Variability in Guideline-Directed Medical Therapy Across Sites and Operators and Long-Term Mortality and Amputation Outcomes Risk in Patients Undergoing Peripheral Vascular Interventions.

BACKGROUND: The use of guideline-directed medical therapy (GDMT) in patients undergoing peripheral vascular interventions (PVIs) decreases the risk of death and amputation and may decrease hospital readmissions. The variability of GDMT prescription across sites and operators and the proportionality of risk is not well understood. We aimed to study the association between variability of GDMT prescription at the site and operator level and outcomes (including 90-day readmissions and 24-month all-cause mortality and major amputation).

METHODS: We examined GDMT discharge rates in PVIs performed between 2017 and 2018 using Medicare-linked Vascular Quality Initiative registry. GDMT included a statin, antiplatelet therapy, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACE-i/ARB) if hypertensive. Quartiles (Q1-4) of GDMT rates were documented by operators and sites and variability was quantified using median odds ratios (MOR) and intraclass correlation (ICC). The association between lower GDMT rates (per 10%) by sites and operators with 90-day readmission were calculated using logistic regression, and with 24-month mortality and major amputation using parametric survival model. Models were adjusted for patient-level factors and included sites and operators nested within sites as two random effects.

RESULTS: GDMT rates for 17,147 patients across 223 sites and 1,263 operators ranged from 0%-38% (Q1, MOR 1.43, 95% CI 1.39-1.47, p ≤.001) to 57%-100% (Q4, MOR 1.48, 95% CI 1.44-1.51, p≤.001). Four percent of variance in GDMT use was explained by sites (ICC 3.9, 95% CI 2.9-5.3) and operators (ICC 4.1, 95% CI 3.1-5.4). A dose-response relationship was noted between lower GDMT rates and increased risk of 90-day readmission risk by sites (p=0.021) and operators (p<0.001). Lower GDMT prescription by site was associated with higher risk of 24-month mortality (HR=1.07, 95% CI 1.02-1.13) and major amputation (HR=1.08, 95% CI 1.01-1.15). Similar associations were found for GDMT use by provider (mortality HR=1.05, 95% CI 1.02-1.08 and amputation HR=1.04, 95% CI 1.00-1.08).

CONCLUSION: Both at the operator and health system level, there was significant variability in GDMT prescription following PVI, proportionally translating into risk for readmission, mortality, and major amputation. Targeted quality efforts should prioritize both operator and site levels to improve GDMT use and outcomes for patients undergoing PVI.