Uveitis increases risk of multiple sclerosis relapse

This study assessed the long-term incidence and prevalence of uveitis and its association with multiple sclerosis.

Study design

Researchers analyzed pooled data from 27,528 patients with multiple sclerosis who were enrolled in fingolimod clinical trials and extension studies. The study included patients with relapsing and primary progressive disease. The average time since multiple sclerosis diagnosis was 7.4 years. Main outcomes included the incidence and prevalence of uveitis, and MS outcome measures such as annualized relapse rate (ARR), time to first relapse, change in Expanded Disability Status Scale (EDSS) score from baseline, and proportion of patients with 6-month confirmed disability progression.

Outcomes

One hundred and eighty-nine patients had uveitis before enrollment or during the study period. Of these, 162 patients had a history of uveitis at baseline and 27 developed the disease during the study. The overall incidence (0.1 per 100 patients-years) and prevalence (0.59%) of uveitis were lower than in previous studies.

Patients with uveitis at baseline were significantly older (P=0.003) and had more T2 lesions (P=0.018) but experienced fewer relapses in the previous 2 years (1.7 vs. 2.0; P=0.022) than patients without uveitis at study entry. Additionally, patients with uveitis had a shorter time-to-first relapse (2.1 vs. 8.1; P=0.047) and a 50% higher ARR (0.31 vs. 0.21; P=0.025). Changes in EDSS and the proportion individuals with confirmed disability progression, however, were no different between groups.

Limitations

Researchers used self-reported history of uveitis and may have therefore introduced potential biases or inaccuracies. There may have also been selection biases because patients with macular edema were excluded from randomized fingolimod trials.

Clinical significance

Given the high overall incidence and prevalence of uveitis in this study, patients with multiple sclerosis should be carefully screened. Uveitis should be considered as a risk factor for greater multiple sclerosis disease activity. In patients with multiple sclerosis, modulated inflammatory response by the HLA system and the possible presence of autoantibodies against brain and retinal arrestin may play a role in the pathophysiology of MS-associated uveitis.