastroenterological cancer patients. A cross-sectional study was conducted on 117 consecutive, consenting, eligible patients visiting an outpatient clinic of university hospital in Japan. Good medication adherence was defined as taking 100% of the prescribed dose. Medication adherence was measured via self-report. We hypothesized that there was a significant relationship between medication non-adherence and the five factors defined by the World Health Organization: patient-related, socioeconomic-related, condition-related, treatment-related, and healthcare-system/provider-related factors. Multiple logistic regression models were used to identify factors associated with oral chemotherapy medication non-adherence. The proportion of patients showing good medication adherence was 56.4%. The multiple logistic regression analysis revealed that the determinants of medication non-adherence to oral chemotherapy medications included having a history of patient-caused treatment interruptions due to worsening of symptoms (adjusted odds ratio [AOR] = 9.59, 95% confidence interval [CI] = 1.38-66.47), having diarrhea (AOR = 3.25, 95% CI = 1.13-9.34), experiencing pain (AOR = 0.17, 95% CI = 0.05-0.55), taking oral chemotherapy medication every 8 h (AOR = 5.52, 95% CI = 1.71-17.81), and diminished sense of priority for medication (AOR = 1.40, 95% CI = 1.21-1.63). This study suggests that many patients with gastroenterological cancer were non-adherent to oral chemotherapy medications. It might be necessary to conduct periodic screening and connect patients at a high risk of medication non-adherence to appropriate support.