Evaluation of Bone Mineral Density in Children with Chronic Kidney Disease

Abstract

Mineral and bone disorder (MBD) is a frequent complication in patients with chronic kidney disease (CKD). Renal replacement therapy has been shown to extend the life expectancy of patients with CKD, resulting in MBD becoming a major cause of morbidity. The aim of our study was to evaluate bone mineral density (BMD) in patients under follow-up for CKD. Seventy-one pediatric patients diagnosed with CKD and followed up were included in this retrospective cross-sectional study. Demographic, clinical, and laboratory data, treatment histories, and BMD measures of the lumbar spine (L1-L4) obtained using dual-energy X-ray absorptiometry were retrospectively collected from medical records. The mean age of the patients was 13.1±2.9 years; 62.0% were female. Growth impairment was common, with median height and weight standard deviation scores of -1.88 (minimum-maximum: -8.66 to 0.63) and -1.93 (minimum-maximum: -7.66 to 5.27), respectively. Most patients were pubertal (70.4%), and delayed skeletal maturation was observed, with a median bone age of 12.0 years (minimum-maximum: 4.0-19.0). The cohort included patients across all CKD stages, with 53.6% in stages 4-5 and 40.8% receiving dialysis. Mean areal BMD was 0.802±0.175 g/cm²; height-adjusted and bone-age–adjusted BMD Z-scores were 2.27±1.73 and 1.15±1.90, respectively. In univariate logistic regression analysis, a lower bone age–adjusted BMD Z-score [odds ratio (OR)=0.666, 95% confidence interval (CI)=0.458-0.971] and a low physical activity level (OR=5.556, 95% CI=1.461-21.126) were significantly associated with increased fracture risk. These findings indicate that growth impairment and delayed skeletal maturation substantially affect BMD assessment in pediatric CKD. Bone age-adjusted BMD Z-scores and low physical activity levels appear to be important determinants of fracture risk, highlighting the need for a more comprehensive approach to bone health evaluation in this population.