Endocrine Abstracts

In our institution, an observed loading dose of oral colecalciferol (D3) 300 000 units is used for treatment of vitamin D deficiency (Vit D <30 nmol/l), with subsequent re-evaluation at 6 weeks and 3 months. We evaluated the follow-up of all the patients who received loading dose colecalciferol against adherence to this protocol.

Method: All patients who received observed loading dose of colecalciferol for a 1-year period were included. Demographic, clinical, and biochemical data was collected from existing databases and clinical notes.

Results: A total of 256 patients had observed loading dose colecalciferol (female 179 and male 77). The age range was 18–91 years old. The median age was 54.62 years. Basal Vit D at time of loading ranged between <20 and 43.5 nmol/l.

Vit D was repeated at 6 weeks and 3 months, as per protocol in only 63 and 48% of cases respectively. Of those who did have Vit D rechecked at 6 weeks, 87% (n=140/161) improved their Vit D concentration >50 nmol/L, 9.3% (n=15) had levels between 20–50 nmol/l and only 3.7% (n=6) had Vit D <20 nmol/l. Vitamin D concentrations fell to <50 nmol/l in 48% (74/154) of the patients within 12 months.

18.75% (n=48) patients required oral reloading within 12 months and seven were switched to i.m. ergocalciferol. Four of these patients were known to have malabsorption problems. There was no correlation between BMI and the response to high dose Vit D or need for further oral reloading. There were no episodes of toxicity or adverse events. There was no significant hypercalcaemia.

Conclusion: Observed loading dose colecalciferol was safe and efficacious in this heterogeneous group of patients. Problems with adherence to the protocol were identified which led to need for reloading in a large group of patients. BMI had no impact on response to high dose Vit D.