CLIPPER Study of Large Medicare Cohort Seeks to Inform Quality-of-Care Improvements for CLTI

May 19, 2023—The Society for Cardiovascular Angiography & Interventions (SCAI) announced that the CLIPPER cohort of 1 million patients with chronic limb-threatening ischemia (CLTI) found that one in six patients with CLTI died within their first year of diagnosis and 50% survived at 5 years. Using data from Medicare, the CLIPPER cohort was created to develop and test process measures for CLTI that could ultimately be used to measure and improve the quality of care.

Alexander Fanaroff, MD, Assistant Professor of Medicine at the University of Pennsylvania in Philadelphia, Pennsylvania, is the lead author of the study. The findings were presented as late-breaking clinical research at the SCAI 2023 Scientific Sessions held May 18-20 in Phoenix, Arizona.

According to SCAI, the CLIPPER investigators used a coding algorithm to identify patients with CLTI within inpatient and outpatient claims data from patients with fee-for-service Medicare from 2010 to 2019. To qualify for a CLTI diagnosis, patients had either of the following:

1. One diagnostic code for peripheral artery disease and one diagnostic code for ulceration, infection, or gangrene on the same inpatient or outpatient claim
2. One CLTI-specific diagnostic code, as well as a procedure code indicating arterial vascular testing within 6 months before or after the qualifying CLTI diagnostic code(s)

As summarized in the SCAI press release, the cohort was composed of 1,130,065 patients diagnosed with CLTI between 2010 and 2019. The mean age of the cohort was 75 ± 5.8 years; 48.4% were women; and 14.6% were Black. 

Within 30 days of CLTI diagnosis, 20.4% of patients underwent percutaneous or surgical revascularization. Within 6 months, 3.3% of patients underwent major amputation. At 1-year follow-up, 16.7% of patients had died. At 5-year follow-up, 50.3% of patients had died.

“CLTI is an incredibly deadly disease if not treated quickly after diagnosis, but we know very little about how hospitals perform with respect to treatment,” commented Dr. Fanaroff in the SCAI press release. “Comprehensive process measures are needed for patients in order to advance care and improve the chance of survival. Our hope is that this study is a first step toward developing better process measures.”

SCAI reported that the investigators plan for the CLIPPER data to be used for future studies on CLTI, including developing process measures that can be captured from administrative claims data, and measuring their association with limb outcomes and corresponding racial, ethnic, socioeconomic, gender-based, and geographic variability.