Correlation between ankle-brachial index, symptoms, and health-related quality of life in patients with peripheral vascular disease

Objective: Improving health-related quality of life (HRQL) is the main goal of surgery to treat peripheral vascular disease (PVD); however, HRQL is rarely measured directly. Rather, most surgeons use other measures, such as patient symptoms and ankle-brachial index (ABI) to determine the need for intervention in PVD. The accuracy of these surrogates in representing HRQL has been untested. The purpose of this study was to determine the correlation of these measures with HRQL in patients undergoing evaluation for intervention in symptomatic PVD. Methods: Patients (n = 108) referred to the vascular surgery service with symptoms of PVD were enrolled in a prospective study of HRQL. Patients completed two validated HRQL questionnaires: the short form-36 (SF-36) and the Walking Impairment Questionnaire (WIQ). All patients had symptoms consistent with PVD, including claudication (n = 69; 63.9%), ischemic rest pain (n = 17; 15.7%), or tissue loss (n = 22; 20.4%). ABI was measured at presentation. Results: The mean ABI was 0.53 (range, 0.00-0.98). The maximal correlation between SF-36 score and ABI was reflected in the Physical Component Summary score (r = 0.25). WIQ score also exhibited modest correlation with ABI, with maximal correlation noted for stair climbing (r = 0.26). Both SF-36 and WIQ scores exhibited a highly significant association with symptoms. Patients with more severe symptoms, such as lifestyle-limiting claudication or limb-threatening ischemia, had lower HRQL scores compared with patients with non-lifestyle-limiting claudication. Multi-variate analysis demonstrated that SF-36 and WIQ physical summary scores are better predicted by symptoms than by ABI (P < .01). Conclusions: HRQL in patients with PVD correlates weakly with ABI, but exhibits a closer association with vascular symptoms. However, neither variable fully expresses patient HRQL. These data suggest that sole reliance on these surrogates may not accurately reflect the effect of PVD on HRQL, or the potential benefit of vascular surgery in improving HRQL.