Fig 1.
Flowchart on patient inclusion and exclusion.
Abbreviations: IFX, infliximab; DAS28-ESR, the 28 joint disease activity score incorporating erythrocyte sedimentation rate; RA, rheumatoid arthritis.
Fig 2.
(A) Change in DAS28-ESR over time. The x-axis represents time after introduction of IFX. The y-axis represents values of DAS28-ESR. (B) Kaplan-Meier curve showing time to first response. Responders represent patients with “good or moderate response” based on the EULAR response criteria. The baseline (Day 0) was defined as the day of IFX introduction. (C) Kaplan-Meier curve showing time to loss of response. A change from responder to non-responder was defined as “loss of response.” The baseline (Day 0) was defined as the time point when the first response was observed. Patients who never showed any response during observation periods were excluded (n = 40). Abbreviations: DAS28-ESR, the 28 joint disease activity score incorporating erythrocyte sedimentation rate; EULAR, European League Against Rheumatism; IFX, infliximab.
Fig 3.
DAS28-ESR values and serum IFX concentrations in responders and non-responders.
(A) DAS28-ESR values at baseline and at IFX measurement point. Responders (open circle) represent patients with “good or moderate response” and non-responders (closed circle) represent those with “no response” based on the European League Against Rheumatism (EULAR) response criteria. (B) Serum IFX levels were measured in non-responders and responders. Each dot represents each patient’s serum IFX level and the bars indicate the median. Differences between the groups were assessed by Mann-Whitney U test. (C) Receiver operating characteristic (ROC) curve for the determination of the optimal IFX cut-off value for predicting persistent responder (area under the curve (AUC) = 0.87). Abbreviations: DAS28-ESR, the 28 joint disease activity score incorporating erythrocyte sedimentation rate; IFX, infliximab.
Table 1.
Baseline demographics and clinical characteristics of the patients.
Fig 4.
Changes in (A) CDAI, (B) SDAI, (C) CRP, and (D) HAQ-DI from the baseline to the IFX measurement point.
The left figures show the data of patients with IFX level <0.32 μg/mL (closed circles), and the right figures show the data of patients with IFX level ≥0.32 μg/mL (open circles). Each line corresponds to each patient. The data were analyzed by Wilcoxon signed-rank test. Abbreviations: CDAI, clinical disease activity index; CRP, C-reactive protein; DAS28-ESR, the 28 joint disease activity score incorporating erythrocyte sedimentation rate; HAQ-DI, physical disability by health assessment questionnaire-disability index; IFX, infliximab; SDAI, simplified disease activity index.
Table 2.
Number (percentages) of responders and non-responders at maximum effect and measurement point in each group.
Fig 5.
Comparison of serum IFX levels between ADA positive group (ADA (+)) and negative group (ADA (-)).
Each dot represents each patient’s serum IFX level and the bars indicate the median. Differences between groups were assessed by Mann-Whitney U test. Abbreviations: ADA, anti-drug antibody; IFX, infliximab.