Emerging Methods for Use of Real-World Clinical Data for Cardiovascular Outcomes Research

Abstract

The purpose of this dissertation is to describe methods for use of real-world data resources to study quality of care and outcomes for patients with critical limb ischemia. We used the Cerner Health Facts de-identified EHR database to 1) exclude patient records except those with critical limb ischemia from clinical sites in the Health Facts database, 2) document variability in patient outcomes after critical limb ischemia care, and 3) document variability in evidence-based medical therapy for the treatment of critical limb ischemia. We derived a data mart from the Health Facts database and identified 31,490 unique patients seen in 79,359 unique encounters at 233 unique clinical sites in the Health Facts database between 2010 and 2017. Of these, 20,204 encounters included endovascular peripheral vascular intervention. Within 30 days of the intervention, 2.8% of patient encounters resulted in a major amputation. We documented the association of modifiable patient factors with 30-day amputation and significant variation in 30-day amputation rates at the clinical site level. In addition to procedural quality outcomes, we examined rates of guideline directed medical therapy—medications indicated to reduce risk of adverse outcomes in all patients with critical limb ischemia. Only 27.2% of patient encounters documented complete medical therapy while 72.4% documented some component of therapy. As with 30-day amputation outcomes, rates of the medical therapy quality metric varied widely between sites with a median rate of 38.2% and interquartile range of 16.3-60.1%. This work demonstrates the use of a national, EHR database for cardiovascular outcomes research. We documented 30-day amputation outcomes after peripheral vascular intervention--a metric of CLI treatment outcomes. We also documented quality of care—guideline directed medical therapy—surrounding an inpatient encounter for CLI. We documented site variability for both treatment outcomes and quality of care to inform future quality improvement work in the treatment of CLI nationally.