Longitudinal Relationship Between Anemia and Statural Growth Impairment in Children and Adolescents With Nonglomerular CKD: Findings From the Chronic Kidney Disease in Children (CKiD) Study.
Academic Article
Overview
abstract
RATIONALE & OBJECTIVE: Anemia and statural growth impairment are both prevalent in children with non-glomerular chronic kidney disease (CKD) and are associated with poor quality of life, and increased morbidity and mortality. However, to date, no longitudinal studies have demonstrated a relationship between anemia and statural growth in this population. STUDY DESIGN: The CKD in Children (CKiD) study is a multicenter prospective cohort study with over 15 years of follow-up. SETTING & PARTICIPANTS: CKiD participants less than 22 years of age with non-glomerular CKD who had not reached final adult height. EXPOSURE: Age-sex-race-specific hemoglobin z-score. OUTCOME: Age-sex-specific height z-score. ANALYTICAL APPROACH: (1) Multivariable repeated measures paired person-visit analysis. (2) Multivariable repeated measures linear mixed model analysis. Both models were adjusted for age, sex, BMI, GFR, acidosis, and medication use. RESULTS: Overall, 67% of the 510 participants studied had declining hemoglobin z-score trajectories over follow-up that included 1763 person-visits. Compared to average hemoglobin z-scores >0, average hemoglobin z-scores of <-1.0 were independently associated with significant growth impairment at the subsequent study visit, with height z-score decline ranging from 0.24 to 0.35. Importantly, in 50% of cases, hemoglobin z-scores of <-1.0 corresponded to hemoglobin values higher than those used as cutoffs defining anemia in the KDIGO guidelines. When stratified by age, the magnitude of the association peaked at 9 years. In line with paired-visit analyses, our mixed model analysis demonstrated that in participants with baseline hemoglobin z-score <-1.0, hemoglobin z-score decline over follow-up was associated with a statistically significant concurrent decrease in height z-score. LIMITATIONS: Limited ability to infer causality. CONCLUSIONS: Hemoglobin decline is associated with growth impairment over time in children with mild to moderate non-glomerular CKD, even before hemoglobin levels reach the cutoffs that are currently used to define anemia in this population.
