Bone Abstracts

Objectives: Metabolic bone disease of prematurity (MBDP) is a multi-factorial condition characterised by a deficiency of calcium (Ca) and phosphate (PO4) mineral for incorporation into the organic bone matrix. Given the lack of clear guidelines, we conducted a survey across the United Kingdom of current practices, inviting both neonatologists and paediatric metabolic bone disease specialists (PMBS).

Methods: A web-based questionnaire survey was disseminated. Most questions required ticking of the options that applied, but a 5-point Likert scale was used to judge importance of screening and diagnostic tests (1=not important, 5=essential). Responses between neonatologists and PMBS were compared using appropriate statistical tests.

Results: Sixty nine neonatologists responded from 57 neonatal units (30% response rate) and 13 PMBS responded (68% response rate). In both cohorts, serum alkaline phosphatase (ALP) and PO4 were the most utilised investigations for screening and diagnosis. However, much greater emphasis was placed on plasma parathyroid hormone (PTH) in screening and in diagnosis by PMBS (average responses 4.1 and 4.2 respectively) than neonatologists (average responses 1.7 and 1.9 respectively) (P<0.0001 for both screening and diagnosis). Also, greater emphasis was placed on radiograph appearances for diagnosis by MBDS than neonatologists (average response 3.6 vs 2.3 respectively, P=0.003). Ninety-nine percent of neonatologists used PO4 supplements in treating MBDP, with 49% using alfacalcidol, and 28% using Ca supplements. Sixty-two percent of PMBS used PO4 supplements to treat MBDP (P=0.0003), with 54% using Ca supplements and 23% using alfacalcidol. In both cohorts, monitoring of MBDP focussed on serum ALP, PO4 and Ca, but with PMBS more likely to utilise plasma PTH (P<0.0001) and radiograph appearances (P=0.002) also.

Conclusion: Neonatologists treat MBDP using PO4 supplements alone, relying on serum ALP and PO4 for screening and diagnosis. The use of PO4 supplements without consideration of Ca supplements to maintain physiological Ca to PO4 ratios will result in secondary hyperparathyroidism and skeletal demineralisation. Therefore measurement of plasma PTH is an important investigation for screening, diagnosis and monitoring. Alfacalcidol has been introduced into routine practice, without rationale or evidence for benefit. Evidence-based consensus guidelines are needed to standardise safe practice.

Disclosure: The authors declared no competing interests.