Market Competition Influences Practice Patterns in Management of Patients with Intermittent Claudication in the Vascular Quality Initiative
M. Libby Weaver1, Dan Neal2, Jesse A Columbo3, Courtenay M Holscher4, Rebecca A Sorber4, Caitlin W Hicks4, David H Stone3, W. Darrin Clouse1, Salvatore Scali2
1University of Virginia Health System, Charlottesville, VA;2University of Florida College of Medicine, Gainesville, FL;3Dartmouth-Hitchcock Medical Center, Lebanon, NH;4The Johns Hopkins Medical Institutions, Baltimore, MD
INTRODUCTION: The Society for Vascular surgery(SVS) clinical practice guidelines recommend best medical therapy(BMT) and smoking cessation prior to revascularization of patients with intermittent claudication(IC). Notably, atherectomy and tibial-level interventions are generally discouraged in IC management; however, high regional market competition may incentivize physicians to treat patients more aggressively. We sought to determine the association between regional market competition and index endovascular treatment of IC patients.
METHODS: We examined IC patients undergoing initial endovascular peripheral vascular intervention(PVI) in the SVS-VQI from 2010-2022. We assigned the Herfindahl-Hirschman Index(HHI), a measure of regional physician market competition established by the Health Care Cost Institute, to each center based on Census Core-Based Statistical Area using four pre-defined categories: very high competition(VHC), high competition(HC), moderate competition(MC), and low competition(LC). We defined BMT as preoperative documentation of being on an antiplatelet medication, statin, non-smoking status, and a recorded ankle-brachial index. We used logistic regression to evaluate the association of market competition with patient and procedural characteristics. We performed a sensitivity analysis in patients with isolated femoropopliteal disease matched by TransAtlantic InterSociety Consensus(TASC) classification of disease severity.
RESULTS: 24,669 PVIs met inclusion criteria. Patients undergoing PVI in LC regions were more likely to be younger(66 vs. 69 years;p<.0001), white race(89% vs. 64%;p<.0001), self-pay/uninsured(21% vs. 11%;p<.0001), and active smokers(49% vs. 33%;p<.0001)(Table). The odds of being on BMT increased with market competition(OR multiplies 1.07 per class step-up, 95%CI 1.04-1.11;p<.0001). The probability of undergoing aortoiliac interventions decreased with competition(OR multiplies 0.84 per class step-up, 0.81-0.87;p<.0001), but there were higher odds of receiving tibial(OR 1.4, 1.30-1.50;p<.0001) and multi-level interventions in VHC vs. LC centers(femoral+tibial: OR 1.1, 1.03-1.14;p=.001). Primary stenting decreased as competition increased(OR 0.89, 0.87-0.92;p<.0001), while risk of undergoing atherectomy increased with higher market competition(OR 1.15, 1.11-1.19;p<.0001). In subgroup analysis limited to patients undergoing single-artery femoropopliteal intervention with TASC A or B lesions(N=5,685), compliance with BMT remained higher(VHC 36% vs. LC/MC/HC 32%;p=.004) and current smoking status lower(VHC 30% vs. LC/MC/HC 38%;p<.0001) in VHC centers. However, odds of undergoing balloon angioplasty(34% vs. 28%: OR 0.7, .6-.8;p<.0001) and primary stenting only(41% vs. 34%: OR 0.7, .6-.8;p<.0001) were higher in LC/MC/HC centers, while likelihood of receiving atherectomy remained significantly higher among VHC centers(35% vs. 22%: OR 1.9, 1.7-2.1;p<.0001), suggesting disease severity is not a primary driver of these treatment differences(Figure).
CONCLUSIONS: High market competition was associated with more aggressive procedures among claudication patients, including atherectomy and tibial interventions. This analysis demonstrates the susceptibility of care delivery to regional market competition and signifies a novel and undefined driver for variation in PVI for patients with claudication. This understudied factor appears to play an important role in physician practice patterns, and underscores the need for patients to be informed regarding best practices for their disease processes.
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