The Ann Arbor VA IRB deemed this study exempt from review. This was a retrospective observational study using VHA administrative, clinical, and laboratory data available in the Corporate Data Warehouse (CDW). The study population included Veterans undergoing a screening colonoscopy at one of 109 VA endoscopy facilities in October-December 2019 (“pre-COVID”) and October-December 2020 (“COVID”). Rates of screening colonoscopy overuse were estimated using an ICD-10-based electronic measure recently validated for use in VHA (specificity 99%, sensitivity 46%) and further detailed below14.

Measure Specification and Electronic Measure Construction

Measure specifications were initially defined by an expert workgroup comprising VA experts in colorectal cancer screening and in performance measurement11. Prior to the initial workgroup meeting, members were provided with relevant literature to review, including U.S. Preventive Services Task Force (USPSTF) guidelines for colorectal cancer screening and Veterans Health Administration (VHA) Colorectal Cancer Screening Directives in effect at the time of measure development. Workgroup members were charged with developing a measure that: (1) was based on high-quality evidence (i.e., the evidence summarized in pre-2021 USPSTF guidelines); (2) maximized specificity at the expense of sensitivity; and (3) could be implemented electronically. The final measure defined by the workgroup identified average-risk screening colonoscopies (comprising the eligible population in the denominator – Table 1) that met one or more criteria for probable or possible overuse (comprising the numerator – Table 1). For purposes of this study, we adapted the measure slightly by eliminating the 45-49-year age overuse category included in the original measure numerator given 2021 updates to USPSTF guidelines that recommended changing the age of screening initiation from 50 to 45 years old15.

Table 1 Numerator, Denominator and Exclusions for Screening Colonoscopy Overuse MeasureElectronic Approximation of Measure Denominator

The measure denominator (prior to application of exclusions to eliminate procedures with indications other than average-risk screening) consisted of all index colonoscopies performed during the study period in patients who had not had a colonoscopy within the preceding 12 months. To approximate the measure denominator (Table 1), we first identified all colonoscopies performed for any indication using Current Procedural Terminology (CPT) and Healthcare Common Procedure Coding System (HCPCS) codes (for a detailed list of codes, see Adams et al.14). For patients who had more than one colonoscopy performed in the study period, only the first (index) procedure was included in the denominator. Likewise, only patients who had no prior colonoscopy performed in the 12 months preceding the index colonoscopy were included in the denominator. This is because when a colonoscopy is repeated within a year, there is a high probability that the repeat procedure was done for a reasonable indication such as inadequate bowel preparation on the prior procedure, sedation intolerance leading to an incomplete procedure, or failure to complete the prior procedure due to technical difficulty.

Denominator Exclusions (Exclusion of Non-Average-Risk Screening Colonoscopies)

We then excluded procedures that may have been performed for diagnostic or high-risk screening or surveillance indications, using an approach previously developed and validated by Fisher and colleagues16. First, we excluded patients who had an ICD-10 code for specific gastrointestinal symptoms or for colorectal neoplasia within 12 months of the Q4 2019/Q4 2020 colonoscopy14. To further increase the specificity of the electronic measure, we also excluded individuals with ICD-9 and ICD-10 codes indicating high risk for colorectal cancer or prior total abdominal colectomy at any time in the prior 10 years. Specifically, patients were excluded if CPT or ICD-9/-10 codes revealed any of the following diagnoses within 10 years of the qualifying Q4 2019/Q4 2020 colonoscopy: (1) prior colectomy, (2) history of colorectal cancer; (3) history of colon polyps; (4) history of inflammatory bowel disease; or (5) family history of colorectal cancer. Both ICD-9 and ICD-10 codes were used because VHA (like most US healthcare systems) transitioned between these two coding systems on October 1, 2015. These additional exclusion criteria were selected to ensure that the cohort comprised individuals who were at average (rather than increased) risk of CRC. Finally, we excluded individuals who underwent their colonoscopy during a hospitalization (since such colonoscopies are unlikely to be performed for screening). Thus, the final denominator (after all exclusions) consisted of all average-risk screening colonoscopies performed in the study period.

Electronic Approximation of Measure Numerator

Specification of electronic elements comprising the measure numerator (probable and possible overuse – Table 1) was more straightforward than for the denominator since these elements were primarily based on factors such as patient age and the time interval between colonoscopies (which are reliably-coded in administrative data). To identify fecal occult blood tests (FOBTs), we used Logical Observation Identifiers Names and Codes (LOINC)14. To identify patients with life expectancy <6 months, we used structured data from CDW that is used to indicate limited life expectancy for clinical purposes (i.e., the CDW Health FactorType domain, which contains information about health factors, severity level, and other indicators of health and includes a forecast of the probable outcome of a disease to flag patients with a life expectancy of <6 months17).

Changes in Screening Colonoscopy Overuse & Predictors

Facility-level rates of screening colonoscopy overuse were calculated pre-COVID and COVID using the electronic measure and adjusted for facility endoscopy volume. 95% confidence intervals (CI) were calculated. Facilities that performed <10 screening colonoscopy procedures in either the pre-COVID or COVID periods were excluded. A sensitivity analysis assessing Q4 2021 overuse rates also was performed to capture potential longer-term changes in overuse during the pandemic.

We also examined the association between certain facility-level predictors and changes in screening colonoscopy overuse. Facility characteristics examined included: (1) VHA facility complexity score (ranging from 1a (highest) to 3 (lowest)), (2) geographic region (Supplemental Table),18 (3) academic affiliation, and (4) capacity (comparing Q3 2020 procedural volume with Q3 2019 volume to calculate proportion of pre-COVID/Q4 2019 capacity recovered in Q4 2020). Procedure-level data was aggregated by facility and time-period. We then fit a generalized estimating equation negative binomial model with the number of overuse screening colonoscopies as the outcome, the total number of screening colonoscopies as the offset, and time-period (Q4 2019/Q4 2020), geographic region, facility complexity, academic affiliation, capacity, and interactions of time-period with facility complexity, academic affiliation, geographic region, and capacity as predictors. The model assumed that observations from the same facility were correlated with an exchangeable covariance structure. To examine the association between patient characteristics and changes in screening colonoscopy overuse, we estimated relative risk (RR) by Poisson regression with robust error variance using procedure-level data that included only patient-level factors -- specifically, race (black, non-black), sex (male, female), engagement in VA care (as measured by the number of primary care visits in the previous 12 months; 0-1, 2-4, >4), time-period (Q4 2019/Q4 2020), and the interactions of time-period with race, sex, and engagement in VA care. Data analysis was performed using SAS, Version 9.4 (SAS Institute Inc., Cary, NC) and STATA 16 (StataCorp, College Station, TX).