Subclinical peripheral arterial disease in patients with chronic kidney disease: prevalence and related risk factors.

BACKGROUND: Atherosclerotic artery disease is a common condition in patients with chronic kidney disease (CKD); however, there are few published data on the prevalence of peripheral arterial disease (PAD) in nondialyzed patients with renal insufficiency. The ankle-brachial index (ABI) is a simple, noninvasive, and reliable method to assess PAD. METHODS AND
RESULTS: Prevalence of PAD using ABI was investigated in 102 patients referred for the first time to a nephrology clinic with CKD in stages 3 to 5 of the K/DOQI classification, and with no previous diagnosis of PAD. Patients with ABI <0.9 were considered positive for PAD. A total of 64% of the patients were male. The mean age was 70 +/- 11 (range 58-84) years, and the estimated creatinine clearance (CrCl) was 35 +/- 12 (range 6-59) mL/min(-1). Of the total sample, 26% were diabetics, 10% active smokers, 48% ex-smokers, and 29% had a diagnosis of coronary heart disease (CHD), 15% had been previously diagnosed of stroke, and 17% had signs and symptoms compatible with intermittent claudication, which had passed unnoticed. Thirty-two percent of patients had an ABI <0.9 (mean 0.64 +/- 0.25). Of these patients with PAD, 84% were men (P < 0.005), and only 30% presented a clinical picture compatible with intermittent claudication. Absolute risk of CHD according to the Framingham 1998 score was higher in the PAD group (19.3% +/- 6 vs. 13.1% +/- 8; P= 0.01). Patients with PAD were older (75 +/- 6 vs. 66 +/- 11 years, P= 0.000), and had worse renal function (CrCl 30.8 +/- 12 vs. 37 +/- 10.7 mL.min(-1), P= 0.016) compared to patients without PAD, but no differences were found in cholesterol levels (total, HDL, LDL), calcium, phosphorus, or PTH. In the logistic regression analysis, independent indicators of PAD risk were male sex, age, and lower CrCl. Twelve percent of patients had an ABI > or =1.3, suggestive of parietal arterial calcifications. In these patients, systolic blood pressure and pulse pressure were lower (126 +/- 18 vs. 150 +/- 27, P= 0.005, and 52 +/- 13 vs. 68 +/- 25 mm Hg, P= 0.044), i-PTH levels were higher (228 +/- 267 vs. 117 +/- 63 pg/mL, P= 0.01), and a larger proportion of this group was treated with calcitriol (34% vs. 13%) compared to patients with a normal ABI.
CONCLUSION: A high prevalence of PAD, considered as an ABI <0.9, was demonstrated in nondialyzed patients with CKD. This was related with age, male sex, and higher degree of renal insufficiency, while the presence of ABI > or =1.3 was associated with a greater degree of hyperparathyroidism. These data show the need to carry out routine ABI determinations in patients with CKD for early detection of peripheral arterial disease.