Increased incidence of multiple sclerosis in systemic sclerosis: A nationwide cohort study.

Objective: Previous studies showed inconsistent results on the association of systemic sclerosis (SSc) with multiple sclerosis (MS), and are limited by a lack of adjustment for sex and age. The goals of this retrospective cohort study were to evaluate whether SSc is associated with increased incident MS independent of sex and age.
Methods: We enrolled patients with SSc from Taiwan's Registry of Catastrophic Illness Database and referent subjects from the National Health Insurance Research Database. Each SSc patient was matched to at most three referent subjects by sex, age, month and year of initial diagnosis of SSc. Incidence of MS in SSc patients and corresponding 95% confidence interval (95% CI) were calculated. Cox hazard regression was used to calculate the hazard ratio (HR) of MS.
Results: The study enrolled 1171 patients with SSc and 3409 referent subjects. Patients with SSc had higher incidence of MS than referent subjects (9.35 per 1000 person-years, 95% CI=6.86-11.85; 0.13 per 1000 person-years, 95% CI=0.03-0.37, respectively). Similar results also occurred in both men and women. SSc was associated with increased incidence of MS after adjusting for sex and age (HR: 69.48, 95% CI=21.69-222.54).
Conclusion: SSc is associated with increased incidence of MS, independent of sex and age of the patients. Multidisciplinary teams should guide the assessment, treatment, and holistic care of SSc patients to reduce its morbidity.
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