Abstract
Background Paediatric patients with chronic kidney disease are known to have an increased risk of fracture. However, data pertaining to children with end stage kidney disease (ESKD) receiving renal replacement therapy (RRT) is limited.
Objectives The aim of this study is to determine the incidence of fracture and associated factors in this specific group of patients.
Methods We conducted a retrospective review on all paediatric patients with ESKD at the tertiary Paediatric Nephrology Centre in Hong Kong. Children who presented before 18 years with active follow-ups for 12 or more months by November 2020 were included.
Results RRT was initiated in 69 children (55% boys) at a mean age of 9.2 ±5.9 years. At the time of evaluation, 21 (30.4%), 10 (14.5%) and 38 (55.1%) patients received peritoneal dialysis (PD), haemodialysis (HD) and kidney transplant respectively. 3 patients (4.3%) had prior kidney graft loss and resumed on dialysis. One patient (1.5%) reported a fracture prior to RRT.
Over a median of 5.2 years (IQR 3.0–8.3) follow-up, 10 fracture episodes were observed in 7 patients (10.1%) at a mean duration of 7.8 ±8 years since RRT initiation, corresponding to a cumulative fracture incidence of 227.8 per 10000 patient year (95% CI, 86.6–369.0). This rate was 5-folds higher than published data from our local general paediatric population (45 per 10,000 person-years; 95% CI, 43.9–46.1; p=0.01). Of note, all patients experienced single fracture episode except one child who developed 4 fracture episodes.
Children who sustained fractures were significantly younger at the time of RRT initiation (3.5 vs 10.4 years; p=0.02) and had a longer time on dialysis (12 vs 2.7 years; p<0.001). Other factors associated with fractures included metabolic bone disease (28.6% versus 1.6%; p=0.03), difficulty in walking (28.6% versus 3.2%; p=0.05), radiological evidence of renal osteodystrophy (85.7% vs 25.8%; p=0.003), parathyroid hyperplasia/adenoma (100% vs 31.8%; p=0.01) and a higher parathyroid hormone level (pmol/L) (62.7 vs 30.3; p=0.02). Calcium, phosphate and ALP levels, as well as the proportion of patients with vitamin D deficiency were similar between the two groups. While the practice of native and active vitamin D and phosphate binders were not different, more patients with fracture received cinacalcet (57.1% versus 12.9%; p=0.02), which may suggest more severe hyperparathyroidism.
Conclusions Children with ESKD receiving RRT are at a higher risk of fracture. Longer duration of dialysis and a higher average parathyroid hormone level were potential modifiable factors associated with fractures.
