rss
Ann Rheum Dis 2004;63:1601-1604 doi:10.1136/ard.2004.022038
  • Extended report

Scoring of radiographic progression in randomised clinical trials in ankylosing spondylitis: a preference for paired reading order

  1. A Wanders1,
  2. R Landewé1,
  3. A Spoorenberg1,
  4. K de Vlam2,
  5. H Mielants2,
  6. M Dougados3,
  7. S van der Linden1,
  8. D van der Heijde1
  1. 1Department of Internal Medicine, Division of Rheumatology, University Hospital Maastricht, The Netherlands
  2. 2Department of Rheumatology, University Hospital Gent, Belgium
  3. 3Department of Rheumatology, Hôpital Cochin Paris, France
  1. Correspondence to:
    Dr R Landewé
    Department of Internal Medicine, Division of Rheumatology, University Hospital Maastricht, PO Box 5800, 6202 AZ Maastricht, The Netherlands; rlansint.azm.nl
  • Accepted 20 June 2004
  • Published Online First 5 August 2004

Abstract

Objectives: To describe the influence of the reading order (chronological v paired) on radiographic scoring results in ankylosing spondylitis. To investigate whether this method is sufficiently sensitive to change because paired reading is requested for establishing drug efficacy in clinical trials.

Methods: Films obtained from 166 patients (at baseline, 1 year, and 2 years) were scored by one observer, using the modified Stoke Ankylosing Spondylitis Spinal Score. Films were first scored chronologically, and were scored paired 6 months later.

Results: Chronological reading showed significantly more progression than paired reading both at 1 year (mean (SD) progression 1.3 (2.6) v 0.5 (2.4) units) and at 2 years (2.1 (3.9) v 1.0 (2.9) units); between-method difference: p<0.001 at 1 year, and p<0.001 at 2 years. After 1 year, progression (>0 units) was found in 35/166 (21%) patients after paired reading and in 55/166 (33%) after chronological reading. After 2 years, these figures were 50/166 (30%) and 68/166 (41%), respectively. Sample size calculations showed that 94 patients in each treatment arm are required in a randomised clinical trial (RCT) to provide sufficient statistical power to detect a difference in 2 year progression if films are scored paired.

Conclusion: Reading with chronological time order is more sensitive to change than reading with paired time order, but paired reading is sufficiently sensitive to pick up change with a follow up of 2 years, resulting in an acceptable sample size for RCTs.

Footnotes

    This Article

    1. Abstract
    2. Full text
    3. PDF
    4. All versions of this article:
      1. ard.2004.022038v1
      2. 63/12/1601 most recent

    Responses

    1. Submit a response
    2. No responses published

    Register for free content

    The full back archive is now available for all BMJ Journals. Institutional subscribers may access the entire archive as part of their subscription. Personal subscribers will also have access to all content when logged in. Non-subscribers who register have free access to all articles published before 2006 right back to volume 1 issue 1. Register here to access the free archive of all BMJ Journals.

    Don't forget to sign up for content alerts so you keep up to date with all the articles as they are published.