title: Elevated Blood Urea Nitrogen is Associated With Critical Limb Ischemia in Peripheral Arterial Disease Patients.
abstract: As renal function is often impaired in atherosclerosis patients, accelerating atherosclerosis per se and creating a vicious cycle, we investigated the association of blood urea nitrogen (BUN) and critical limb ischemia (CLI) in peripheral arterial occlusive disease (PAOD) patients. Our cross-sectional study included 1521 PAOD patients, with normal and impaired renal function treated at our institution from 2005 to 2010. Patients on renal replacement therapy were excluded. The cohort was divided into tertiles according to the serum BUN levels. An optimal cutoff value for the continuous BUN was calculated by applying a receiver-operating curve analysis to discriminate between CLI and non-CLI. In our cohort, CLI increased significantly with an increase in BUN (13.1% in the first tertile, 18.7% in the second tertile, 29.0% in the third tertile, P for trend < 0.001). A BUN of 17.7  mg/dL was identified as an optimal cutoff. Accordingly, there were 2 groups of patients: 636 patients with BUN ≤ 17.7 and 885 patients with BUN > 17.7. CLI was more frequent in BUN > 17.7 patients (342 [38.6%]) than in BUN  ≤ 17.7 patients (134 [21.1%]) (P < 0.001); the same applied to prior myocardial infarction (45 [5.1%] vs 15 [2.4%], P = 0.007) and congestive heart failure (86 [9.7%] vs 31 [4.9%], P < 0.001). A BUN > 17.7 was associated with an odds ratio of 1.6 (95% confidence interval: 1.3-1.9, P < 0.001) for CLI even after the adjustment for other established vascular risk factors such as age ≥ 75 and type 2 diabetes. An increased BUN is significantly associated with a high risk for CLI and other vascular endpoints. The BUN is an easily determinable, broadly available, and inexpensive marker that could be used to identify patients at high risk for vascular endpoints.
authors.affiliation: From the Division of Angiology (TG, FH, GH, PR, PE, MB); Division of Oncology (MP); and Division of Nephrology (GS), Department of Internal Medicine, Medical University Graz, Graz, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Gary
authors.forename: Martin
authors.initials: M
authors.lastname: Pichler
authors.forename: Gernot
authors.initials: G
authors.lastname: Schilcher
authors.forename: Franz
authors.initials: F
authors.lastname: Hafner
authors.forename: Gerald
authors.initials: G
authors.lastname: Hackl
authors.forename: Peter
authors.initials: P
authors.lastname: Rief
authors.forename: Philipp
authors.initials: P
authors.lastname: Eller
authors.forename: Marianne
authors.initials: M
authors.lastname: Brodmann
mesh_terms: D000367:Age Factors; D000368:Aged; D015415:Biomarkers; D001806:Blood Urea Nitrogen; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D005121:Extremities / Q000098:blood supply*; D005260:Female; D006801:Humans; D007511:Ischemia / Q000097:blood* / Q000453:epidemiology*; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D058729:Peripheral Arterial Disease / Q000097:blood* / Q000453:epidemiology*; D051437:Renal Insufficiency; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D015415:Biomarkers