High Prevalence of Peripheral Arterial Disease but Low Antiplatelet Treatment Rates in Elderly Primary Care Patients With Diabetes

Although diabetes is primarily a metabolic disorder, it is also a vascular disease (1). We aimed to determine the prevalence of peripheral arterial disease (PAD), comorbidity of atherothrombotic manifestations, and antiplatelet treatment intensity among elderly diabetic patients in primary care, as previous studies usually investigated smaller and highly selected samples.

In this cross-sectional study, 344 general practitioners throughout Germany determined the ankle-brachial index (ABI) of 6,880 consecutive, unselected patients aged ≥65 years with bilateral Doppler ultrasound measurements (2). PAD was defined as ABI <0.9, or peripheral revascularization, or amputation because of PAD. Additionally, the World Health Organization questionnaire on intermittent claudication was used to assess symptomatic PAD. Coronary artery disease (CAD) events (infarction or revascularization of coronary vessels) and cerebrovascular disease (CVD) events (stroke or revascularization of carotids) were taken from the patient’s history. Diabetes was defined according to the clinical diagnosis of the physician, and/or HbA_1c ≥6.5%, and/or intake of oral antidiabetic medication, and/or application of insulin.

There were 1,743 patients classified as having diabetes; the median disease duration was 6 years (1st and 3rd quartile: 2, 11), median HbA_1c 6.6% (5.9, 7.3), mean age 72.5 ± 5.4 years, and 51.4% were women. Patients with diabetes had, in comparison with nondiabetic subjects, a higher prevalence of PAD, defined as ABI <0.9 (26.3 vs.15.3%, univariate odds ratio [OR] 2.0 [95% CI: 1.7–2.3]), intermittent claudication (5.1 vs. 2.1%, OR 2.5 [1.9–3.4]), CAD events (16.1 vs. 10.6%, OR 1.6 [1.4–1.9]), and CVD events (6.8 vs. 4.8%, OR 1.4 [1.2–1.8]).

Only 57.4% of the diabetic patients with previously known PAD (as the only atherothrombotic manifestation) received antiplatelet therapy with aspirin, clopidogrel, or ticlopidine (which was similar to nondiabetic patients, 54.4%; P = 0.63). If only CAD and/or CVD were present, the treatment rates were 75.1% for diabetic patients and 72.8% for nondiabetic patients (P = 0.51), and if CAD and/or CVD were present in addition to PAD, rates were 81.8% for diabetic patients and 80.7% for nondiabetic patients (P = 0.87).

Elderly patients with diabetes had an increased risk for PAD and CAD and CVD events compared with nondiabetic patients. However, the risk of PAD in diabetic subjects was substantially higher than for one of the other atherothrombotic manifestations. In terms of antiplatelet treatment, no difference was found between diabetic and nondiabetic patients. In addition, despite the well-established benefits of antiplatelet therapy in high-risk groups (3), patients with PAD were less intensively treated than patients with CAD. In accordance with current guidelines, efforts should be made to substantially intensify secondary prevention with antiplatelet therapy in patients with symptomatic or asymptomatic PAD (4).