Reproducibility of IBD-Control summary scores for stable patients
| Instrument score (scale) | Mean difference (Visit 2—Visit 1) | SD of difference | Intraclass correlation (95% CI) |
|---|---|---|---|
| (A) Patients returning at 2 weeks (test-retest group)* | |||
| IBD-Control-8 subscore (0–16) | −0.45 | 1.81 | 0.97 (0.90 to 0.99) |
| IBD-Control-VAS (0–100) | +2.25 | 9.79 | 0.96 (0.88 to 0.99) |
| (B) Patients returning for a scheduled clinic visit (routine care group)† | |||
| IBD-Control-8 subscore (0–16) | 0.00 | 3.72 | 0.87 (0.71 to 0.94) |
| IBD-Control-VAS (0–100) | −0.56 | 23.00 | 0.81 (0.58 to 0.91) |
*Data for 13 patients responding ‘not changed’ to the IBD-Control transition question (‘Over the past 2 weeks have your bowel symptoms been getting worse, getting better or not changed’) and with stable UK-IBD-Qol total scores (<10-point change between two visits).
†Data for 32 patients with a stable (unchanged) physician global assessment rating between two visits (mean interval between visits 131 days).
Two-way fixed effects model for consistency, p<0.001.
IBD, inflammatory bowel disease; QoL, quality of life; VAS, visual analogue scale.