title: Factors influencing pathological ankle-brachial index values along the chronic kidney disease spectrum: the NEFRONA study.
abstract: The ankle-brachial index (ABI) is widely used to diagnose subclinical peripheral artery disease (PAD) in the general population, but data assessing its prevalence and related factors in different chronic kidney disease (CKD) stages are scarce. The aim of this study is to evaluate the prevalence and associated factors of pathological ABI values in CKD patients.
  
  
  
  NEFRONA is a multicentre prospective project that included 2445 CKD patients from 81 centres and 559 non-CKD subjects from 9 primary care centres across Spain. A trained team collected clinical and laboratory data, performed vascular ultrasounds and measured the ABI.
  
  
  
  PAD prevalence was higher in CKD than in controls (28.0 versus 12.3%, P < 0.001). Prevalence increased in more advanced CKD stages, due to more patients with an ABI ≥1.4, rather than ≤0.9. Diabetes was the only factor predicting both pathological values in all CKD stages. Age, female sex, carotid plaques, higher carotid intima-media thickness, higher high-sensitivity C-reactive protein (hsCRP) and triglycerides, and lower 25-hydroxi-vitamin D were independently associated with an ABI ≤0.9. Higher phosphate and hsCRP, lower low-density lipoprotein (LDL)-cholesterol and dialysis were associated with an ABI ≥1.4. A stratified analysis showed different associated factors in each CKD stage, with phosphate being especially important in earlier CKD, and LDL-cholesterol being an independent predictor only in Sage 5D CKD.
  
  
  
  Asymptomatic PAD is very prevalent in all CKD stages, but factors related to a low or high pathological ABI differ, revealing different pathogenic pathways. Diabetes, dyslipidaemia, inflammation and mineral-bone disorders play a role in the appearance of PAD in CKD.
authors.affiliation: Nephrology Department, Hospital Universitari Arnau de Vilanova, Lleida, Spain.|Unit for Detection and Treatment of Atherotrombotic Disease (UDETMA), Nephrology Department, Hospital Universitari Arnau de Vilanova, Lleida, Spain.|Experimental Nephrology Laboratory, IRB-Lleida, Hospital Universitari Arnau de Vilanova, Lleida, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Arroyo
authors.affiliation: Nephrology Department, Hospital Universitari Arnau de Vilanova, Lleida, Spain.|Unit for Detection and Treatment of Atherotrombotic Disease (UDETMA), Nephrology Department, Hospital Universitari Arnau de Vilanova, Lleida, Spain.
authors.forename: Angels
authors.initials: A
authors.lastname: Betriu
authors.affiliation: Biostatistics Unit, IRB-Lleida, Hospital Universitari Arnau de Vilanova, Lleida, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Valls
authors.affiliation: Nephrology Department, Hospital Universitario Doctor Peset, Valencia, Spain and.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Gorriz
authors.affiliation: Unidad de Vigilancia de la Salud, Unión de Mutuas, Medicine Department, Universitat Jaume I, Castellón, Spain.
authors.forename: Vicente
authors.initials: V
authors.lastname: Pallares
authors.affiliation: Experimental Nephrology Laboratory, IRB-Lleida, Hospital Universitari Arnau de Vilanova, Lleida, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Abajo
authors.affiliation: Experimental Nephrology Laboratory, IRB-Lleida, Hospital Universitari Arnau de Vilanova, Lleida, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Gracia
authors.affiliation: Experimental Nephrology Laboratory, IRB-Lleida, Hospital Universitari Arnau de Vilanova, Lleida, Spain.
authors.forename: Jose Manuel
authors.initials: JM
authors.lastname: Valdivielso
authors.affiliation: Nephrology Department, Hospital Universitari Arnau de Vilanova, Lleida, Spain.|Unit for Detection and Treatment of Atherotrombotic Disease (UDETMA), Nephrology Department, Hospital Universitari Arnau de Vilanova, Lleida, Spain.|Experimental Nephrology Laboratory, IRB-Lleida, Hospital Universitari Arnau de Vilanova, Lleida, Spain.
authors.forename: Elvira
authors.initials: E
authors.lastname: Fernandez
mesh_terms: D000368:Aged; D055109:Ankle Brachial Index; D002097:C-Reactive Protein / Q000378:metabolism; D059168:Carotid Intima-Media Thickness; D008078:Cholesterol, LDL / Q000097:blood; D015331:Cohort Studies; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000453:epidemiology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D058729:Peripheral Arterial Disease / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D011446:Prospective Studies; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology*; D012307:Risk Factors; D012720:Severity of Illness Index; D013030:Spain / Q000453:epidemiology; D014280:Triglycerides / Q000097:blood; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D008078:Cholesterol, LDL; D014280:Triglycerides; D014807:Vitamin D; D002097:C-Reactive Protein; C104450:25-hydroxyvitamin D
keywords: ankle-brachial index; atheromatosis; cardiovascular risk; chronic kidney disease; peripheral artery disease