Dosing Strategy of Vitamin D therapy in Patients with Rheumatic Diseases in Bahrain

Abstract

Purpose: The assessment of vitamin D status (25(OH)D) and dosing strategies for patients with rheumatic diseases (RDs) in Bahrain are lacking. The current study aimed to determine serum 25(OH)D levels at baseline and after Cholecalciferol (Vitamin D3) therapy and to assess the changes in serum levels in response to three different regimens in adult patients with RDs in Bahrain. Methods: Data was collected retrospectively from 158 patients with RDs, during a period 20132019- at King Abdullah Medical City. The mean age of the patients was 45 years (range 18 - 83 years). Two third (66.46%, 105) of them were females. The controls were adult sex- and age-matched healthy volunteers. All patients were investigated for vitamin D status during their first visits. Three regimens of Vitamin D3 therapy were assessed: Regimen1. A single parenteral dose of 600.000 IU. Regimen2. An oral dose of 50.000 IU weekly for 12 weeks, Regimen3. Maintenance oral dose whenever a patient achieved an optimal level. Results: The patients had lower serum levels of vitamin D3 compared to controls (P-Value=0.001; 95%C.I. (3.870, 15.599)). There was a statistically significant increase in mean serum levels of Vitamin D3 in Parenteral compared to Oral therapy (P-value<0.0005). In the patient group, vitamin D3 therapy leads to a statistically significant increase in its baseline level (P-value<0.0005), but the reduction in vitamin D3 from the therapeutic levels during maintenance was statistically not significant (P-value=0.177). Conclusion: The significant increase in serum 25(OH)D levels from baseline in response to Vitamin D3 regimens was best achieved with single parenteral therapy of 600.000 IU. Maintenance therapy to maintain optimal level year-round is a must, and the best dose was 50.000 IU orally every 24- weeks.