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 2023;
81:201-209.e1. [PMID:
36181996 PMCID:
PMC9868077 DOI:
10.1053/j.ajkd.2022.07.014]
[Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 07/28/2022] [Indexed: 01/26/2023]
Abstract
RATIONALE & OBJECTIVE
Anemia is common in chronic kidney disease (CKD); although anemia is associated with adverse outcomes, the available treatments are not ideal. We characterized the burden, risk factors for, and risks associated with anemia by estimated glomerular filtration rate (eGFR) and hemoglobin level.
STUDY DESIGN
Cross-sectional and prospective cohort study.
SETTING & PARTICIPANTS
Outpatient data from 5,004,957 individuals across 57 health care centers in the United States from 2016 to 2019, extracted from the Optum Labs Data Warehouse.
EXPOSURE
Severity of anemia, presence of low iron test results, eGFR.
OUTCOME
Incident kidney failure with replacement therapy, cardiovascular disease, coronary heart disease, stroke, heart failure, death.
ANALYTICAL APPROACH
The prevalences of anemia, low iron test results, vitamin B12 deficiency, and erythropoiesis-stimulating agent (ESA) use, stratified by sex and eGFR, were characterized. Polychotomous logistic regression was used to estimate the 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 level.
RESULTS
The mean age was 54 years, and 42% were male. Lower eGFR was very strongly associated with increased prevalence of anemia, even after adjustment. Although iron studies were checked infrequently in patients with anemia, low iron test results were highly prevalent in those tested: 60.4% and 81.3% of men and women, respectively. ESA use was uncommon, with a prevalence of use of<4%. Lower hemoglobin was independently associated with increased risk of incident kidney failure with replacement therapy, cardiovascular disease, coronary heart disease, stroke, heart failure, and death.
LIMITATIONS
Reliance on ICD codes for medical diagnoses, death information obtained from claims data, observational study.
CONCLUSIONS
Severe anemia was common and strongly associated with lower eGFR and multiple adverse outcomes. Low-iron test results were highly prevalent in those tested despite iron studies being checked infrequently. ESA use in nondialysis CKD patients was uncommon.
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