title: Increased incidence of multiple sclerosis in systemic sclerosis: A nationwide cohort study.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Internal Medicine, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Tseng
authors.affiliation: Department of Kinesiology, Health and Leisure Studies, National University of Kaohsiung, Kaohsiung, Taiwan.
authors.forename: Shun-Jen
authors.initials: SJ
authors.lastname: Chang
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Wen-Chan
authors.initials: WC
authors.lastname: Tsai
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Tsan-Teng
authors.initials: TT
authors.lastname: Ou
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Cheng-Chin
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Sung
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan; Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Ming-Chia
authors.initials: MC
authors.lastname: Hsieh
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan. Electronic address: jehsye@cc.kmu.edu.tw.
authors.forename: Jeng-Hsien
authors.initials: JH
authors.lastname: Yen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology / Q000209:etiology*; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012595:Scleroderma, Systemic / Q000150:complications*; D013624:Taiwan / Q000453:epidemiology
keywords: Cohort studies; Multiple sclerosis; Retrospective studies; Systemic sclerosis