Bone Abstracts

Introduction: Bone health in patients with sickle cell disease and thalassemia is impaired. These patients feature altered parameters of bone metabolism and bone mineral density.

Aim and design: To investigate bone health in patients with hemolytic anemia we conducted a cross-sectional analysis in our Hematology Outpatient Clinic at the Children’s Hospital Essen. The largest subgroups within our cohort are patients with homozygous sickle cell (HBSS) disease and patients with spherocytosis.

Clinical and biochemical parameters of growth, puberty, bone turnover, and vitamin D metabolism were obtained, as well as bone densitometry using DXA scans in a subgroup of patients. Additionally a questionnaire was developed assessing life style parameters including calcium and vitamin D intake.

Patients (n=46, 25 females) with the following diagnoses were recruited at regular visits: HBSS disease (n=16), HBSS-α thalassemia (n=1), HBSC disease (n=2), HBS-β thalassemia (n=1), β thalassemia major (n=6), β thalassemia minor (n=1), hereditary spherocytosis (n=14), glucose-6-phosphate deficiency (n=2), paroxysmal nocturnal hemoglobinuria (n=1), and hemolytic anemia of unknown origin (n=2). The study was approved by the Local Ethics Committee.

Results: Mean serum 25-OH vitamin D was 12.0 (1–30.2) ng/ml, BAP was 137.5 (37.3–531.4) U/l, PTH 49.5 (17.3–239.6) pg/ml, N-telopeptide in urine 776.6 (117–1994) mmol/mg creatinine and calcium:creatinine ratio in urine was 0.07 (0.01–0.32) mg/mg.

Vitamin D deficiency (25 OH-vitamin <20 ng/ml) was observed in 78% and secondary hyperparathyroidism in 23%. 19% of patients reported bone pain after physical activity, 12% experienced fractures. Osteopenia (Z-score <−2) was detected in 14% of the patients screened.

No correlation between bone health and markers of disease activity was observed but patients with spherocytosis showed less impairment of bone health than patients with HBSS disease.

Conclusion: Bone health is impaired in patients with hemolytic anemia, especially in children with HBSS disease. Clinically this is reflected by bone pain and/or fractures in some patients. Identification of children at risk is difficult and requires assessment of additional measures. Vitamin D and calcium deficiencies are frequent findings in this group and adequate monitoring and supplementation is recommended.