Predictive validity of candidate remission definitions for good outcome in both radiographic damage and HAQ*
| Prevalence of good outcome in patients | ||||
|---|---|---|---|---|
| Candidate remission definition | In remission | Not in remission | Positive likelihood ratio (95% CI) | p† |
| TJC28, SJC28, CRP ≤1 | 46 (22/48) | 17 (51/301) | 3.2 (1.9 to 5.3) | <0.0001 |
| TJC28, SJC28, CRP, PhGA ≤1 | 55 (18/33) | 17 (55/315) | 4.5 (2.4 to 8.5) | <0.0001 |
| TJC28, SJC28, CRP, PtGA ≤1 | 66 (19/29) | 17 (54/320) | 7.2 (3.5 to 14.8) | <0.0001 |
| TJC28, SJC28, CRP, pain ≤1 | 60 (18/30) | 17 (55/319) | 5.7 (2.9 to 11.2) | <0.0001 |
| TJC28, SJC28, CRP, PhGA, PtGA ≤1 | 68 (17/25) | 17 (56/323) | 8.0 (3.6 to 17.8) | <0.0001 |
| TJC28, SJC28, CRP, PhGA, pain ≤1 | 64 (16/25) | 18 (57/323) | 6.7 (3.1 to 14.5) | <0.0001 |
| TJC28, SJC28, CRP, PtGA, pain ≤1 | 64 (18/28) | 17 (55/321) | 6.8 (3.3 to 14.1) | <0.0001 |
| TJC28, SJC28, CRP, PhGA, PtGA, pain ≤1 | 67 (16/24) | 18 (57/324) | 7.5 (3.4 to 16.9) | <0.0001 |
| DAS28 <2.6 | 38 (13/34) | 18 (28/154) | 2.2 (1.2 to 4.0) | 0.01 |
| DAS28 <2.0 | 56 (5/9) | 20 (36/179) | 4.5 (1.3 to 15.9) | 0.01 |
| SDAI ≤3.3‡ | 56 (19/34) | 17 (54/314) | 4.8 (2.6 to 8.9) | <0.0001 |
| Definitions without CRP (for clinical practice) | ||||
| TJC28, SJC28, PhGA, PtGA ≤1 | 68 (21/31) | 17 (53/321) | 7.9 (3.9 to 16.0) | <0.0001 |
| TJC28, SJC28, PtGA ≤1 | 66 (23/35) | 16 (51/318) | 7.2 (3.8 to 13.9) | <0.0001 |
| CDAI ≤2.8§ | 63 (22/35) | 16 (52/317) | 6.4 (3.4 to 12.0) | <0.0001 |
↵* Values in the first two columns are percentages, with absolute proportions shown in parentheses. Presence or absence of remission, defined according to the given candidate definition, was measured at 6 months after baseline, using combined data from methotrexate-alone treatment groups in three trials37 40 41 (limited to patients with complete data over 2 years). Good radiographic outcome was defined as a change of ≤0 in Sharp/van der Heijde scores between 12 and 24 months after baseline; good outcome on the HAQ was defined as a change of ≤0 and a score of ≤0.5 at both the 12-month and 24-month time points. CRP is in mg/dl.
↵† From χ2 analysis using logistic regression, in which the independent variable was remission (based on the given candidate definition) and the dependent variable was the combination of radiographic and HAQ stability.
↵‡ The Simplified Disease Activity Index (SDAI) is the simple sum of the TJC (using 28 joints), SJC (using 28 joints), patient global assessment (0-10 scale), physician global assessment (0-10 scale), and CRP level (mg/dl).
↵§ The Clinical Disease Activity Index (CDAI) is the same as the SDAI, except CRP is not included.
CDAI, Clinical Disease Activity Index; CRP, C reactive protein; DAS28, 28-joint Disease Activity Score (see Table table 1 for other definitions); PhGA, physician/observer global assessment; PtGA, patient global assessment; SDAI, Simplified Disease Activity Index; SJC, swollen joint count; TJC, tender joint count.