Low ankle-brachial index and the development of rapid estimated GFR decline and CKD.
BACKGROUND
Low ankle-brachial index (ABI) is associated with increases in serum creatinine level. Whether low ABI is associated with the development of rapid estimated glomerular filtration rate (eGFR) decline, stage 3 chronic kidney disease (CKD), or microalbuminuria is uncertain.


METHODS
Prospective cohort study.


METHODS
Framingham Offspring cohort participants who attended the sixth (1995-1998) and eighth (2005-2008) examinations.


METHODS
ABI, categorized as normal (>1.1 to <1.4), low-normal (>0.9 to 1.1), and low (≤0.9).


RESULTS
Rapid eGFR decline (eGFR decline ≥3 mL/min/1.73 m(2) per year), incident stage 3 CKD (eGFR <60 mL/min/1.73 m(2)), incident microalbuminuria.


METHODS
GFR was estimated using the serum creatinine-based CKD-EPI (CKD Epidemiology Collaboration) equation. Urinary albumin-creatinine ratio (UACR) was determined based on spot urine samples.


RESULTS
During 9.5 years, 9.0% (232 of 2,592) experienced rapid eGFR decline and 11.1% (270 of 2,426) developed stage 3 CKD. Compared to normal ABI, low ABI was associated with 5.73-fold increased odds of rapid eGFR decline (95% CI, 2.77-11.85; P<0.001) after age, sex, and baseline eGFR adjustment; this persisted after multivariable adjustment for standard CKD risk factors (OR, 3.60; 95% CI, 1.65-7.87; P = 0.001). After adjustment for age, sex, and baseline eGFR, low ABI was associated with a 2.51-fold increased odds of stage 3 CKD (OR, 2.51; 95% CI, 1.16-5.44; P = 0.02), although this was attenuated after multivariable adjustment (OR, 1.68; 95% CI, 0.75-3.76; P = 0.2). In 1,902 free of baseline microalbuminuria, low ABI was associated with increased odds of microalbuminuria after adjustment for age, sex, and baseline UACR (OR, 2.81; 95% CI, 1.07-7.37; P = 0.04), with attenuation upon further adjustment (OR, 1.88; P = 0.1).


CONCLUSIONS
Limited number of events with low ABI. Outcomes based on single serum creatinine and UACR measurements at each examination.


CONCLUSIONS
Low ABI is associated with an increased risk of rapid eGFR decline, suggesting that systemic atherosclerosis predicts a decrease in kidney function.
National Heart, Lung, and Blood Institute's (NHLBI's) Framingham Heart Study, Framingham, MA, USA.
Meredith C
MC
Foster
Nimrta
N
Ghuman
Shih-Jen
SJ
Hwang
Joanne M
JM
Murabito
Caroline S
CS
Fox
D000368:Aged; D055109:Ankle Brachial Index; D015331:Cohort Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors