Estimating Lung Cancer Screening Eligibility in the Veterans Health Administration Using Patient-Reported Smoking Histories

BACKGROUND: The Veterans Health Administration (VHA) serves a population at increased risk for lung cancer, but lung cancer screening (LCS) rates historically have been low. Understanding the size and characteristics of the screening-eligible population can provide insights for improving screening rates. Many screening eligibility recommendations rely on smoking intensity quantified in "pack-years," which historically has been challenging to obtain at scale from the medical record. Recent introduction of structured smoking data as part of VHA LCS efforts now allows for more robust identification and estimation of the screening-eligible population using a large body of patient-reported smoking histories. OBJECTIVE: To estimate the magnitude and characteristics of the LCS-eligible population served by the VHA nationwide based on United States Preventive Services Task Force (USPSTF) and American Cancer Society (ACS) recommendations. DESIGN: We performed a retrospective, cross-sectional analysis of nationwide VHA clinical and administrative data from 2015 to 2021. PATIENTS: Age-restricted Veterans with at least 1 outpatient visit from 2015 to 2021. KEY RESULTS: We identified a cohort of 1,422,573 Veterans with structured data to calculate exact pack-years smoking histories. We estimate that 23.1%(95% CI 23.0-23.2%) of Veterans nationwide aged 55-80 reported smoking histories meeting 2013 USPSTF criteria (721,122), 27.9% (28.8-30.0%) of individuals 50-80 met 2021 USPSTF criteria (1,042,301), and 28.0% (27.9-28.1%) met ACS criteria (1,046,409). We observed regional variation in eligibility, high rates of comorbid mental/cognitive illness or substance abuse, and variability in LCS eligibility among racial and ethnic groups. However, our estimates are not based on random sampling but rather on EHR data that may have selection or sampling bias, and should be interpreted within this context. CONCLUSIONS: We estimate over one-quarter of Veterans aged 50-80 meet LCS eligibility criteria, representing an estimated LCS-eligible population of over 1 million Veterans based on current USPSTF recommendations. Understanding the characteristics of this population could assist developing interventions to improve screening rates.