Changes in physical activity measured by accelerometry following initiation of DMARD therapy in rheumatoid arthritis.
OBJECTIVE
The aim of this study was to assess changes in habitual physical activity levels in response to DMARD therapy in RA patients.


METHODS
Eighteen drug-naive RA patients were prospectively assessed at baseline and following 3 months of DMARD therapy for habitual physical activity by accelerometry, disease activity using the clinical disease activity index (CDAI) and functional disability using the modified HAQ (mHAQ). Baseline physical activity was also compared with an equal number of healthy control participants matched for age, sex and BMI.


RESULTS
Following 3 months of DMARD therapy, in parallel with significant improvements in CDAI scores (P < 0.001) and HAQ scores (P < 0.001), accelerometry measures in the RA cohort showed that the average activity counts in sedentary thresholds decreased (P = 0.012), while average activity counts within higher-intensity thresholds increased (P = 0.039). Multiple regression analysis showed that the change in moderate activity was associated with a decrease in CRP (β = - 0.922, P = 0.026) while the decrease in sedentary activity and increase in moderate activity were associated with decreased morning stiffness of the joints (β = 0.694, P = 0.035 and β = -0.927, P = 0.024, respectively). At baseline, RA patients were less physically active than control participants in the morning (P = 0.048) and in the late afternoon (P = 0.016), but these diurnal differences were no longer significant after the DMARD intervention.


CONCLUSIONS
These findings suggest that accelerometry may potentially be a viable objective method of assessing changes in physical disability in response to various disease-modifying drugs.
School of Physiology, Faculty of Health Science, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2001, South Africa. alessandraprioreschi@gmail.com.
Alessandra
A
Prioreschi
Bridget
B
Hodkinson
Mohammed
M
Tikly
Joanne A
JA
McVeigh
D061725:Accelerometry / Q000379:methods*; D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000503:physiopathology*; D016022:Case-Control Studies; D002940:Circadian Rhythm / Q000502:physiology; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007596:Joints / Q000503:physiopathology; D008137:Longitudinal Studies; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology; D012720:Severity of Illness Index; D016896:Treatment Outcome
D018501:Antirheumatic Agents
DMARD therapy; accelerometry; physical activity; rheumatoid arthritis