Risk factors for peripheral arterial disease incidence in persons with diabetes: the Atherosclerosis Risk in Communities (ARIC) Study

Some risk factors for peripheral arterial disease (PAD) have been identified, but little information is available on PAD risk factors in individuals with diabetes. Using data from the Atherosclerosis Risk in Communities (ARIC) Study, we assessed the relation of traditional and non-traditional risk factors with the risk of PAD in 1651 participants with diabetes, but not PAD, at baseline. Incident PAD was defined as an ankle–brachial index (ABI) < 0.9 assessed at regular examinations; hospital discharge codes for PAD, amputation, or leg revascularization; or claudication assessed by annual questionnaire. Over a mean of 10.3 years of follow-up, 238 persons developed incident PAD identified, yielding a PAD event rate of 13.9 per 1000 person years. Adjusted for sex, age, race, and center, the risk of developing PAD was increased 1.87-fold (95% confidence interval (95% CI): 1.36–2.57) in persons who were current smokers versus non-smokers, 2.27-fold (95% CI: 1.57–3.26) for baseline coronary heart disease (CHD) versus no baseline CHD, and 1.75-fold (95% CI: 1.18–2.60) for the highest quartile versus lowest quartile of triglycerides. We found no evidence of an association with other blood lipids or hypertension. Compared with the lowest quartiles, comparably-adjusted relative risks for the highest quartiles were 1.60 (95% CI: 1.10–2.33) for waist-to-hip ratio, 2.52 (95% CI: 1.70–3.73) for fibrinogen, 1.70 (95% CI: 1.17–2.47) for factor VIII, 1.73 (95% CI: 1.18–2.54) for von Willebrand factor, 2.15 (95% CI: 1.43–3.24) for white blood cell count, 1.81 (95% CI: 1.19–2.74) for serum creatinine, 0.55 (95% CI: 0.37–0.83) for serum albumin, and 2.73 (95% CI: 1.77–4.22) for carotid intima-media thickness. Persons who had a prior history of diabetes and were taking insulin had a relative risk of 1.97 (95% CI: 1.35–2.87) for future PAD events, compared with those with newly identified diabetes at baseline. In our final multivariable model, current smoking, prevalent CHD, elevated fibrinogen and carotid IMT, and a prior history of diabetes with insulin treatment were independently associated with greater PAD incidence. These markers might be useful to identify individuals with diabetes at particular risk for PAD.