Identifying smoking status and smoking cessation using a data linkage between the Kentucky Cancer registry and health claims data

PURPOSE Linkage of cancer registry data with complementary data sources can be an informative way to expand what is known about patients and their treatment and improve delivery of care. The purpose of this study was to explore whether patient smoking status and smoking-cessation modalities data in the Kentucky Cancer Registry (KCR) could be augmented by linkage with health claims data. METHODS The KCR conducted a data linkage with health claims data from Medicare, Medicaid, state employee insurance, Humana, and Anthem. Smoking status was defined as documentation of personal history of tobacco use (International Classification of Diseases, Ninth Revision [ICD-9] code V15.82) or tobacco use disorder (ICD-9 305.1) before and after a cancer diagnosis. Use of smoking-cessation treatments before and after the cancer diagnosis was defined as documentation of smoking-cessation counseling (Healthcare Common Procedure Coding System codes 99406, 99407, G0375, and G0376) or pharmacotherapy (eg, nicotine replacement therapy, bupropion, varenicline). RESULTS From 2007 to 2011, among 23,703 patients in the KCR, we discerned a valid prediagnosis smoking status for 78%. KCR data only (72%), claims data only (6%), and a combination of both data sources (22%) were used to determine valid smoking status. Approximately 4% of patients with cancer identified as smokers (n = 11,968) and were provided smoking-cessation counseling, and 3% were prescribed pharmacotherapy for smoking cessation. CONCLUSION Augmenting KCR data with medical claims data increased capture of smoking status and use of smoking-cessation modalities. Cancer registries interested in exploring smoking status to influence treatment and research activities could consider a similar approach, particularly if their registry does not capture smoking status for a majority of patients.