Anemia and Growth Impairment in Children With Kidney Disease

Children with nonglomerular chronic kidney disease (CKD) commonly experience anemia and statural growth impairment, associated with poor quality of life and increased morbidity and mortality. According to Oleh Akchurin, MD, PhD, and colleagues there are few data available on the relationship between anemia and statural growth in that patient population.

The researchers reported results from the CKiD (Chronic Kidney Disease in Children) study online in the American Journal of Kidney Diseases [doi.org/1o.1053/j.ajkd.2022.09.019]. CKiD is a multicenter prospective cohort study with more than 15 years of follow-up.

Eligible participants in the current analysis were <22 years of age with nonglomerular CKD who had not reached final adult height. The study exposure was age-sex-race-specific hemoglobin z-score. The primary outcome of interest was age-sex-specific height z-score.

The study utilized multivariable repeated measure in paired person-visit analysis and multivariable repeated measures linear mixed model analysis. Both models were adjusted for age, sex, body mass index, glomerular filtration rate, acidosis, and medication use.

The analysis included 510 patients. Of those, 67% had declining hemoglobin s-score trajectories over follow-up that included 1763 person-visits. Compared with average hemoglobin z-scores ≥0, there was an independent association between average hemoglobin z-scores of <–1.0 and significant growth impairment at the subsequent study visit, and a 0.24 to 0.35 decline in height z-score. In 50% of cases, hemoglobin z-scores of <–1.0 corresponded to hemoglobin values higher than those used as cutoffs defining anemia in the Kidney Disease Improving Global Outcomes guidelines.

When stratified by age, the magnitude of the association peaked at 9 years. In line with paired-visit analyses, the mixed model analysis showed that in participants with baseline hemoglobin z-score <–1.0, there was an association between hemoglobin z-score decline over follow-up and a statistically significant concurrent decrease in height z-score.

The authors noted that the findings were limited by the inability to infer causality.

In summary, the authors said, “Hemoglobin decline is associated with growth impairment over time in children with mild to moderate nonglomerular CKD, even before hemoglobin levels reach the cutoffs that are currently used to define anemia in this population.”