Medication nonadherence is associated with higher morbidity after lower extremity revascularization in patients with peripheral arterial disease.

Abstract

Medical management of peripheral artery disease (PAD) consists of antiplatelet therapy, cholesterol reduction, blood pressure control, and anticoagulation. These medications are associated with lower mortality, improved quality of life, and fewer adverse limb events in patients with PAD. However, few studies have examined medication adherence rates, the factors that influence them, and the subsequent impact on outcomes. We identified all patients who underwent lower extremity endovascular revascularization for PAD between 05/2022-11/2024. Pharmacy dispense reports were utilized to calculate proportion of days covered (PDC) for 90 days postoperatively for antiplatelet agents, anticoagulants, statins, anti-hypertensives, insulin, and other anti-hyperglycemic agents. We evaluated the factors associated with nonadherence (defined as composite PDC less than 80%), and the association between nonadherence and reintervention, minor and major amputation, and 90-day mortality. There were 405 patients in our study population, of which 45% were female, 39% Hispanic, 18% current smokers, 22% had claudication, and 78% had chronic limb-threatening ischemia (CLTI) . Nonadherence rates ranged from 21.7% for sulfonylureas to 54.1% for short-acting insulin. In our sample, 62% met criteria for composite adherence. Patients with CLTI had 45% lower composite medication adherence compared to claudicants (87.7% vs 78.1%, p = 0.046). Ninety-seven patients underwent reintervention (24%), 68 (17%) underwent minor amputation, 39 (10%) underwent major amputation, 149 (37%) were readmitted within 90d, and 16 (4%) died within 90 days. While there was no difference in mortality (p = 0.90) between adherent and nonadherent patients, medication adherence was associated with 61% lower risk for death-censored reintervention (sHR 0.39, CI: 0.27-0.58, p < 0.001), 56% lower risk for death-censored major amputation (sHR 0.44, CI: 0.23-0.84, p = 0.01), and 45% lower risk for death-censored minor amputation (sHR 0.55, CI: 0.34-0.90, p = 0.02). Patients on dialysis had higher risk of minor amputation (p = 0.007), while patients with CLTI had higher risk for reintervention (p= 0.017), and minor amputation (p = 0.032). Insurance status and area deprivation index (ADI) were not associated with composite adherence. Medication nonadherence significantly increases the risk of reintervention and major/minor amputation following lower extremity endovascular revascularization. A significant proportion of are nonadherent to their medications following revascularization. Patients with CLTI comprise a high-risk group for nonadherence, with high rates of reintervention and amputation. Notably, traditionally accepted risk factors such as ADI and insurance were not associated with adherence, suggesting that significant work remains to understand the reasons why patients are nonadherent to medications.