Limitations
This study has limitations. First, the attrition rate differed between the 2 groups, which may bias the results. The sensitivity analysis using the worst-case scenario, per-protocol analysis, and IPCW analysis were introduced to the modified ITT analysis to overcome the attrition bias. Second, laboratory testing must be conducted to obtain the DAS28-CRP score. Whether patient self-assessment that does not require laboratory testing (eg, CDAI and Routine Assessment of Patient Index Data 3) could be developed into digital applications for clinical use is unknown. Third, cluster randomization is a more appropriate design due to the minimization of communication between the patients as well as modification of physician behavior, which make it harder to get significant effects. However, individual randomization could reduce treatment bias between study centers.