Background Gout is the most prevalent arthritis and significantly impacts on function. Despite the availability of effective treatments, suboptimal management and excess of functional disability are frequently reported for gouty patients. The identification of disease-related prognostic factors may help in filling this gap on the management of patients with gout.
Objectives To explore disease-related factors associated with functional disability in Italian patients with gout.
Methods This is retrospective analysis of an ongoing multicentre cohort study including patients with prevalent clinically diagnosed gout from 30 rheumatology practices in Italy (Kick-off of the Italian Network for Gout, KING, promoted by SIR) recruited from June 2011 and January 2012. Participants were centrally selected from clinical registers by random sampling. All patients underwent full clinical evaluation. Collected variables included: socio-demographics, life-styles, co-morbidity index and treatments. Gout-related variables included: diagnosis, duration, pattern of disease, previous and current treatment, joint examination and serum uric acid (sUA) concentration. Outcomes were measured using HAQ-DI (primary) and Physical Component Sumary Score (PCS) from SF-36 (secondary). Predictors were identified from an a priori list and selected from different domains (sociodemographics, comorbidities, lifestyles, pattern of disease and treatment). The relationship between predictors and outcomes was modelled using linear regression models. Results are presented ad regression coefficients [95% confidence intervals, CI] adjusted for age and gender.
Results A total of 450 patients were included in the analyses. M:F ratio was 9:1 M:F, mean (SD) age 63.7 (11.6) years and median (IQR) disease duration 3.4 (1.4-9.7) years; 91% fulfilled Wallace classification criteria for gout, 19.8% had tophaceous and 17.9% polyarticular disease; 54.9% had sUA>6mg/dl and 81% were on treatment with xantine-oxidase inhibitors (70% allopurinol and 11% febuxostat); 47.3% of patients had at least mild functional disability according to HAQ (mean [SD] HAQ 0.46 [0.60]); standardized mean (SD) PCS was 43.8 (0.57).
Factors associated with higher HAQ-DI score were: comorbidity index (0.03 [0.02,0.05]), BMI (0.02 [0.01,0.03]) education (-0.19 [-0.30,-0.08]), polyarticular disease (0.37 [0.18,0.56]), tophaceous disease (0.24 [0.09,0.38]), last year attacks (0.03 [0.02,0.05]), sUA (mg/dl) after treatment (0.04 [CI 0.01,0.09]), number of TJC-68 (0.04 [0.03,0.05]), SWJ-66 (0.07 [0.05,0.09]).
Secondary analyses swowed the following factors associated with PCS score: comorbidity index (-0.91 [-0.12,-0.62]), BMI (-0.35 [-0.61,-0.08]) education (2.7 [0.66,4.73]) polyarticular disease (-5.34 [-8.8,-1.85]), tophaceous disease (-4.24 [-6.9, -1.53]), last year attacks (-0.81 [-1.12,-0.5]), sUA (mg/dl) after treatment (-1.33 [-2.1, -0.55]), number of TJC-68 (-0.6 [-0.79,-0.41]), SJC-66 (-1.39 [-1.78, -1.0]).
Conclusions Patients with gout show a significant functional impairment and suboptimal management even in rheumatological setting. This poor disease control reflects on higher disease-related functional impairment.
Disclosure of Interest None Declared