Mylène Jansen

KIDA performance in severe OA 221 11 The ICCs in most cases were good-excellent and the differences (Δ), SD and SDD were small compared to the overall means. However, for the osteophytes the ICCs were moderate (except for the lateral tibia with a good ICC) and the differences and SDDs were relatively high compared to the mean values. Furthermore, all parameters showed a systematic difference (bias) between readings, as indicated by the 95%CI of the difference. The direction of this bias differed and, except for osteophytes, was small relative to the absolute value. Results for severe radiographs reanalyzed within one month The Bland-Altman plots for the same set of 3 parameters as shown in Figure 2, but evaluated in the 98 radiographs that were reanalyzed within a month, are shown in Figure 3. All other plots for these 98 radiographs can be found in Supplementary Figures S6 – 10. For these analyses, none of the plots showed significant systematic differences between the 2 readings. Figure 3 : Bland-Altman plots the 98 radiographs that were analyzed twice within a month, for (A) the bone density of the medial tibia in mm aluminum equivalent (mm Al eq), (B) the minimum joint space width in mm and (C) the osteophyte area of the lateral femur in mm 2 . The analysis parameters for these radiographs are shown in Table 2. The ICCs were excellent for most parameters, for 4 parameters the ICC was good, 3 of them being osteophyte parameters. Again, in most cases, differences (Δ), SD and SDD were small compared to the overall means for all parameters, although not for the osteophytes. Clearly less parameters showed significant bias, as indicated by the 95%CI of the differences. Similar to the observed bias for comparisons over the longer time period, the tibia medial bone density, femoral osteophytes, and mean lateral JSW showed significant positive bias, while the joint angle showed negative bias.