title: Sub-typing of rheumatic diseases based on a systems diagnosis questionnaire.
abstract: BACKGROUND
  The future of personalized medicine depends on advanced diagnostic tools to characterize responders and non-responders to treatment. Systems diagnosis is a new approach which aims to capture a large amount of symptom information from patients to characterize relevant sub-groups.
  
  
  METHODS
  49 patients with a rheumatic disease were characterized using a systems diagnosis questionnaire containing 106 questions based on Chinese and Western medicine symptoms. Categorical principal component analysis (CATPCA) was used to discover differences in symptom patterns between the patients. Two Chinese medicine experts where subsequently asked to rank the Cold and Heat status of all the patients based on the questionnaires. These rankings were used to study the Cold and Heat symptoms used by these practitioners.
  
  
  RESULTS
  The CATPCA analysis results in three dimensions. The first dimension is a general factor (40.2% explained variance). In the second dimension (12.5% explained variance) 'anxious', 'worrying', 'uneasy feeling' and 'distressed' were interpreted as the Internal disease stage, and 'aggravate in wind', 'fear of wind' and 'aversion to cold' as the External disease stage. In the third dimension (10.4% explained variance) 'panting s', 'superficial breathing', 'shortness of breath s', 'shortness of breath f' and 'aversion to cold' were interpreted as Cold and 'restless', 'nervous', 'warm feeling', 'dry mouth s' and 'thirst' as Heat related. 'Aversion to cold', 'fear of wind' and 'pain aggravates with cold' are most related to the experts Cold rankings and 'aversion to heat', 'fullness of chest' and 'dry mouth' to the Heat rankings.
  
  
  CONCLUSIONS
  This study shows that the presented systems diagnosis questionnaire is able to identify groups of symptoms that are relevant for sub-typing patients with a rheumatic disease.
authors.affiliation: Division of Analytical Biosciences, LACDR, Leiden University, Leiden, The Netherlands. h.vanwietmarschen@lacdr.leidenuniv.nl
authors.forename: Herman A
authors.initials: HA
authors.lastname: van Wietmarschen
authors.forename: Theo H
authors.initials: TH
authors.lastname: Reijmers
authors.forename: Anita J
authors.initials: AJ
authors.lastname: van der Kooij
authors.forename: Jan
authors.initials: J
authors.lastname: Schroën
authors.forename: Heng
authors.initials: H
authors.lastname: Wei
authors.forename: Thomas
authors.initials: T
authors.lastname: Hankemeier
authors.forename: Jacqueline J
authors.initials: JJ
authors.lastname: Meulman
authors.forename: Jan
authors.initials: J
authors.lastname: van der Greef
mesh_terms: D003080:Cold Temperature; D006358:Hot Temperature; D006801:Humans; D008954:Models, Biological; D012216:Rheumatic Diseases / Q000145:classification* / Q000175:diagnosis*; D011795:Surveys and Questionnaires