MEASUREMENT AND PREDICTION OF RADIOLOGICAL PROGRESSION IN EARLY RHEUMATOID-ARTHRITIS

Objective. To compare radiological scoring systems in early RA, and th en to determine if the rate of radiological progression in the first y ear of disease (RRP01) predicts the subsequent rate of progression up to 8 years (RRP1-8). Methods. Hand and feet radiographs were performed at 0, 1, 2 and 8 years in 65 patients presenting with nonerosive RA a nd symptoms for less than 3 years. All films were scored by Sharp's me thod; Sharp, Larsen and carpometacarpal (CMC) ratio methods were compa red in 23 patients. Results. Significant change in score was detected over the first year using Sharp (median of 15.5 vs 7.5, p <0.00002) an d Larsen (30.5 vs 22.5, p <0.0002), but not CMC ratio (1.13 vs 1.14, p = 0.07). Sharp had greater range and sensitivity of change, and had b etter inter and intraobserver reproducibility. RRP01 showed a skewed d istribution (median 0.7 units/month; range -0.3 to +6.1). Spearman cor relation between RRP01 and RRP1-8 was r = 0.57, p < 0.001. Conclusion. Both Sharp and Larsen indices are sensitive to change in the first ye ar of RA, but Sharp has advantages of greater sensitivity and reproduc ibility: CMC ratio is not useful. Radiological progression rate in the first year correlates only moderately with subsequent rate of progres sion up to 8 years. This suggests that radiological progression is non uniform and that different patterns of progression over time may exist .