Patient-reported 28 swollen and tender joint counts accurately represent RA disease activity and can be used to assess therapy responses at the group level.

Objective. Formal joint assessments are critically important to improve rheumatological care of patients with RA. The aim of this study was to determine the usefulness of patient-recorded 28 tender joint counts (TJCs) and swollen joint counts (SJCs) using a tablet personal computer and to explore the possibility of using patient-recorded data to calculate 28-joint DAS (DAS-28) and EULAR response. Methods. Forty-seven patients were included before initiation of adalimumab therapy and assessed at baseline and after 3 months. SJC and TJC were registered by the patients and thereafter by an experienced rheumatology specialist. Changes were correlated using Spearman's rank correlation test. Results. The correlations between SJC and TJC derived by the physician and the patient at baseline were excellent (r = 0.78 and 0.87, respectively P < 0.01 for both). After 3 months, the correlations were less strong (0.645 and 0.745, respectively, P < 0.001 for both). When using the patient-derived SJC/TJC for calculation of the DAS-28 (patDAS-28), similar values were obtained, and correlations between DAS-28 and patDAS-28 were excellent (r = 0.91 at baseline, r = 0.90 at 3 months). According to the EULAR response criteria, the percentage of responders at the group level was nearly identical, although there was some disagreement at the individual level when DAS-28 and patDAS-28 were used to determine response to therapy. Conclusion. Patient-reported SJC and TJC can in research settings be used instead of physician-reported ones. Patient-derived SJC and TJC may also make it possible for rheumatologists to obtain quantitative joint count recordings much more frequently than is feasible for traditional joint counts.