What are the indications for vitamin D supplementation in patients on long-term steroid therapy, specifically glucocorticoids (GCs)?

From the Guidelines

Vitamin D supplementation is recommended for all patients on long-term glucocorticoid therapy, specifically those expected to receive prednisone >7.5 mg daily (or equivalent) for more than 3 months, to prevent bone loss and reduce fracture risk. Patients should receive 800-1000 IU of vitamin D daily, with some requiring higher doses of 1000-2000 IU daily if they have documented vitamin D deficiency (25-hydroxyvitamin D levels <30 ng/mL) 1. Calcium supplementation of 1000-1200 mg daily should also be provided alongside vitamin D. This recommendation is based on the highest quality evidence from the 2017 American College of Rheumatology guideline for the prevention and treatment of glucocorticoid-induced osteoporosis 1.

Key Considerations

• Glucocorticoids impair bone health through multiple mechanisms, including decreased calcium absorption, increased urinary calcium excretion, reduced osteoblast function, and increased osteoclast activity.
• Vitamin D supplementation helps counteract these effects by enhancing intestinal calcium absorption, supporting bone mineralization, and potentially reducing the risk of steroid-induced osteoporosis.
• Patients should have baseline and follow-up bone mineral density testing, and those at high fracture risk may need additional bone-protective medications such as bisphosphonates.
• Vitamin D levels should be monitored periodically, especially in patients with malabsorption or other risk factors for deficiency.

Risk Assessment and Management

• Assess patients for osteoporosis risk factors, including previous fragility fracture, prolonged or repeated courses of steroids, age, and bone mineral densitometry results.
• Consider prolonged bisphosphonate treatment, and/or referral to specialist clinic as appropriate.
• Start bisphosphonate therapy as per UK guidelines, and ensure calcium and vitamin D intake.
• Arrange bone mineral densitometry as soon as possible, and repeat at 1-3 year intervals depending on risk.

Recent Guidelines

• The 2019 British Society of Gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults recommend vitamin D supplementation and calcium intake for patients on long-term corticosteroids 1.
• The guidelines also provide a framework for assessing and managing osteoporosis risk in patients with inflammatory bowel disease.

Overall, vitamin D supplementation is a crucial component of osteoporosis prevention and management in patients on long-term glucocorticoid therapy, and should be tailored to individual patient needs and risk factors 1.

From the Research

Indications for Vitamin D Supplementation

The indications for vitamin D supplementation in patients on long-term steroid therapy, specifically glucocorticoids (GCs), are primarily focused on preventing and treating glucocorticoid-induced osteoporosis (GIOP). Key points include:

• Vitamin D/calcium substitution is regarded as an effective first-step treatment for GIOP 2.
• Vitamin D plus calcium is superior to no therapy or calcium alone in managing corticosteroid-induced osteoporosis 3.
• The use of supplemental calcium is recommended for patients receiving prednisone, with vitamin D potentially offering additional benefits 4.

Mechanisms and Considerations

The mechanisms behind glucocorticoid-induced osteoporosis involve:

• Direct impairment of osteoblast, osteocyte, and osteoclast function leading to reduced bone remodeling 5.
• Antagonism of gonadal function and inhibition of the osteoanabolic action of sex steroids 5.
• Increased renal elimination and reduced intestinal absorption of calcium, potentially promoting secondary hyperparathyroidism 5.
• Vitamin D plays a role in mitigating some of these effects, though its role is considered lesser compared to other factors like parathyroid hormone (PTH) 5.

Clinical Evidence and Recommendations

Clinical studies suggest that:

• Vitamin D supplementation, particularly when combined with calcium, can help prevent bone loss and reduce the risk of fractures in patients on long-term glucocorticoid therapy 2, 3, 6.
• The absence of calcium/vitamin D supplementation is a significant factor explaining the presence of fractures in these patients 6.
• Bone mineral density is a major determinant of fracture risk, but glucocorticoid dose and the absence of calcium/vitamin D supplementation also play critical roles 6.