HCP vitamin D resources:


Clinical Knowledge Summaries (CKS)19 published by NICE on the treatment and prevention of vitamin D deficiency in adults and children provide practical clinical guidance to support HCPs and promote uniformity in the medical management of vitamin D deficiency. This CKS topic is largely based on Royal Osteoporosis Society Clinical Guideline17, the Scientific Advisory Committee on Nutrition (SACN) report25 and the NICE Public Health Guidance 5626

(please refer to source documents for comprehensive guidance).

 

Assessment of vitamin D status:

The most widely used and clinically accepted biomarker for assessing vitamin D status is the total plasma 25-hydroxyvitamin D concentration (25(OH)D, calcidiol). This is due to the relatively long circulating half-life of this metabolite. However, there is no clear consensus on the threshold concentration used to define vitamin D deficiency in adults.

 

UK vitamin D reference ranges:


The Royal Osteoporosis Society (ROS) in agreement with the National Academy of Medicine (NAM), propose that the following 25(OH)D plasma thresholds in respect to bone health are adopted by UK practitioners:

 


Evidence identified by the Scientific Advisory Committee on Nutrition (SACN) suggests that the risk of poor musculoskeletal health is increased at serum 25(OH)D concentration below 25 nmol/L (25).

The Endocrine Society Guidelines advise that to maximise the effect of vitamin D on calcium, bone and muscle metabolism, plasma 25(OH)D should exceed 75nmol/L.28

Defining vitamin D status according to ‘threshold’ plasma 25(OH)D continues to be a topic of ongoing debate necessitating the importance of reference to local clinical care guidance.

UK vitamin D testing:

 

In the UK, the Royal Osteoporosis Society have proposed a rational approach to testing in line with good-practice principles17 to support optimal resource utilisation and medical management for those at risk, additional local clinical guidance may also apply.

 

When to test for vitamin D deficiency

Routine 25(OH)D measurement in the following risk groups prior to treatment is not necessary:

 

  • Pregnant and breastfeeding women especially teenagers and young women.

  • Older people >65 years

  • People with limited exposure to sun due to clothing/sunscreen coverage or indoor lifestyle

  • People with darker skin 

Plasma 25(OH)D measurement is recommended for:

  • Patients with musculoskeletal symptoms that could be attributed to vitamin D deficiency

  • Patients with bone disease that may be improved with vitamin D treatment

  • Patients with bone disease, prior to specific treatment where correcting vitamin D deficiency is appropriate. 

How should vitamin D deficiency be treated?

For patients requiring vitamin D medical repletion, the Royal Osteoporosis Society propose supplementation with oral vitamin Das the medication of choice:

  • Intramuscular administration is associated with significant inter-individual variability in absorption.

  • Plant derived vitamin D2 is not recommended as a supplement due lower tissue bioavailability30.

  • Capsulated vitamin D dosage forms provide 32% more bioavailability compared to tablet formulations, whilst also being easier to swallow29.

Recommended dosing strategies for vitamin D deficiency in adults:

 

Where rapid correction of vitamin D deficiency is required, such as in patients with symptomatic disease or about to start treatment with a potent antiresorptive agent (zoledronate or denosumab), the recommended treatment regimen is based on fixed loading doses followed by regular maintenance therapy. Where correction of vitamin D deficiency is less urgent and when co-prescribing vitamin D supplements with an oral anti-resorptive agent, maintenance therapy may be started without the use of loading doses.

 

ROS recommended vitamin D dosing strategy in adults

Loading Dose Total

300,00 IU (7,500 micrograms) vitamin D. Doses may be administered over 6-10 weeks as either separate weekly or daily doses

Maintenance Dose

Doses equivalent to 800-2,000 IU daily (occasionally up to 4,000 IU daily), given either daily or intermittently at higher doses.

1 microgram vitamin D = 40 IU vitamin D.

 

Royal Osteoporosis Society recommended vitamin D dosing strategy for adolescents:


The Royal Osteoporosis Society currently follow the British National Formulary for Children44 recommendations for the treatment of vitamin D deficiency in adolescents:

12-17 years old: 10,000 IU orally for 8-12 weeks; a single or divided oral dose totalling 300,000 IU can be considered if there is concern about compliance. It is recognised that equivalent weekly or fortnightly dosing is likely to be effective in treating vitamin D deficiency in the population group.31,44


ROS recommended vitamin D dosing strategy in adults

Loading Dose Total

10,000 IU orally for 8-12 weeks; a single or divided oral dose totalling 300,000 IU can be considered if there is concern about compliance.

Maintenance Dose

It is recognised that equivalent weekly or fortnightly dosing is likely to be effective in treating vitamin D deficiency in the population group.

1 microgram vitamin D = 40 IU vitamin D

Follow-up and monitoring:

Routine monitoring of plasma 25(OH)D is generally unnecessary, but may be appropriate in patients with symptomatic vitamin D deficiency or malabsorption and where poor compliance with medication is suspected.

Adjusted serum calcium should be checked one month after completing the loading regimen or after starting vitamin D treatment in case primary hyperparathyroidism has been unmasked.

 

 

References
17. ROS Vitamin D and Bone Health: A practical clinical guideline for patient management. December 2018 https://nos.org.uk/for-healthprofessionals/tools-resources/  
19. NICE Clinical Knowledge Summaries. Vitamin D deficiency in adults – treatment and prevention: Summary November 2016. https://cks.nice.org.uk/vitamin-d-deficiency-in-adults-treatmentand-prevention ; Vitamin D deficiency in children:Summary November 2016. https://cks.nice.org.uk/vitamin-d-deficiency-in-children  
25. Scientific Advisory Committee on Nutrition (SACN)vitamin D and health report 21 July 2016
26. NICE. Vitamin D: increasing supplement use among at-risk groups. Public health guidance 56.NICE, 2014. www.nice.org.uk/guidance/PH5
28. Couchman L and Moniz CF: Analytical considerations for the biochemical assessment of vitamin D status; Ther Adv Musculoskel Dis 2017,Vol.9(4) 97-10429.

29. Grossman RE and Tangpricha V. Mol Nutr Food Res 2010; 54(8): 1055-61
30. Heaney RP et al. J Clin Endocrinol Metab 2011;96(3): E447-52

31. ROS Vitamin D and Bone Health. A practical clinical guideline for management in children and young people November 2018 https://nos.org.uk/for-health-professionals/tools-resources/
44.British National Formulary for Children 2017-2018London:BMJ Group 2018.Section 9.7 Vitamin Deficiency

Job code: FUL-519  
Date of preparation: June 2019