Demonstrating the “susceptibility” of care delivery to regional market competition, M Libby Weaver (University of Virginia, Charlottesville, USA) presented the case that intermittent claudication (IC) is a “novel and underdefined” driver of practice variation in management of patients at the 2023 Southern Association for Vascular Surgery (SAVS) annual meeting (18-21 Jan, Rio Grande, Puerto Rico). Among Weaver’s most pointed messages: physicians and stakeholders must be called upon to alter procedural patterns to address the association between high competition and aggressive surgical management of vascular disease.
The research team behind the paper—first authored by Weaver—also included senior author Salvatore Scali (University of Florida, Gainesville, USA) and Caitlin Hicks and colleagues from Johns Hopkins Medicine (Baltimore, USA), a prolific investigator on the subject matter. Weaver was formerly a vascular fellow at Johns Hopkins Medicine.
Weaver began by outlining clinical practice guidelines set out by the Society for Vascular Surgery (SVS), which published recent appropriate use criteria (AUC) for the management of IC, which recommends best medical therapy (BMT) such as statin use and lifestyle modifications—which include smoking cessation and walking programmes, as first-line treatments prior to revascularisation.
Atherectomy and tibial-level interventions are not among the recommendations, and are specifically “advised against” in the treatment of IC, the presenter noted. Despite guidelines, Weaver continued, high market competition is incentivising physicians to treat patients by aggressive means. She noted how two thirds of interventional procedures for claudication include revascularisation and atherectomy, with an indication of claudication as a “predictor” of independent atherectomy use.
Although characteristics such as physician specialty and practice setting have “known” associations with atherectomy and tibial interventions, Weaver made clear that the causal relationship between IC management and regional competition has “not been explored” in clinical research.
Examining IC patients undergoing initial endovascular peripheral vascular intervention (PVI) in the SVS VQI from 2010–2022, the researchers assigned the Herfindahl-Hirschman Index (HHI)—a measure of regional physician market competition—to each centre based on Census Core-Based Statistical Area, assigning four pre-defined categories: very high competition (VHC), high competition (HC), moderate competition (MC), and low competition (LC).
Exclusion criteria were comprised of patients who underwent prior revascularisation procedures or had a non-claudication indication, a non-elective admission, or any missing data on their admission or indication status. Finally, Weaver confirmed that patients who were undergoing bilateral interventions, simultaneous atherectomy, or intervention at a treatment level categorised as aorta were excluded.
Their inclusion criteria identified 24,669 PVIs, revealing patients undergoing PVI in LC regions were more likely to be younger (66 vs. 69 years; p<.0001), white race (89% vs. 64%; p<0.0001), self-paid/uninsured (21% vs. 11%; p<0.0001), and active smokers (49% vs. 33%; p<0.0001). Continuing, Weaver drew attention to the “distinct treatment patterns” that became apparent when analysing index peripheral procedures, noting that the odds of patients being on BMT increased with greater market competition.
The probability of undergoing aortoiliac interventions also decreased with increasing competition (0.81–0.87; p<0.0001), but the research team’s results showed higher odds of receiving tibial (1.30–1.50; p<0.0001) and multi-level interventions in VHC vs. LC centres (femoral + tibial: 1.03–1.14; p=0.001). Primary stenting decreased as competition increased (0.87–0.92; p<.0001), while risk of undergoing atherectomy increased with HC (1.11–1.19; p<0.0001). 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=0.004) and current smoking status lower (VHC 30% vs. LC/MC/HC 38%; p<0.0001) in VHC centres. However, odds of undergoing balloon angioplasty (34% vs. 28%: odds ratio [OR] 0.7, 0.6–0.8; p<0.0001) and primary stenting only (41% vs. 34%: OR 0.7, 0.6–0.8; p<0.0001) were higher in LC/MC/HC centres, while likelihood of receiving atherectomy remained significantly higher among VHC centres (35% vs. 22%: OR 1.9, 1.7-2.1; p<0.0001), suggesting disease severity is not a primary driver of these treatment differences.
Highlighting a clear trend in their results, Weaver posited: “Notably, analogous procedural associations were identified even among a subset of patients with TASC C and D lesions; however, compliance to BMT was significantly better in lower- as compared to higher-competition centres.”
Moreover, matching the entire patient cohort based on cardiovascular risk factors and characteristics known to impact PVI outcomes, market competition adherence to BMT was “no longer evident,” Weaver said. However, patients managed in very high competition regions remain “significantly” more likely to receive atherectomy or tibial-level interventions and less likely to undergo stenting, with or without angioplasty alone, across all intergroup comparisons, Weaver concluded.
Importantly, Weaver and colleagues emphasised that the overall correlation between high regional competition and inadvisable IC procedures “persisted” even when correcting for disease severity and comorbidities. Furthermore, addressing the correlation seen between increased BMT in HC regions, Weaver conveyed that this was also linked to “increased likelihood” of tibial- and multi-level interventions as well as atherectomy use.
Weaver believes their analysis demonstrates the “susceptibility of care delivery to regional market competition,” signifying an unconsidered “driver” of practice variation in management of patients with IC. Going forward, Weaver observed that this “novel” factor appears to play an “important role” in treatment patterns and placed emphasis on the important role healthcare providers must assume to design incentives which remedy these disparities, while encouraging “adherence to evidence-based treatment recommendations” to improve overall quality of claudication care.
Weaver and her team contend that stakeholders must implement processes and policies of care to facilitate education for IC patients, ensuring information is being shared so that they may become “better informed regarding best practices” and make more informed decisions over their choice of treatment.