The natural course of health-related quality of life in patients with clinically suspect arthralgia: a longitudinal study in progressors and non-progressors to rheumatoid arthritis.

Individuals with clinically suspect arthralgia (CSA) are at risk of developing rheumatoid arthritis (RA). It is unknown whether CSA patients have a deprived health-related quality-of-life (HRQoL), how this develops over time, and whether it differs between those who develop RA and those who do not. Using three unique cohorts, we explored the course of HRQoL in CSA patients and after inflammatory arthritis (IA, in this case defined as being either undifferentiated arthritis (UA) or RA) diagnosis. Longitudinal cohort data were used from two CSA cohorts (n = 507) and an IA cohort (n = 282). HRQoL as measured with the EuroQol-5 Dimensions-5 levels (EQ-5D-5 L) questionnaire was compared between CSA patients who develop IA and who do not. We estimated the course of EQ-5D-5 L scores with linear mixed models. In addition, autoantibody-positive and -negative patients were compared. As patients developed IA, their mean EQ-5D-5 L scores deteriorated with 0.12 points (0.03-0.22) over two years, with mobility and usual activities most impacted. Self-care and pain/discomfort were already impacted longer before the diagnosis. Treatment initiation after IA diagnosis showcased an improvement of 0.13 (0.09-0.16) points within 4 months, particularly in the self-care and pain/discomfort dimensions, stabilizing thereafter. In CSA patients who did not develop IA, HRQoL remained stable with a minor improvement of 0.05 (0.02-0.08) points over 2 years. Autoantibody-status had no impact. HRQoL deteriorates before IA diagnosis but improves after treatment initiation. CSA patients who do not develop IA experience stable HRQoL. These findings suggest that early intervention in CSA could prevent deterioration in HRQoL, supporting the potential value of treatment in the CSA phase.