Inflammatory activity and vitamin D levels in an MS population treated with rituximab

Abstract

Background: Most multiple sclerosis patients on disease-modifying treatment at Umeå University Hospital are treated with rituximab and the prevalence of vitamin D supplementation has increased over time. Follow-up studies of these off-label treatments are needed.

Objective: To study inflammatory activity and adverse effects in rituximab-treated multiple sclerosis patients, and associations with 25-hydroxy-vitamin D levels.

Methods: Retrospectively collected data on repeated estimates of relapses, disability, side effects, magnetic resonance imaging, laboratory measures including 25-hydroxy-vitamin D levels and self-perceived health.

Results: In 272 multiple sclerosis patients with a mean follow-up of 43 months, we identified seven possible relapses during active rituximab treatment. On magnetic resonance imaging examination, new T2 lesions were seen in 1.3% (10 out of 792 scans), and 0.25% (two out of 785 scans) showed contrast enhancement. Adjusted 25-hydroxy-vitamin D levels in samples drawn close to all magnetic resonance images with new T2 lesions were lower compared to the remainder (62 vs. 81 nmol/l; P = 0.030). Levels of 25-hydroxy-vitamin D were associated with self-perceived health (r = 0.18, P = 0.041, n = 130) and C-reactive protein (r = -0.13, P = 0.042) but not with the risk of side effects.

Conclusion: The inflammatory activity in this rituximab-treated multiple sclerosis population that increasingly used vitamin D supplementation was extremely low. Higher 25-hydroxy-vitamin D levels were associated with beneficial outcomes.

Keywords: MRI; Multiple sclerosis; disease-modifying therapies; rituximab; vitamin D.

Figure 1.

Vitamin D supplementation among rituximab-treated multiple sclerosis (MS) patients by year. The number of patients active in the study (grey bar) each year and how many of them were receiving vitamin D supplementation (white bar) are shown. Vitamin D median dose (black line) was calculated using all MS patients from this study, even if they had not yet started rituximab treatment. IU: international units.

Figure 2.

Median 25-hydroxy vitamin D (25(OH)D) levels among multiple sclerosis (MS) patients over time. The median serum 25(OH)D level and the number of analyses each year. The black lines represent the 25 to 75 percentiles of the samples.