A Delphi Exercise to Identify Characteristic Features of Gout — Opinions from Patients and Physicians, the First Stage in Developing New Classification Criteria

Foot and ankle muscle strength in people with gout: a two-arm cross-sectional study, Clinical Biomechanics (2015Biomechanics ( ), doi: 10.1016Biomechanics ( /j.clinbiomech.2015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT ABSTRACTBackground Foot and ankle structures are the most commonly affected in people with gout.However, the effect of gout on foot and ankle muscle strength is not well understood. The primary aim of this study was to determine whether differences exist in foot and ankle muscle strength for ankle plantarflexion, dorsiflexion, inversion and eversion between people with gout and age-and sex-matched controls. The secondary aim was to determine whether foot and ankle muscle strength was correlated with foot pain and disability.Methods Peak isokinetic concentric muscle torque was measured for ankle plantarflexion, dorsiflexion, eversion and inversion in 20 participants with gout and 20 matched controls at two testing velocities (30°/s and 120°/s) using a Biodex dynamometer. Foot pain and disability was measured using the Manchester Foot Pain and Disability Index (MFPDI).Findings Participants with gout demonstrated reduced muscle strength at both the 30°/s and 120°/s testing velocities for plantarflexion, inversion and eversion (p<0.05). People with gout also displayed a reduced plantarflexion-to-dorsiflexion strength ratio at both 30 o /s and 120 o /s (p<0.05). Foot pain and disability was higher in people with gout (p<0.0001) and MFPDI scores were inversely correlated with plantarflexion and inversion muscle strength at the 30°/s testing velocity, and plantarflexion, inversion and eversion muscle strength at the 120°/s testing velocity (all p<0.05).Interpretation People with gout have reduced foot and ankle muscle strength and experience greater foot pain and disability compared to controls. Foot and ankle strength reductions are strongly associated with increased foot pain and disability in people with gout.

Please cite this article as: Stewart S, Morpeth T, Dalbeth N, Vandal AC, Carroll M, Davidtz L, Mawston G, Otter S, Rome K, Foot-related pain and disability and spatiotemporal parameters of gait during self-selected and fast walking speeds in people with gout: a two-arm cross sectional study, Gait and Posture (2015), http://dx.doi.org/10.1016/j.gaitpost. 2015.11.004 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Method Gait parameters were measured using the GAITRite™ walkway in 20 gout participants and 20 age-and sex-matched controls during self-selected and fast walking speeds. Foot-pain and disability was measured using the Manchester Foot Pain and Disability Index (MFPDI) which contains four domains relating to function, physical appearance, pain and work/leisure.Results At the self-selected speed, gout participants demonstrated increased step time (p=0.017), and stance time (p=0.012), and reduced velocity (p=0.031) and cadence (p=0.013). At the fast speed, gout participants demonstrated increased step time (p=0.007), swing time (p=0.005) and stance time (p=0.019) and reduced velocity (p=0.036) and cadence (p=0.009). For participants with gout, step length was correlated with total MFPDI (r=-0.62, p=0.008), function (r=-0.65, p=0.005) and physical appearance (r=-0.50, p=0.041); stride length was correlated with total MFPDI (r=-0.62, p=0.008), function (r=-0.65, p=0.005) and physical appearance (r=-0.50, p=0.041); and velocity was correlated with total MFPDI (r=-0.60, p=0.011), function (r=-0.63, p=0.007) and work/leisure (r=-0.53, p=0.030). ConclusionGait patterns exhibited by people with gout are different from controls during both selfselected and fast walking speeds, even after adjusting for BMI and foot-pain. Additionally, gait parameters were strongly correlated with patient-reported functional limitation, physical appearance and work/leisure difficulties, while pain did not significantly influence gait in people with gout.

ObjectiveTo develop a new composite disease activity score for gout and provide its first validation.MethodsDisease activity has been defined as the ongoing presence of urate deposits that lead to acute arthritis and joint damage. Every measure for each Outcome Measures in Rheumatology core domain was considered. A 3‐step approach (factor analysis, linear discriminant analysis, and linear regression) was applied to derive the Gout Activity Score (GAS). Decision to change treatment or 6‐month flare count were used as the surrogate criteria of high disease activity. Baseline and 12‐month followup data of 446 patients included in the Kick‐Off of the Italian Network for Gout cohort were used. Construct‐ and criterion‐related validity were tested. External validation on an independent sample is reported.ResultsFactor analysis identified 5 factors: patient‐reported outcomes, joint examination, flares, tophi, and serum uric acid (sUA). Discriminant function analysis resulted in a correct classification of 79%. Linear regression analysis identified a first candidate GAS including 12‐month flare count, sUA, visual analog scale (VAS) of pain, VAS global activity assessment, swollen and tender joint counts, and a cumulative measure of tophi. Alternative scores were also developed. The developed GAS demonstrated a good correlation with functional disability (criterion validity) and discrimination between patient‐ and physician‐reported measures of active disease (construct validity). The results were reproduced in the external sample.ConclusionThis study developed and validated a composite measure of disease activity in gout. Further testing is required to confirm its generalizability, responsiveness, and usefulness in assisting with clinical decisions.