In an eHealth setting, to investigate intra- and interrater reliability and agreement of joint assessments and Disease Activity Score using C-reactive protein (DAS28-CRP) in patients with rheumatoid arthritis (RA) and test the effect of repeated joint assessment training.
Patients with DAS28-CRP ≤ 5.1 were included in a prospective cohort study (clinicaltrials.gov: NCT02317939). Intrarater reliability and agreement of patient-performed joint counts were assessed through completion of 5 joint assessments over a 2-month period. All patients received training on joint assessment at baseline; only half of the patients received repeated training. A subset of patients was included in an appraisal of interrater reliability and agreement comparing joint assessments completed by patients, healthcare professionals (HCP), and ultrasonography. Cohen's κ coefficients and intraclass correlation coefficients (ICC) were used for quantifying of reliability of joint assessments and DAS28-CRP. Agreement was assessed using Bland-Altman plots.
Intrarater reliability was excellent with ICC of 0.87 (95% CI 0.83-0.90) and minimal detectable change of 1.13. ICC for interrater reliability ranged between 0.69 and 0.90 (good to excellent). Patients tended to rate DAS28-CRP slightly higher than HCP. In patients receiving repeated training, a mean difference in DAS28-CRP of -0.08 was observed (limits of agreements of -1.06 and 0.90). After 2 months, reliability between patients and HCP was similar between groups receiving single or repeated training.
Patient-performed assessments of joints and DAS28-CRP in an eHealth home-monitoring solution were reliable and comparable with HCP. Patients can acquire the necessary skills to conduct a correct joint assessment after initial and thorough training. [clinicaltrials.gov (NCT02317939)].