title: Derivation and External Validation of a Prediction Rule for Five-Year Mortality in Patients With Early Diffuse Cutaneous Systemic Sclerosis.
abstract: OBJECTIVE
  Although diffuse cutaneous systemic sclerosis (dcSSc) is associated with a reduction in life expectancy, there are no validated prognostic models for determining 5-year mortality in patients with dcSSc. The objective of this study was to derive and validate a rule for predicting 5-year mortality in patients with early dcSSc.
  
  
  METHODS
  We studied an inception cohort of 388 US Caucasian patients with early dcSSc (<2 years from the appearance of the first symptom). Predefined baseline variables were analyzed in a stepwise logistic regression model in order to identify factors independently associated with 5-year all-cause mortality. We rounded the beta weights to the nearest integer and summed the points assigned to each variable in order to stratify patients into low-risk (<0 points), moderate-risk (1-2 points), and high-risk (≥3 points) groups. We then applied this rule to an external validation cohort of 144 Caucasian patients with early dcSSc from the Royal Free Hospital cohort and compared stratum-specific 5-year mortality.
  
  
  RESULTS
  Six independent predictors (rounded beta weight) comprised the model: age at first visit (points allotted: -1, 0, or 1), male sex (points allotted: 0 or 1), tendon friction rubs (points allotted: 0 or 1), gastrointestinal involvement (points allotted: 0 or 1), RNA polymerase III antibodies (points allotted: 0 or 1), and anemia (points allotted: 0 or 1). The 3-level risk stratification model performed well, with no significant differences between the US derivation cohort and the UK validation cohort.
  
  
  CONCLUSIONS
  We derived and externally validated, in US and UK cohorts, an easy-to-use 6-variable prediction rule that assigns low-risk, moderate-risk, and high-risk categories for 5-year mortality in patients with early dcSSc. Only history, physical examination, and basic laboratory assessments are required.
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Robyn T
authors.initials: RT
authors.lastname: Domsic
authors.affiliation: University College London Medical School, Royal Free Hospital, London, UK.
authors.forename: Svetlana I
authors.initials: SI
authors.lastname: Nihtyanova
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Wisniewski
authors.affiliation: University of Pittsburgh and Veterans Affairs Center for Health Equity Research and Promotion, Veterans Affairs Pittsburgh Healthcare, Pittsburgh, Pennsylvania.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Fine
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Mary
authors.initials: M
authors.lastname: Lucas
authors.affiliation: University of Arizona Arthritis Center, Tucson.
authors.forename: C Kent
authors.initials: CK
authors.lastname: Kwoh
authors.affiliation: University College London Medical School, Royal Free Hospital, London, UK.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Denton
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Medsger
mesh_terms: D000328:Adult; D000740:Anemia / Q000453:epidemiology*; D001323:Autoantibodies / Q000276:immunology; D015331:Cohort Studies; D003661:Decision Support Techniques; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012320:RNA Polymerase III / Q000276:immunology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D045743:Scleroderma, Diffuse / Q000276:immunology / Q000401:mortality*; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
chemical_list: D001323:Autoantibodies; D012320:RNA Polymerase III