Patients with rheumatoid arthritis presenting with mono- or oligo-arthritis and high VAS-ratings remain the most fatigued during 5 years of follow-up.

Objectives: The severity of fatigue in RA has improved very little in recent decades, leaving a large unmet need. Fortunately, not all RA patients suffer from persistent fatigue, but the subgroup of patients who suffer the most is insufficiently recognizable at diagnosis. As disease activity is partly coupled to fatigue, DAS components may associate with the course of fatigue. We aimed to identify those RA patients who remain fatigued by studying DAS components at diagnosis in relation to the course of fatigue over a 5-year follow-up period in two independent early RA cohorts.

Methods: In all, 1560 consecutive RA patients included in the Leiden Early Arthritis Cohort and 415 RA patients included in the tREACH trial were studied. Swollen joint count, tender joint count, ESR and Patient Global Assessment (PGA) [on a Visual Analogue Scale (VAS)] were studied in relation to fatigue (VAS, 0-100 mm) over a period of 5 years, using linear mixed models.

Results: Higher tender joint count and higher PGA at diagnosis were associated with a more severe course of fatigue. Furthermore, patients with mono- or oligo-arthritis at diagnosis remained more fatigued. The swollen joint count, in contrast, showed an inverse association. An investigation of combinations of the aforementioned characteristics revealed that patients presenting with mono- or oligo-arthritis and PGA ≥ 50 remained the most fatigued over time (+20 mm vs polyarthritis with PGA < 50), while the DAS course over time did not differ. This subgroup comprised 14% of the early RA population. Data from the tREACH trial showed similar findings.

Conclusion: The RA patients who remain the most fatigued were those characterized by mono- or oligo-arthritis and high PGA (VAS ≥ 50) at diagnosis. This understanding may enable early-intervention with non-pharmacological approaches in dedicated patient groups.