Rate of changes in the binary sacroiliac joint outcome measure
| Outcome | X-ray intervals of 2 years ± 6 months 894 intervals in 515 patients | |
| Intervals with potential progression N=703 | Intervals with potential regression N=867 | |
| Main analysis: 2 readers* | ||
| Progression | 24 (3.4%) | |
| Regression | 1 (0.12%) | |
| Sensitivity analysis: integrating a third scoring† | ||
| Progression | 105 (14.9%) | |
| Regression | 21 (2.4%) | |
*Change considered on agreement of both primary readers.
†Change considered on agreement in 2/3 readings. Progression defined as worsening of at least one grade in at least one SIJ and ignoring a change from 0 to 1 over 2 years; regression defined as improvement of at least one grade in at least one SIJ and a baseline value of at least two in the improved joint.