Comparison of three radiologic scoring systems for the long-term assessment of rheumatoid arthritis - Findings of an ongoing prospective inception cohort study of 132 women followed up for a median of twelve years

Objective. To compare the sensitivity and efficiency of 3 different radiolo gic scoring systems in measuring radiologic progression of rheumatoid arthr itis (RA) over a 12-year period. Methods. Radiographs of the hands and feet of 112 RA patients were assessed at 0, 3, 6, and 12 years of disease duration using the Sharp score as modi fied by van der Heijde (SRS), the Sharp score with increased maximum scores (Sharp Max), and the Kellgren score. The sensitivity to change was tested using the standardized response mean (SRM); the efficiency was determined b y calculating the number of patients needed to detect 50% difference in pro gression between 2 patient groups. Results. Radiologic abnormalities were steadily progressive irrespective of the scoring method used. In early disease, the SRM was significantly large r for the SHS and Kellgren scores compared with the Sharp Max score. In lat e disease, the Kellgren score was slightly more sensitive to change compare d with the SHS and Sharp Max scores; the difference, however, did not reach significance. In erosive disease, the SRM was significantly larger for the Kellgren compared with the SHS and Sharp Max scores. The numbers of patien ts needed to detect a 50% difference during the 0-3-year followup period we re 129, 138, and 124 for the SHS, the Sharp Max, and the Kellgren, respecti vely. The numbers of patients needed to detect a 50% difference during the 6-12-year followup period were 117, 121, and 104, respectively. The numbers of patients needed to detect a 50% difference during the 6-12-year followu p in patients with erosive disease were 74, 78, and 68, respectively, for t he 3 scores. The gellgren required 33 minutes to score 10 sets of radiograp hs of the hands and feet; the SHS score took 55 minutes. Conclusion. The Kellgren scoring system is the most efficient method for mo nitoring the radiologic progression of RA. The Kellgren and the SHS are equ ally sensitive to change early in the disease, whereas the Kellgren score b ecomes more sensitive to change late in the disease in patients with erosio ns.