Gout disease-specific quality of life and the association with gout characteristics

Jan D Hirsch1,4, Robert Terkeltaub4, Dinesh Khanna5, Jasvinder Singh6, Andrew Sarkin2, Micki Shieh2, Arthur Kavanaugh3, Susan J Lee3,41Skaggs School of Pharmacy and Pharmaceutical Sciences, 2Health Services Research, 3Center for Innovative  Therapy, Division of Rheumatology, Allergy, and Immunology, University of California San Diego, La Jolla, CA, USA; 4Veterans Administration San Diego Healthcare System, La Jolla, CA, USA; 5Department of Medicine/Rheumatology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; 6Department of Medicine/Rheumatology, Minneapolis VA Healthcare System, Minneapolis MN, USAPurpose: Assess the association of gout characteristics with health-related quality of life (HRQoL) using a new gout-specific HRQoL instrument, the Gout Impact Scale (GIS).Patients and methods: Gout patients completed the GIS (five scales [0–100 score each] representing impact of gout overall [three scales] and during an attack [two scales]) and other questions describing recent gout attacks, treatment, gout history, comorbidities, and demographics. Physicians confirmed gout diagnosis, presence of tophi, and most recent serum uric acid (sUA) level. Relationships between gout characteristics and GIS scores were examined using analysis of variance and correlation analyses.Results: The majority of patients were male (90.2%) with a mean age of 62.2 (±11.8) years. Approximately one-half (49.7%) reported ≥3 gout attacks in the past year and the majority (57.9%) reported experiencing gout-related pain between attacks. Patients had appreciable concern about their gout (“gout concern overall” scale, 63.1 ± 28.0) but believed their treatment was adequate (“unmet gout treatment need” scale (38.2 ± 21.4) below scale mid-point). Significantly worse GIS scores were associated with increasing attack frequency and greater amount of time with pain between attacks (most scales, P < 0.001). Common objective measures such as sUA level, presence of tophi and the number of joints involved in a typical attack did not appear to be good indicators of the impact of gout on the patients’ HRQoL.Conclusion: Attack frequency and gout pain between attacks were important correlates of patients’ ratings of gout impact on their HRQoL. Further studies are needed to determine the minimal important difference for each GIS scale and interpret our results relative to other patient populations with gout.Keywords: Gout impact scale, GIS, patient-reported outcome