Diabetes and Claudication: Reduced Pain Perception; Worse Walking Impairment, and Quality of Life

The effects of diabetes in patients with peripheral artery disease (PAD) who present with claudication are poorly defined. Given the association of diabetes with increased risk for accelerated atherogenesis and poor vascular outcomes, we hypothesized that claudicating patients with diabetes would display worse clinical and physiological characteristics including angiographic disease distribution, physiology of oxygen delivery, walking ability, at home physical activity (HPA), and quality of life (QoL) than claudicating patients without diabetes. We performed a comparison of demographics, comorbidities, physiological testing outcomes, and QoL survey in claudicating patients with diabetes (HbA1c >6.5%) and without diabetes (HbA1C < 6.5%). The patients underwent evaluation of CT angiography (CTA), ankle brachial indices (ABIs), and 6-minute walking distance (6MWD). They also performed a treadmill test for measurement of initial (ICD) and maximal claudication walking distance (MCD), coupled with calf muscle oximetry measurements (STO2) with near infrared spectroscopy, and measurement of the recovery time from claudication pain (RT) after completion of treadmill testing. Patients also completed a 36-item Short Form QoL (SF36) questionnaire and had their HPA measured using a pedometer for 7 days. The diabetic group (n = 15) had higher BMI (31.1 ± 6.8 vs 26.4 ± 4.4 kg/m2; P < .01), and a higher rate of hyperlipidemia (93% vs 72%; P < .01) than the non-diabetic group (n = 61). There were no differences in ABI, CTA, MCD, and STO2 parameters. There were longer ICD (208.2 ± 33.7 vs 124.0 ± 94.5 meters; P < .02) and shorter RT in the diabetic patients (287.4 ± 234.8 vs 133.9 ± 126 seconds; P < .005). The diabetes group, on the other hand, demonstrated shorter 6MWD (252.3 ± 62.3 vs 298.4 ± 60.2 meters; P < .02), had 50% (P < .005) decrease in HPA, and performed significantly worse on measures of social functioning, emotional well-being, energy, and fatigue in the SF36 questionnaire (P < .05). Diabetic and non-diabetic claudicating patients had similar angiographic disease distribution, maximal claudication distances, and physiology of oxygen delivery to their calf muscles during walking. However, diabetics had longer ICDs, and shorter RTs pointing to significant alterations in pain perception and the pain pathways of the legs. They also had decreased HPA and 6MWD with worse QoL measures, suggesting that diabetes predisposes to worse walking outcomes and QoL in patients with PAD. Our findings provide a rare insight into the interaction between diabetes and PAD and merit further research. Identification and aggressive management of PAD should be given priority in diabetics as presenting symptoms may be milder despite worse impairment and QoL.