https://orcid.org/0000-0003-3340-1428
Abstract
Purpose
To evaluate the rate and predictors of non-adherence to imatinib in gastrointestinal stromal tumor (GIST) patients, as well as to compare the difference in health-related quality of life (HRQOL) between adherent and non-adherent patients.
Patients and Methods
A cross-sectional study at the Oncology Clinic, Hospital Kuala Lumpur was conducted from March to August 2018. All patients with metastatic and/or unresectable GIST aged ≥18 years old and on at least 3 months of imatinib were included. Adherence to imatinib was assessed using the 10-item validated Medication Compliance Questionnaire, with a score of <100% indicating non-adherence. Non-adherence predictors were determined by multiple logistic regressions. HRQOL was evaluated by the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). The difference in the mean HRQOL scores between adherent and non-adherent groups was determined by multivariate analysis of variance.
Results
A total of 89 patients were enrolled, of which 49 (55.1%) were considered non-adherent. The significant predictors of non-adherence were age (adjusted odds ratio [OR] 0.93; CI 0.89–0.98; P = 0.007), presence of nausea and vomiting (OR 5.63; CI 1.25–25.27; P = 0.024), and presence of comorbidities (OR 4.56; CI 1.44–14.40; P = 0.010). Patients who were in the adherent group showed significantly better score in overall HRQOL, F (15, 73) = 2.09, P < 0.02; Pillai’s trace = 0.3, partial eta squared = 0.30.
Conclusion
Non-adherence to long-term treatment with imatinib among patients with GIST should not be underestimated. Significant predictors of non-adherence among this population are younger age, presence of nausea and vomiting, as well as comorbidities. Patients with good adherence portrayed better HRQOL.
Acknowledgments
We would like to thank the Director-General of Health Malaysia for his permission to publish this article. We would also like to thank the Director and the Head of Pharmacy Department of Kuala Lumpur Hospital for providing administrative support for this study. We would also like to acknowledge Madam Malathi a/p Sriraman and Madam Nurfarahana Hafzan Mahmud for their involvement in the proposal development. We would like to thank Madam Hannah Abdul Halim for the useful discussion during data analysis. This study was not funded by any organization.
Disclosure
The authors report no conflicts of interest in this work.