Bone Abstracts

Objectives: Haemophilia A (FVIII deficiency) is an X-linked disorder of haemostasis with bleeding tendency, mainly in joints and muscles. Recurrent haemarthroses, subsequent immobilization and avoidance of contact sports, may affect these patients’ skeletal health.

Methods: Evaluation of bone health was performed in 51 children with Haemophilia A (severe: 41, all on prophylaxis treatment), mean age: 11.7±3.6 years. Dual-energy X-Ray absorptiometry (DXA) of total body less head (TB) and lumbar spine (LS) was performed. Also, laboratory markers for bone formation (boneALP, osteocalcin, type I procollagen carboxy-terminal propeptide (PICP)) and bone resorption (urinary deoxypyridinoline/creatinine (uDPD/uCr), urinary calcium excretion (uCa/uCr), tartrate-resistant acid phosphatase (boneTRAP5b)) as well as vitamin D (25-OH-D) and PTH were measured.

Results: Mean LS bone mineral density (BMD) Z-score was −0.51±0.98 (10% with low Z-score ≤ −2, 20% with low-normal Z-score, i.e. between −1 and −2). Mean TB BMD Z-score was 0.18±0.85 (9.1% with low-normal Z-score). Compared to the laboratory reference values, octeocalcin was significantly lower (19.06±5.8 ng/ml, p<0.05), whereas the other bone formation markers were normal. Moreover, osteocalcin was positively but weakly correlated with LS and TB BMD Z-scores (r=0.337 and r=0.313 respectively, p<0.05). Increased uDPD/uCr (mean value 32.35±14.6 mmol/mmol) was found in 77.6% of the patients and it was negatively and strongly correlated to both LS and TB BMD Z-scores (r=−0.677, −0.569 respectively, p<0.01). Patients with increased uDPD/uCr had lower LS BMD Z-scores (−0.82±0.85 vs −0.20±0.97, p<0.05) and TB BMD Z-scores (mean −0.08±0.69 vs −0.37±0.91, p<0.05). No significant differences were detected in uCa/uCr and boneTRAP5b. Low vitamin D levels (mean 27.9±19.33 ng/ml, normal values >20 ng/ml) were found in 36.7% of the patients and there was no correlation with BMD.

Conclusions: In our study, lumbar BMD was more severely affected than TB BMD and bone metabolism was also disturbed, with more significant changes in bone resorption. This is important for prompt detection of patients at risk, as metabolic bone markers tend to change earlier than BMD. Finally, one in three patients had vitamin D deficiency. Taken together, these results emphasize the negative impact of haemophilia A on bone health and underline the need for close surveillance of this population.

Disclosure: The authors declared no competing interests.