Ankle-brachial index predicts renal outcomes and all-cause mortality in high cardiovascular risk population: a nationwide prospective cohort study in CORE project.

BACKGROUND: Low ankle-brachial index (ABI) related ischemic events are common among individuals with chronic kidney disease (CKD). It is also associated with an increased risk of rapid renal function decline. The presence of peripheral artery disease (PAD) with low ABI among patients with high cardiovascular (CV) risk increases limb loss and mortality.

AIMS: To estimate the association between abnormal ABI and renal endpoints and all-cause mortality.

METHODS: A multicenter prospective cohort study was conducted among subjects with high CV risk or established CV diseases in Thailand. The subjects were divided into 3 groups based on ABI at baseline > 1.3, 0.91-1.3, and ≤ 0.9, respectively. Primary composite outcome consisted of estimated glomerular filtration rate (eGFR) decline over 40%, eGFR less than 15 mL/min/1.73 m2 , doubling of serum creatinine and initiation of dialysis. The secondary outcome was all-cause mortality. Cox regression analysis and Kaplan-Meier curve were performed.

RESULTS: A total of 5543 subjects (3005 men and 2538 women) were included. Cox proportional hazards model showed a significant relationship of low ABI (ABI ≤ 0.9) and primary composite outcome and all-cause mortality. Compared with the normal ABI group (ABI 0.91-1.3), subjects with low ABI at baseline significantly had 1.42-fold (95% CI 1.02-1.97) and 2.03-fold (95% CI 1.32-3.13) risk for the primary composite outcome and all-cause mortality, respectively, after adjusting for variable factors.

CONCLUSION: Our study suggested that PAD independently predicts the incidence of renal progression and all-cause mortality among Thai patients with high CV risk.