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The online version of this article (doi:10.1186/1477-7525-10-117) contains supplementary material, which is available to authorized users.
Savient Pharmaceuticals, Inc. provided funding for this study. AF was an employee of Savient during its execution. AG and JV are employees of Kantar Health, who conducted the study and contributed to manuscript preparation with funding from Savient. GN, TB, A-KT, and DK received funding from Savient for consulting purposes. In addition to funding from Savient, A-KT also received funding from Berlin-Chemie Menarini and Novartis for giving lectures and serving on Advisory Boards on the topic of gout; PK has served on speakers bureaus for Takeda, and has received research funding from Savient and ARDEA; DK serves as a consultant to ARDEA and Takeda, and is co-Principal Investigator for the 2012 American College of Rheumatology Guidelines for the management of gout. GN has served as a consultant for Ardea, Ipsen, Menarini, Metabolex, Novartis, and convenes the group to revise treatment guidelines for the British Society of Rheumatology. TB has received consultancy fees from the following companies, in the field of gout: Savient, Ipsen, Menarini, Takeda, Teijin, Sobi, Ardea Biosciences, Biocryst, Novartis, and Mayoli Spindler.
PK, GN, TB, A-KT, AF, and DK contributed to the design of the study and the writing of the manuscript. AG contributed to the design and analysis of the study, and the writing of the manuscript. JV contributed to the analysis and writing of the manuscript. All authors have read and approved the manuscript.
The prevalence of gout is increasing, and most research on the associated burden has focused on serum urate (sUA) levels. The present study quantifies the impact of the presence of tophi and frequency of acute gout attacks on health-related quality of life (HRQOL), productivity, and healthcare resource utilization.
Patients with self-reported gout (n = 620; 338 in US and 282 across France, Germany, and UK) were contacted based on inclusion in the 2010 US and EU National Health and Wellness Surveys (Kantar Health) and the Lightspeed Research ailment panel. Respondents were categorized into mutually-exclusive groups based on number of gout flares experienced in the past 12 months (0/don’t recall, 1–2, 3, 4–5, 6+), current presence of tophi (none, 1+, or not sure), and sUA level awareness (yes, no). HRQOL (SF-12v2), healthcare provider visits in the last 6 months, and work productivity and activity impairment (WPAI) were compared across groups.
Most patients were males, mean age of 61 years, who reported experiencing at least one acute gout flare in the past 12 months, and 12.3% (n = 76) reported presence of tophi. Among the 27.7% (n = 172) of patients who were aware of their sUA levels, higher sUA was associated with more flares and tophi. Decreased HRQOL was associated with more frequent flares and presence of tophi. In multivariable models predicting outcomes based on presence of tophi and number of flares, both flares (≥4) and tophi (≥1) were associated with HRQOL decrements on physical and mental component summary scores and health utilities (all p < 0.05), after adjustment for age, gender, and time since diagnosis. Flares were also associated with greater activity impairment.
Impairments associated with gout flares and presence of tophi, across patients in the US and EU, underscore the importance of effective management of this potentially curable condition.