Changes in female cancer diagnostic billing rates over the COVID-19 period in the Ontario Health Insurance Plan

Abstract

Background: The initial response to coronavirus disease 2019 (COVID-19) in Ontario included suspension of cancer screening programs and deferral of diagnostic procedures and many treatments. Although the short-term impact of these measures on female cancers is well documented, few studies have assessed the mid- to long-term impacts.

Objectives: To compare annual billing prevalence and incidence rates of female cancers during the COVID-19 period (2020-2022) to pre-COVID-19 levels (2015-2019).

Design: Retrospective analysis of aggregated claims data for female cancer diagnostic codes from the Ontario Health Insurance Plan (OHIP).

Methods: Linear regression analysis was used to fit pre-COVID-19 (2015-2019) data for each OHIP billing code and extrapolate counterfactual values for the years of 2020-2022. Excess billing rates were calculated as the difference between projected and actual rates for each year.

Results: In 2020, OHIP billing prevalence rates for cervical, breast, uterine, and ovarian cancers decreased relative to projected values for that year by -50.7/100k, -13.9/100k, -3.5/100k, and -3.8/100k, respectively. The reverse was observed in 2021 with rate increases of 47.8/100k, 59.1/100k, 2.5/100k, and 3.7/100k, respectively. In 2022, the excesses were further amplified, especially for cervical and breast cancers (111.2/100k and 78.67/100k, respectively). The net excess patient billing rate for 2020-2022 was largely positive for all female cancer types (108.3/100k, 123.7/100k, 5.2/100k, and 1.8/100k, respectively). Analysis of billing incidence rates showed similar trends.

Conclusion: The expected female cancer billing rate decreases in 2020 were followed by large increases in 2021 and 2022, resulting in a cumulative excess during the COVID-19 period. Further research is required to assess the nature of these changes.

Keywords: COVID-19; breast cancer; diagnostic claims; gynecological cancers; public health measures.

Figure 1.

Yearly OHIP 2015–2022 billing prevalence and incidence rates and the respective excess rates and standard scores for cervical (a–d), breast (e–h), uterine (i–l), and ovarian (m–p) cancer diagnostic codes. Linear regression fits to billing rates from pre-COVID-19 years (2015–2019) and the 95% CIs of the projected mean for COVID-19 years (2020–2022) are shown in billing rate plots. Note: Standard scores are only shown for the COVID-19 period years. CI, confidence interval; COVID-19, coronavirus disease 2019; n, number; OHIP, Ontario Health Insurance Plan.

Figure 2.

OHIP 2015–2022 billing patient count and incidence rates for disorders of menstruation (a, b) and menopause, postmenopausal bleeding diagnostic codes (c, d). n, number; OHIP, Ontario Health Insurance Plan.