Understanding prescribed dose in hand strengthening exercise for rheumatoid arthritis: A secondary analysis of the SARAH trial

OBJECTIVE: 1) To identify therapist or participant characteristics associated with prescribed dose of hand strengthening exercise in adults with rheumatoid arthritis and 2) To determine the impact of dose prescribed on outcome (hand function and grip strength). METHODS: Overall dose was calculated using area under the curve (AUC). Analysis 1 assessed the association between therapist professional background, therapist grade, baseline participant physical and psychological characteristics and prescribed dose. Analyses 2 and 3 estimated the relationship between prescribed dose and overall hand function and grip strength. Generalised estimating equation linear regression analysis was used. RESULTS: Analysis 1: Being treated by an occupational therapist (β = −297.0, 95% CI −398.6, −195.4), metacarpophalangeal joint deformity (β = −24.1, 95% CI −42.3, −5.9), a higher number of swollen wrist/hand joints (β = −11.4, 95% CI −21.6, −1.2) and the participant feeling downhearted and low all of the time (β = −293.6, 95% CI −436.1, −151.1) were associated with being prescribed a lower dose. Being treated by a grade 6 therapist (β = 159.1, 95% CI 65.7, 252.5), higher baseline grip strength (β = 0.15, 95% CI 0.02, 0.28) and greater participant confidence to exercise without fear of making symptoms worse (β = 18.9, 95% CI 1.5, 36.3) were associated with being prescribed a higher dose. Analyses 2 and 3: Higher dose was associated with greater overall hand function (β = 0.005, 95% CI 0.001, 0.010) and full‐hand grip strength (β = 0.014, 95% CI 0.000, 0.025) at 4‐month. CONCLUSION: Higher dose was associated with better clinical outcomes. Prescription of hand strengthening exercise is associated with both therapist and participant characteristics.