OBJECTIVES: Peripheral artery disease (PAD) is similar to coronary artery disease (CAD) in that they are both caused by atherosclerosis that narrows and blocks arteries in various critical regions of the body. An advanced form of PAD and CAD is the development of calcified lesions which are typically seen in the critical limb ischemia (CLI) and in complex CAD. This research uses real-world payer data to understand the prevalence of CLI and coronary artery calcification (CAC) in both the PAD and CAD populations. METHODS: Data for this study were derived from the MarketScan Commercial Database and the Medicare Supplemental and Coordination of Benefits Database from January 2006 - December 2014. Patients were eligible if they had a diagnosis of either PAD or CAD. Patients were categorized into the following cohorts based on their treatment pathway: [1] PAD only (with and without CLI), [2] CAD only (with and without CAC), or [3] PAD and CAD (with CLI only, with CAC only, with both, with none). RESULTS: A total of 6,981,758 patients met the inclusion criteria: 1,375,601 (20%) had PAD only, 4,429,217 (63%) had CAD only, and 1,176,940 (17%) had both PAD and CAD. Of the PAD only patients, 130,938 (10%) had a diagnosis of CLI. Of the CAD only patients, 180,740 (4%) had a diagnosis of CAC. For patients with both PAD and CAD, 881,626 (75%) had no record of calcification, 134,585 (11%) had CLI only, 126,716 (11%) had CAC only, and 34,013 (3%) had both CLI and CAC. CONCLUSIONS: This study found that a significant number of patients have PAD and CAD. Calcification in these patients is also a significant occurrence; therefore, testing for CLI and CAC should be performed.