Gout impacts on function and health-related quality of life beyond associated risk factors and medical conditions: results from the KING observational study of the Italian Society for Rheumatology (SIR)
1 Epidemiology Unit, Italian Society for Rheumatology, Via Turati 40, 20121, Milano, Italy
2 Division of Rheumatology, IRCCS Policlinico San Matteo Foundation, University of Pavia, Viale Golgi 19, 27100, Pavia, Italy
3 Clinica Reumatologica, Dipartimento di Medicina Interna e Specialità Mediche, University of Genova, V.le Benedetto XV 6, 16132, Genova, Genova, Italy
4 Rheumatology Unit, Department of Medical Sciences, University of Ferrara Azienda Ospedaliero-Universitaria S. Anna, Via Aldo Moro 8, 44124, Cona, Ferrara, Italy
5 Department of Molecular and Clinical Sciences - DISCLIMO, Polytechnic University of Marche, Via Tronto 10/a, 60020, Torrette di Ancona, Ancona, Italy
6 Rheumatology Unit, Department of Medicine DIMED, University of Padova, Via Giustiniani 2, 35122, Padova, Italy
7 Department of Public Health, Experimental and Forensic medicine, University of Pavia, Via Forlanini 2, 27100, Pavia, Italy
8 Department of Rheumatology AVC, Department of Biomedicine & Division of Rheumatology AOUC, Department of Medicine & Denothe Centre, University Florence, Largo Brambilla 3, 50134, Firenze, Italy
9 Rheumatology Unit, Azienda Ospedaliera San Camillo, Circ. Gianicolense 87, 00152 Roma, Italy
Arthritis Research & Therapy 2013, 15:R101 doi:10.1186/ar4281Published: 3 September 2013
Gout is the most prevalent arthritis and significantly impacts on function and quality of life. Given that gout associates with disabling comorbid conditions, it is not clear whether such a complex of diseases accounts for the increased disability or if gout may play a role by itself. This study aims to evaluate the specific influence of gout and disease-related features on functional disability and health-related quality of life (HRQoL) in patients with gout followed in rheumatology clinics.
A random sample of patients was drawn from clinical registries of 30 rheumatology clinics across Italy. Sociodemographic, general health and gout-specific variables were collected. Functional disability and HRQoL were assessed by the health assessment questionnaire (HAQ) and the Physical and Mental Component Summary scores (PCS and MCS) of the Short Form-36 (SF-36). Crude and adjusted ordinal logistic and linear regression models were applied to investigate the specific contribution of different variables on HAQ and SF-36 scores. Results are presented as odds ratio (OR) or mean difference (MD) and 95% confidence intervals.
Out of 446 patients with gout, 90% were males with a mean age of 63.9 years and median disease duration of 3.8 years; the majority of patients were overweight or obese, and with several comorbidities; 21.1% showed at least moderate disability; the PCS score was significantly lower than expected age- and gender-matched samples in the general population, while MCS score was not. After adjusting for potential sociodemographic and general-health confounders, gout-specific variables significantly impacted on HAQ, including polyarticular involvement OR 3.82 (1.63, 8.95), presence of tophi OR 1.92 (1.07, 3.43) and recent attacks OR 2.20 (1.27, 3.81). Consistent results were found for PCS. The impairment of PCS compared to the general population was limited to patients with features of chronic gout. MCS was only affected by recent attacks (MD -2.72 [-4.58, -0.86]) and corticosteroid treatment (-3.39 [-5.30,-1.48]).
The data from the KING study confirm that gout impacts on disability and provide evidence for an independent association of gout and gout-related features with functional outcome and HRQoL. This result supports the need to improve specific treatment in gout.