Patient-reported outcomes and disease activity in giant cell arteritis: a longitudinal registry-based study

OBJECTIVES: The objective of this registry-based cohort study was to evaluate longitudinal associations between disease activity measures and patient-reported outcomes (PROs) in GCA, and to assess whether specific PRO domains reflect clinically active disease. METHODS: Among all GCA patients registered in NorVas up to 12 December 2024, we selected patients who: 1) fulfilled the ACR 1990 classification criteria for GCA, 2) had two PROs recorded at least once, and 3) were included in NorVas at the time of diagnosis. HRQoL was assessed by RAND-12, using the physical (PCS) and mental composite scores (MCS) as outcomes. Visual analogue scales were used to assess pain, fatigue, and global disease assessment. The association between the PROs and disease activity were evaluated using linear mixed effects models. We assessed the PROs over time and the difference in PROs between active and inactive disease. RESULTS: We included 256 patients in the study with a median of 3 observations each, and a total of 1003 observations. All examined PROs showed a significant difference between active and inactive disease at baseline. Statistically and clinically significant differences were retained during follow-up for RAND-12-PCS (11.19 [5.67, 16.71]), pain (-12.64 [-18.58, -6.70]) and global assessment (-9.92 [-15.48, -4.35]). CONCLUSIONS: Our study demonstrates a consistent association between PROs and disease activity in GCA, most pronounced for the physical component of HRQoL, pain and global assessment. Patients with active disease showed statistically and clinically significant differences in PRO scores compared with those in remission, both at baseline and throughout follow‑up. While no single PRO domain can replace formal disease activity assessment, patterns across pain, fatigue and patient global measures may signal active disease and warrant clinical reassessment. Taken together, these findings indicate that selected combinations of PROs may serve as a useful adjunct in the monitoring of GCA.