Low ankle brachial index (ABI) is associated with increases in serum creatinine. 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.
Prospective cohort study.
Setting & Participants
Framingham Offspring cohort participants who attended the sixth (1995-98) and eighth (2005-08) exams.
ABI, categorized as normal (>1.1 to <1.4), low-normal (>0.9 to 1.1), and low (≤0.9).
Rapid eGFR decline (eGFR decline ≥3mL/min/1.73m2 per year), incident stage 3 CKD (eGFR<60mL/min/1.73m2), incident microalbuminuria.
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.
Over 9.5 years, 9.0% (232 of 2592) experienced rapid eGFR decline and 11.1% (270 of 2426) developed stage 3 CKD. Compared to a normal ABI, low ABI was associated with a 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). Among 1902 free of baseline microalbuminuria, low ABI was associated with an 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).
Limited number of events with a low ABI. Outcomes based on single serum creatinine and UACR measurements at each exam.
Low ABI is associated with an increased risk of rapid eGFR decline, suggesting that systemic atherosclerosis predicts decline in kidney function.