title: Reading radiographs in chronological order, in pairs or as single films has important implications for the discriminative power of rheumatoid arthritis clinical trials.
abstract: OBJECTIVE
  To determine the influence of reading series of films in chronological order, in pairs with unknown time sequence, or as single films, on precision and sensitivity to change.
  
  
  METHODS
  Two studies were performed with 10 and 12 patients fulfilling the American College of Rheumatology criteria. In Study 1, two sets of films with a 1 yr interval were scored in chronological order, in pairs, and as single films. In Study 2, four sets of films, with a 1 yr interval each, were scored in chronological order, as single films and as single-pair (right and left together). All films were scored with the Sharp/van der Heijde method by two independent observers. Data were analysed with a repeated measures ANOVA using a full mixed effects model. Two generalizability (G) coefficients were constructed for reliability and for change.
  
  
  RESULTS
  Study 1: the interobserver reliability was similar for the three methods (G(reliability) chronological 0.94, paired 0.88, single 0.93); progression was a mean increase (averaged over patients, observers and methods) from 26 to 37 (P=0.046). The sensitivity for change was greater for the chronological than for the paired and single scoring (G(change) 0.39, 0.22 and 0.24, respectively). Study 2: the interobserver reliability was 0.86 for chronological, 0.76 for single-pair and 0.91 for single readings. Significantly more progression was measured with the chronological compared with the single-paired and single methods (15.9 vs 8.5 and 8.3; P=0.0001). A constant progression was suggested by chronological reading, in contrast to a stabilization in the other two methods after 1 yr.
  
  
  CONCLUSIONS
  Reading films in chronological order is most sensitive to change in a time period up to 3 yr follow-up; this was already present after 1 yr, but even more pronounced with longer follow-up.
authors.affiliation: Department of Internal Medicine, Division of Rheumatology, University Hospital Maastricht, Maastricht, The Netherlands.
authors.forename: D
authors.initials: D
authors.lastname: van Der Heijde
authors.forename: A
authors.initials: A
authors.lastname: Boonen
authors.forename: M
authors.initials: M
authors.lastname: Boers
authors.forename: P
authors.initials: P
authors.lastname: Kostense
authors.forename: S
authors.initials: S
authors.lastname: van Der Linden
mesh_terms: D000704:Analysis of Variance; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging*; D002910:Chronology as Topic; D005500:Follow-Up Studies; D006801:Humans; D015233:Models, Statistical; D015588:Observer Variation; D017063:Outcome Assessment, Health Care; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012680:Sensitivity and Specificity