Changes to Patterns of Oncology Medicine Dispensing in Response to the Onset of the COVID-19 Pandemic in Ireland: An Interrupted Time Series Analysis

Abstract

Background: The onset of the COVID-19 pandemic disrupted oncology healthcare provision in most countries. The purpose of this study is to examine how the onset of COVID-19 influenced changes in dispensing dynamics of systemic anti-cancer therapy (SACT) medications from four drug classes: (i) chemotherapeutics; (ii) immunotherapies; (iii) endocrine therapies; and (iv) targeted therapies. Methods: Monthly pharmacy claims data from community and hospital reimbursement schemes were extracted and analyzed using interrupted time series analysis (ITSA) and autoregressive integrated moving average (ARIMA) models with March 2020 as the first interruption. Results: Thirteen medications (65%) from across all four SACT classes were found to have increasing dispensing rates before March 2020 (3 chemotherapies, 3 endocrine therapies, 3 immunotherapies, and 4 targeted therapies). Nine (69.2%) of these 13 SACT medications had decreasing rates of dispensing post-March 2020 (100% of chemotherapies, 75% targeted therapies, 33% immunotherapies, and 66% endocrine therapies). Regardless of drug class, three (15%) medications showed increasing rates of dispensing post-March 2020. Discussion: Most dispensed SACT medications examined demonstrated changes in dispensing, particularly immunotherapies, after the onset of COVID-19. Changes in dispensing may be associated with aspects of healthcare disruption and clinical decision making at the time to help mitigate adverse outcomes for cancer patients.