Subjective loss of clinical response to TNFi in axSpA relates to recurrence of MRI bone marrow oedema particularly with long-acting agents.

OBJECTIVES: Subjective loss of response immediately prior to routine TNFi therapy can occur in axial spondyloarthritis (axSpA). We investigated clinical outcomes in patients taking the first three licenced TNFis and correlated this with recurrence of MRI bone marrow oedema (MRI-BMO). METHODS: Proof-of-concept study including axSpA patients established on etanercept (ETA), adalimumab (ADA) or infliximab (IFX) reporting symptom deterioration prior to next dose. MRI/clinical data were collected prior to scheduled dose (v1), 4 days post-dose (v2) and at the time of patient-reported symptom return (v3). MRI spine/sacroiliac joints utilizing 3 T were scored using the semi-quantitative Leeds MRI scoring system. RESULTS: A total of 113 clinical assessments and MRIs were performed in 38 participants (ADA = 16, ETA = 12, IFX = 10), mean age 42.1 years ± 24.4(2SD, n = 38), 71.1% male (n = 27/38), 69.7% HLA-B27 positive (n = 23/33). At v1, all patients had high disease activity [ASDAS-CRP = 3 (2.7-3.7)] and 57.9% had MRI-BMO (number of MRI-BMO: ETA = 26, ADA = 59, IFX = 28). Improved clinical responses were seen at v2 [ASDAS-CRP -0.41(-0.81 - 0.30), P =0.018; BASDAI -0.58(-2.2 - 0.52), P =0.024]. Despite just a 4-day interval between v1 and v2, a numerical reduction in MRI-BMO lesions between v1/v2 was observed (ETA = -6, ADA = -10, IFX = -3). By v3, comparatively fewer new BMO lesions were detected in the ETA and ADA groups compared with IFX (ETA = -1, ADA = +3, IFX = +8), although the numbers were too small to enable testing for statistical significance. CONCLUSIONS: Short-lived fluctuations in MRI-BMO were commoner with longer-acting agents and corresponded with subjective loss of clinical response before next scheduled TNFi dose. Larger studies are needed to confirm the possible pathogenic implications of this phenomenon.

Diurnal variation of gait in patients with rheumatoid arthritis: The DIVIGN study.

BACKGROUND: Circadian variation of joint stiffness (morning stiffness) and its impact on functional ability are widely recognised in rheumatoid arthritis. Subsequent within-day variation of walking ability is important due to the increased availability of instrumented gait analysis. This study aimed to quantify diurnal variation of gait in patients with rheumatoid arthritis, and explore associations with disease characteristics. METHODS: Thirty one inpatients with rheumatoid arthritis walked at a self-selected speed along a GAITRite instrumented walkway 5 times during a single day. FINDINGS: Participants showed marked diurnal variation in gait, leading to a systematic variation throughout the day (F=19.56, P=<0.001). Gait velocity and stride length both increased, whereas the proportion of each gait cycle spent in stance phase or double support decreased, consistent with improving function throughout the day. Although absolute gait velocity correlated with disease characteristics, the magnitude of diurnal variation appeared to be independent of disease activity (rho=0.26, P=0.15), disease duration (rho=-0.19, P=0.324), and underlying functional ability (rho=0.09, P=0.65). INTERPRETATION: Although morning stiffness is well recognised in rheumatoid arthritis, this is the first time that its effect on gait has been quantified. Patients with rheumatoid arthritis exhibited a systematic change in walking ability throughout the day, which was independent of disease characteristics. These findings have important implications for the interpretation of existing data and the design of future studies. Repeat measures should be conducted at the same time of day to exclude the effects of diurnal variation.