We evaluated whether altered reporting of ischemic symptoms occurs in diabetic patients with peripheral arterial disease (PAD) and stable claudication. Patients (n = 152) with claudication were enrolled (120 males; mean age: 71.0 ± 8.6 years): 74 with diabetes (DM-PAD) and 78 without (DMfree-PAD). The degree of muscle oxygenation at symptom onset and maximal speed (Smax) during an incremental treadmill test was recorded at the gastrocnemius by near-infrared spectroscopy (NIRS) and quantified by area under the curve of oxygenated hemoglobin (AUC-Hbo 2) and area under the curve of differential hemoglobin (AUC-dHb). The DM-PAD and DMfree-PAD showed similar exercise capacities inversely correlated with the degree of muscle oxygenation but significantly lower values of AUC-Hbo 2 and AUC-dHb for DM-PAD at symptom onset and Smax (-356 vs -122 and -1200 vs -359, P < .0001). During a NIRS-assisted test, the report of claudication in the presence of diabetes was delayed, occurring at a lower degree of oxygenation than in patients with PAD only, with potential implications for testing, functional staging, and balance disorders.
Keywords: diabetes; exercise tests; near-infrared spectroscopy; pain perception; peripheral arterial disease.
© The Author(s) 2014.