Cross-validated calculation procedure to assess the cholecalciferol loading dose for rapid correction of vitamin D deficiency
Lenneke van Groningen, Adriaan van Sorge, Darryl Telting, Astrid Giessen & Hans de Boer
Introduction: Vitamin D deficiency is very common in Northern Europe. Recently, we developed an equation to calculate the vitamin D deficit, based on the serum 25-OH vitamin D3 (25OHD3) level and body weight: vitamin D deficit (IU)=40×(75−serum 25OHD3)×body weight. The calculated deficit gives the amount of cholecalciferol that is required to raise the serum 25OHD3 level to the target of 75 nmol/l.
Objective: To cross-validate the vitamin D deficit calculation procedure.
Materials and methods: Fifty subjects (age range 2474 years, female/male ratio 2.8:1, body weight 45230 kg) with vitamin D deficiency (defined as a serum vitamin D < 50 nmol/l) were treated with oral, solubilised CholecalciferolFNA 50.000 IE three times a week until the calculated cumulative dose was reached. Serum creatinine, phosphate, albumin, PTH, 25OHD3 were measured at baseline and 10 days after the final dose of cholecalciferol.
Results:: Of 78% had severe vitamin D deficiency (25OHD3 <30 nmol/l). The calculated cumulative dose ranged from 75.000300.000 IU. Treatment was completed within 2 weeks in all patients. Mean serum 25OHD3 increased from 26.4±11.8 to 76.7±21.4 nmol/l (mean±S.D). Ninety percent of the patients reached a serum 25OHD3 >50 nmol/l. Vitamin D intoxication, defined as a serum level >220 nmol/l, was not observed. The highest post-treatment level was 148 nmol/l. Serum creatinine increased slightly, whereas serum calcium, phosphate, albumin and PTH levels did not change significantly.
Conclusion: The equation predicting the cholecalciferol loading dose required for rapid correction of vitamin D deficiency is effective and can be safely used in daily practice.