Vitamin D Deficiency

Diagnosis and Management
Vitamin D Test Therapy(i)

Deficiency: < 10 ng/mL (< 25 nmol/L)(ii)

 

Insufficiency: < 20 ng/mL (< 50 nmol/L)

 Serum 25-hydroxy vitamin D (25[OH]D). If deficient, consider checking parathyroid hormone (PTH), calcium, phosphate(iii), alkaline phosphatase

If vitamin D deficient, replacement recommended. Various regimens suggested(iv)
Supplementation with vitamin D may reduce bone loss with initiation of ART, see Bone Disease: Screening and Diagnosis
Consider re-checking 25(OH) vitamin D levels 3 months after replacement. After replacement, maintenance with 800-2000 IU vitamin D daily

Vitamin D insufficiency is prev­alent (>80%) in some cohorts of populations with and without HIV – may not be directly associated with HIV

Factors associated with lower vitamin D:
  • Dark skin
  • Dietary deficiency
  • Avoidance of sun exposure
  • Malabsorption
  • Obesity
  • CKD
  • Some ARVs(v)

Check vitamin D status in persons with history of:

  • low bone mineral density and/or fracture
  • high risk for fracture

Consider assessment of vitamin D status in persons with other factors associated with lower vitamin D levels (see left column)

Replacement and/or supplementation of vitamin D is recommended for persons with both vitamin D insufficiency(vi) and one of the following:

  • osteoporosis
  • osteomalacia
  • increased PTH (once the cause has been identified)

Consider re-testing after 6 months of vitamin D intake

 

  1. Can be provided according to national recommendations/availability of preparations (oral and parenteral formulations). Combine with calcium where there is insufficient dietary calcium intake. Consider that in some countries food is artificially fortified with vitamin D
  2. Vitamin D insufficiency has a prevalence of up to 80% in HIV cohorts and was associated with increased risk for osteoporosis, type 2 diabetes, mortality and AIDS events. However, causal association not proven for all outcomes. Consider seasonal differences (in winter approximately 20% lower than in summer)
  3. Consider that hypophosphataemia can be associated with TDF therapy. This phosphate loss through proximal renal tubulopathy may be independent of low vitamin D, see Indication and Tests for Proximal Renal Tubulopathy. A combination of low calcium + low phosphate +/- high alkaline phosphatase may indicate osteomalacia and vitamin D deficiency
  4. Expect that 100 IU vitamin D daily leads to an increase in serum 25(OH) vitamin D of approximately 1 ng/mL. Some experts prefer a loading dose of e.g. 10,000 IU vitamin D daily for 8-10 weeks in persons with vitamin D deficiency. The principal goal is to achieve a serum level > 20 ng/ mL (50 nmol/L) and to maintain normal serum PTH levels. Combine with calcium where potential for insufficient dietary calcium intake. The therapeutic aim is to maintain skeletal health; vitamin D supplementation has not been proven to prevent other co-morbidities in persons with HIV
  5. The role of HIV-therapy or specific drugs remains unclear. Some studies suggest an association of EFV with reductions in 25(OH)D but not 1,25(OH)D. PIs may also affect vitamin D status by inhibiting conversion of 25(OH)D to 1,25(OH)D
  6. The implications of vitamin D levels that are below the physiological reference range but not markedly reduced and the value of supplementation in that situation are not completely understood