Effects of the different periods and magnitude of COVID-19 infection spread on cancer operations: Interrupted time series analysis of medical claims data

Background No clear evidence exists regarding the effects of the different periods and magnitude of spread of the COVID-19 infection on cancer treatments. This study investigated the effects of the different periods and magnitude of COVID-19 infection spread on in-hospital cancer operations. Methods Medical claims data from 17 hospitals where in-hospital operations for patients with malignant neoplasms were performed between 1 April 2017 and 31 March 2021 in Yamagata were extracted and analyzed. The critical time points as exposure used to evaluate the impact of different COVID-19 infection spread periods on cancer operations were (1) April 2020 (emergency declaration introduced by the government) and (2) December 2020 (the second wave). From April to November 2020 and December 2020 to March 21, the number of confirmed COVID-19 cases was 130 and 840, respectively. The 17 hospitals were classified into intervention or control groups based on whether in-hospital treatments for patients with COVID-19 were provided. Results The interrupted time series analysis reported that the difference in the trend of pre-COVID-19 and postsecond wave (March 2020 to December 2020) periods was statistically significant between groups, with 50.67 fewer operations (95% confidence interval [CI] = 12.19-89.15) performed per month in the intervention group compared with the control group. Moreover, the immediate change in the number of operations in April 2020 (beginning of the first wave) was statistically significant between groups, with 80.14 operations (95% CI = 39.62-120.67) less immediately after the first wave in the intervention group compared with the control group. Conclusion Our findings suggest that a statement of emergency by the government and the COVID-19 infection spread are both associated with the number of cancer operations performed in the Yamagata prefecture during the COVID-19 pandemic.