title: Novel Composite Radiographic Score for Longitudinal Observational Studies of Psoriatic Arthritis: A Proof-of-concept Study.
abstract: OBJECTIVE
  To devise a feasible composite radiographic score for use in observational studies of psoriatic arthritis (PsA).
  
  
  METHODS
  Radiographs from 50 patients with PsA were evaluated with the PsA-modified Sharp, Sharp/van der Heijde (SvdH), and Ratingen scores. Data reductions were made to devise a concise score.
  
  
  RESULTS
  The Reductive X-ray Score for Psoriatic Arthritis (ReXSPA) required the assessment of only 22 joints (117 points), including erosion, joint space narrowing, and osteoproliferation in the hands and feet. The ReXSPA accounted for 80% of change detected with the SvdH score.
  
  
  CONCLUSIONS
  We report a proof-of-concept radiographic score for observational studies derived though data reduction.
authors.affiliation: From the Royal National Hospital for Rheumatic Diseases; Department of Mathematics, University of Bath; Department of Pharmacy and Pharmacology, University of Bath; Department of Radiology, Royal United Hospital, Bath, UK.W. Tillett, BSc, MBChB, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; G. Shaddick, MSc, PhD, Department of Mathematics, University of Bath; D. Jadon, MBBCh, MRCP, Royal National Hospital for Rheumatic Diseases; G. Robinson, MBBS, FRCR, Department of Radiology, Royal United Hospital; E. Korendowych, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; N. McHugh, MB, ChB, MD, FRCP, Department of Pharmacy and Pharmacology, University of Bath. w.tillett@nhs.net.
authors.forename: William
authors.initials: W
authors.lastname: Tillett
authors.affiliation: From the Royal National Hospital for Rheumatic Diseases; Department of Mathematics, University of Bath; Department of Pharmacy and Pharmacology, University of Bath; Department of Radiology, Royal United Hospital, Bath, UK.W. Tillett, BSc, MBChB, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; G. Shaddick, MSc, PhD, Department of Mathematics, University of Bath; D. Jadon, MBBCh, MRCP, Royal National Hospital for Rheumatic Diseases; G. Robinson, MBBS, FRCR, Department of Radiology, Royal United Hospital; E. Korendowych, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; N. McHugh, MB, ChB, MD, FRCP, Department of Pharmacy and Pharmacology, University of Bath.
authors.forename: Gavin
authors.initials: G
authors.lastname: Shaddick
authors.affiliation: From the Royal National Hospital for Rheumatic Diseases; Department of Mathematics, University of Bath; Department of Pharmacy and Pharmacology, University of Bath; Department of Radiology, Royal United Hospital, Bath, UK.W. Tillett, BSc, MBChB, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; G. Shaddick, MSc, PhD, Department of Mathematics, University of Bath; D. Jadon, MBBCh, MRCP, Royal National Hospital for Rheumatic Diseases; G. Robinson, MBBS, FRCR, Department of Radiology, Royal United Hospital; E. Korendowych, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; N. McHugh, MB, ChB, MD, FRCP, Department of Pharmacy and Pharmacology, University of Bath.
authors.forename: Deepak
authors.initials: D
authors.lastname: Jadon
authors.affiliation: From the Royal National Hospital for Rheumatic Diseases; Department of Mathematics, University of Bath; Department of Pharmacy and Pharmacology, University of Bath; Department of Radiology, Royal United Hospital, Bath, UK.W. Tillett, BSc, MBChB, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; G. Shaddick, MSc, PhD, Department of Mathematics, University of Bath; D. Jadon, MBBCh, MRCP, Royal National Hospital for Rheumatic Diseases; G. Robinson, MBBS, FRCR, Department of Radiology, Royal United Hospital; E. Korendowych, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; N. McHugh, MB, ChB, MD, FRCP, Department of Pharmacy and Pharmacology, University of Bath.
authors.forename: Graham
authors.initials: G
authors.lastname: Robinson
authors.affiliation: From the Royal National Hospital for Rheumatic Diseases; Department of Mathematics, University of Bath; Department of Pharmacy and Pharmacology, University of Bath; Department of Radiology, Royal United Hospital, Bath, UK.W. Tillett, BSc, MBChB, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; G. Shaddick, MSc, PhD, Department of Mathematics, University of Bath; D. Jadon, MBBCh, MRCP, Royal National Hospital for Rheumatic Diseases; G. Robinson, MBBS, FRCR, Department of Radiology, Royal United Hospital; E. Korendowych, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; N. McHugh, MB, ChB, MD, FRCP, Department of Pharmacy and Pharmacology, University of Bath.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Korendowych
authors.affiliation: From the Royal National Hospital for Rheumatic Diseases; Department of Mathematics, University of Bath; Department of Pharmacy and Pharmacology, University of Bath; Department of Radiology, Royal United Hospital, Bath, UK.W. Tillett, BSc, MBChB, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; G. Shaddick, MSc, PhD, Department of Mathematics, University of Bath; D. Jadon, MBBCh, MRCP, Royal National Hospital for Rheumatic Diseases; G. Robinson, MBBS, FRCR, Department of Radiology, Royal United Hospital; E. Korendowych, PhD, MRCP, Royal National Hospital for Rheumatic Diseases; N. McHugh, MB, ChB, MD, FRCP, Department of Pharmacy and Pharmacology, University of Bath.
authors.forename: Neil
authors.initials: N
authors.lastname: McHugh
mesh_terms: D015535:Arthritis, Psoriatic / Q000000981:diagnostic imaging*; D018450:Disease Progression; D005260:Female; D050823:Hand Joints / Q000000981:diagnostic imaging*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index
keywords: OUTCOME ASSESSMENT; PSORIATIC ARTHRITIS; RADIOGRAPHY