Trajectories of fatigue in actively treated patients with established rheumatoid arthritis starting biologic DMARD therapy.

OBJECTIVES

To define fatigue trajectories in patients with rheumatoid arthritis (RA) who initiate biological DMARD (bDMARD) treatment, and explore baseline predictors for a trajectory of continued fatigue.

METHODS

One-hundred and eighty-four patients with RA initiating bDMARDs were assessed at 0, 1, 2, 3, 6 and 12 months. Swollen and tender joint counts, patient reported outcomes (PROMs), blood samples and ultrasound examinations were collected at each time point. Fatigue was assessed by the fatigue Numeric Rating Scale (0-10) from the Rheumatoid Arthritis Impact of Disease (RAID) questionnaire. Clinically significant fatigue was predefined as fatigue ≥4. Three trajectories of interest were defined according to level of RAID fatigue: no fatigue (≤3 at 5/6 visits), improved fatigue (≥4 at start, but ≤3 at follow-up) and continued fatigue (≥4 at 5/6 visits). Baseline variables were compared between groups by bivariate analyses, and logistic regression models were used to explore baseline predictors of continued vs improved fatigue.

RESULTS

The majority of patients starting bDMARD therapy followed one of three fatigue trajectories, (no fatigue; n=61, improved; n=33 and continued fatigue; n=53). Patients with continued fatigue were more likely to be anti-citrullinated protein antibody and/or rheumatoid factor positive and had higher baseline PROMs compared to the other groups, while there were no differences between the groups for variables of inflammation including. Patient global, tender joint count and anxiety were predictors for the continued fatigue trajectory.

DISCUSSION: A trajectory of continued fatigue was determined by PROMs and not by inflammatory RA disease activity.