To assess patient-physician discordance in global assessment of disease activity in early axial spondyloarthritis (axSpA) over time and determinants of discordance.
DESIR (Devenir des Spondyloarthropathies Indifférenciées Récentes) is a French, multicentre, longitudinal cohort of patients with early inflammatory back pain suggestive of axSpA. Patient global assessment (PGA) and physician global assessment (PhGA) were rated with a 0-10 numerical rating scale, every 6 months during 2 years then at 3 years. Discordance was defined by the absolute difference |PGA-PhGA|≥3 (range 0-10) and was analysed at each visit. Determinants of (PGA-PhGA) were assessed at the visit level by a generalised linear mixed model.
A total of 702 patients were analysed at baseline (401 with complete data over 3 years): mean age 33.8±8.6 years, 379 (54.0%) female, mean symptom duration 18.1±10.5 months. Mean PGA values were always higher than mean PhGA values with a mean absolute difference of 1.8 points. At baseline, 202 (28.8%) patients had discordance mainly by PGA>PhGA; over 3 years the frequency of discordance was stable (range 25.5-28.8%). Discordance was not stable at the patient level, 118 (29.4%) patients were discordant once and 88 (22.0%) twice, and only 92 (22.9%) more than twice. Determinants of (PGA-PhGA) were spine pain (β=0.24, p<0.001) and fatigue (β=0.13, p<0.001).
Discordance concerned a quarter of patients with early axSpA. Over 3 years of follow-up, discordance did not decrease (no 'reference shift'). Discordance was not a stable trait, indicating discordance is not a patient characteristic.