Background:
Both chronic kidney disease (CKD) measures, estimated glomerular filtration rate (eGFR) and albumin-to-creatinine ratio (ACR), are associated with incident heart failure (HF). Anemia is thought to play an important role in this association, particularly when eGFR is reduced, but this concept has not been rigorously evaluated.
Methods:
Using data from 5,539 participants in the Atherosclerosis Risk in Communities (ARIC) study at the fourth visit (1996-98), we first assessed the prevalence ratio (PrR) of anemia for eGFR and ACR using cross-sectional Poisson models, and then prospectively quantified the associations of eGFR, ACR, and anemia with incident HF using Cox proportional hazard models.
Results:
Based on the WHO definition, 477 (8.6%) participants had anemia at baseline. Both CKD measures were associated with increased prevalence of anemia independently of each other and other potential confounders (PrR, 1.22 [95% confidence interval, 1.11-1.34] with every 1SD decrease in eGFR; and 1.12 [1.03-1.23] with every 1SD increase in log
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ACR). There were 724 (13.1%) cases of incident HF over median follow-up of 14.8 years. Lower eGFR and higher ACR were independently associated with increased risk of HF regardless of anemia status (Figure A for eGFR, and B for ACR). The association between anemia and HF risk was generally consistent in the range of eGFR below 90 ml/min/1.73m
2
and ACR between 5 and 300 mg/g, without significant interaction between both CKD measures and anemic status (e.g., hazard ratio for anemia vs. no anemia: 1.40 [0.81-2.41] at eGFR 60 ml/min/1.73m
2
and 1.37 [0.67-2.80] at ACR 30 mg/g).
Conclusions:
Reduced eGFR and elevated ACR were independently associated with higher prevalence of anemia and HF risk. The contribution of anemia to HF risk was overall consistent across CKD ranges of eGFR and ACR. Our results suggest the need of clinical attention on anemia and related HF risk in persons with low eGFR as well as those with high ACR.
Adjusting for reverse causation to estimate the effect of obesity on mortality after incident heart failure in the Atherosclerosis Risk in Communities (ARIC) study
