Anemia and low estimated GFR risk factors for chronic kidney disease patients

New research found that severe anemia, low iron levels, and low estimated glomerular filtration rates are the risk factors for chronic kidney disease patients along with several adverse outcomes. The study was published in the American Journal of Kidney Diseases. 

Anemia in chronic kidney disease (CKD) is common and has unfavorable results. There are no currently available ideal treatments for anemia in CKD. So, researchers conducted a cross-sectional prospective cohort study to characterize the burden, risk factors for, and risks associated with anemia by estimated glomerular filtration rate (eGFR) and hemoglobin level in CKD. 

From the Optum Labs Data Warehouse outpatient data of 5,004,957 individuals across 57 healthcare centers in the US was collected from 2016 to 2019. The prevalence of anemia, low iron test results, vitamin B12 deficiency, and erythropoiesis-stimulating agent (ESA) use, stratified by sex and eGFR, were characterized. The main outcomes of measurement were the incident end-stage kidney disease, cardiovascular disease, coronary heart disease, stroke, heart failure, and death. Polychotomous logistic regression was used to estimate adjusted odds ratios of different hemoglobin levels across eGFR. Cox proportional hazards regression was used to calculate adjusted hazard ratios for adverse outcomes across hemoglobin levels. 

Findings: 

• The mean age of the participants was 54 years and out of the total 42% were male.
• After adjustment, it was found that lower eGFR was very strongly associated with an increased prevalence of anemia.
• Despite checking iron studies less frequently in anemic patients, low iron test results were highly prevalent in those tested. 
• 60.4% of men and 81.3% of women showed low iron levels.
• Only <4% of the participants used the Erythropoiesis-stimulating agent.
• Lower hemoglobin was independently associated with an increased risk of end-stage kidney disease, cardiovascular disease, coronary heart disease, stroke, heart failure, and death. 

Despite some limitations of the study like reliance on ICD codes for medical diagnoses, and obtaining death information from claims data, this observational study showed that severe anemia was common and strongly associated with lower eGFR and multiple adverse outcomes, and low iron test results were highly prevalent along with less usage of Erythropoiesis-stimulating agent. 

Further reading: https://doi.org/10.1053/j.ajkd.2022.07.014 

Farrington DK, Sang Y, Grams ME, Ballew SH, Dunning S, Stempniewicz N, Coresh J. Anemia Prevalence, Type, and Associated Risks in a Cohort of 5.0 Million Insured Patients in the United States by Level of Kidney Function. Am J Kidney Dis. 2022 Sep 23:S0272-6386(22)00914-3.