Amputations among younger patients with chronic limb threatening ischemia (CLTI) may carry higher personal and societal costs, but younger patients are often not included in CLTI research because of dataset limitations. We aimed to characterize and compare outcomes between younger (<65 years old) and older patients with CLTI.

This retrospective cohort study identified patients with CLTI between July 1, 2014 and December 31, 2017 in the MarketScan commercial claims database, a proprietary set of claims for over 50 million patients with private insurance in the United States. The primary outcome was major adverse limb events (MALE); secondary outcomes included amputations, major adverse cardiovascular events, and statin prescription fills.

The study cohort included 64,663 people with CLTI, of whom 25,595 (39.6%) were <65 years old. Younger patients were more likely to have diabetes mellitus (54.1% versus 49.9%, P<.001) but less likely to have other comorbidities. A higher proportion of younger patients suffered MALE (31.7% versus 30.2%, P=.002), specifically amputation (11.5% versus 9.3%, P<.001). After adjustment, age <65 years old was associated with a 24% increased risk of amputation (HR_adj 1.24, 95%CI 1.18-1.32, P<.001) and a 10% increased risk of MALE (HR_adj 1.10, 95%CI 1.07-1.14, P<.001).

A significant proportion of commercially insured patients with CLTI are under the age of 65, and younger patients have worse limb-related outcomes. These findings highlight the importance of aggressively treating risk factors for atherosclerosis and intentionally including younger patients with CLTI in future analyses to better understand their disease patterns and outcomes.