title: Epidemiology of Mixed Connective Tissue Disease, 1985-2014: A Population-Based Study.
abstract: To characterize the epidemiology of mixed connective tissue disease (MCTD) from 1983 to 2014.
  
  
  
  An inception cohort of patients with incident MCTD in 1985-2014 in Olmsted County, Minnesota was identified based on comprehensive individual medical record review. Diagnosis of MCTD required fulfillment of at least 1 of the 4 widely accepted diagnostic criteria without fulfillment of classification criteria for other connective tissue diseases. Data were collected on demographic characteristics, clinical presentation, laboratory investigations, and mortality.
  
  
  
  A total of 50 incident cases of MCTD were identified (mean age 48.1 years and 84% were female). The annual incidence of MCTD was 1.9 per 100,000 population. Raynaud's phenomenon was the most common initial symptoms (50%), followed by arthralgia (30%) and swollen hands (16%). The diagnosis was frequently delayed with the median time from first symptom to fulfillment of criteria of 3.6 years. At fulfillment of criteria, arthralgia was the most prevalent manifestation (86%), followed by Raynaud's phenomenon (80%), swollen hands (64%), leukopenia/lymphopenia (44%), and heartburn (38%). Evolution to other connective tissue occurred infrequently with a 10-year rate of evolution of 8.5% and 6.3% for systemic lupus erythematosus and systemic sclerosis, respectively. The overall mortality was not different from the general population with a standardized mortality ratio of 1.1 (95% confidence interval 0.4-2.6).
  
  
  
  This study was the first population-based study of MCTD to provide a complete picture of epidemiology and clinical characteristics of MCTD. MCTD occurred in about 2 persons per 100,000 per year. Evolution to other connective diseases occurred infrequently and the mortality was not affected.
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Patompong
authors.initials: P
authors.lastname: Ungprasert
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Crowson
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Vaidehi R
authors.initials: VR
authors.lastname: Chowdhary
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Floranne C
authors.initials: FC
authors.lastname: Ernste
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Moder
authors.affiliation: Mayo Clinic, Rochester, Minnesota.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Matteson
mesh_terms: D000328:Adult; D018771:Arthralgia / Q000453:epidemiology / Q000209:etiology; D015331:Cohort Studies; D004487:Edema / Q000453:epidemiology / Q000209:etiology; D005260:Female; D006225:Hand; D006356:Heartburn / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D015994:Incidence; D007970:Leukopenia / Q000453:epidemiology / Q000209:etiology; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D008947:Mixed Connective Tissue Disease / Q000150:complications / Q000453:epidemiology*; D011928:Raynaud Disease / Q000453:epidemiology / Q000209:etiology; D013997:Time Factors