Exploring Quality of Life Outcomes in Gout in Patients on a Treat-to-Target (TTT) Regime
Rowan Hart BMedSci (1), Amrey Krause PhD (2), Debbie Alexander BSc (1), Barbara Hauser PhD (1), Barbara Kuske PhD (1), Philip L Riches PhD (1)
Affiliation(s):
1. Rheumatic Diseases Unit, Western General Hospital, NHS Lothian
2. EPCC, The Bayes Centre, University of Edinburgh
Background: Gout is associated with reduced quality of life though frequent comorbidities and the intermittent nature of gout flares makes evaluation of the impact of disease challenging. Effective disease management with a treat-to-target (TTT) urate approach has shown sequential improvements in quality of life (QoL),1 however, no studies to our knowledge have prospectively evaluated the impact of gout flares with this approach
Objectives: To investigate QoL outcomes over time in patients on a TTT regime.
Status: This is an exploratory analysis of data from previously completed trials.
Methodology: We developed a smartphone app (GoutSMART), encouraging patients to maintain health diaries over time. Diaries were used to ensure participants were treated to target, but also prospectively captured QoL outcomes and timelines of flares. The approach was effective in achieving urate targets with a urate ≤0.36mmol/L achieved in 88% of active care participants at 52 weeks,2 and in 95% of participants at the end of a further 2 years of follow up.3 An exploratory analysis was undertaken in active care participants of both the feasibility and extension trials investigating quality of life over time. QoL outcomes were measured using EQ-5D-5L questionnaires, installed into the GoutSMART app. QoL entry timestamps were compared with flare entry timestamps and categorised into being either associated with a flare, up to 2 weeks after the end of a flare, or not associated with a flare, using Gaffo criteria4 to define a flare. To reduce bias from multiple entries we limited the analysis to the first entry per month for each participant. To address possible healthy survivor effect, we performed a sensitivity analysis limited to participants who completed the extension trial.
Findings: 40 active care participants entered the 12-month GoutSMART feasibility trial, and 30 completed the 2-year extension. Including all 40 participants, the total number of entries for analysis was 899 over 3 years. Excluding entries associated with a flare, from baseline to year 3, the average pain score significantly improved from 1.70 to 1.30 (p=0.0006). Global health improved from 75.22 at baseline to 87.08 in year 3 (p<0.0001) Changes in other domains did not reach significance (see Table 1). Very similar results were seen in a sensitivity analysis limited to 21 participants completing the feasibility trial (see Table 2). A paired analysis of 18 participants who entered both flare and convalescent QoL entries showed that QoL during a flare is significantly worse in all EQ-5D-5L domains apart from anxiety (see Table 3).
Significance: TTT urate implemented with close monitoring over 3 years results in a significant improvement in QoL even when scores are recorded outside of acute flares. Our results challenge the view that gout is only symptomatic during a flare and emphasise that gout is a chronic disease. In addition, we have evaluated the acute impact of flares on QoL, which cannot be fully captured when QoL scores are collected at fixed time points. Whilst limited by a lack of QoL data from patients on a standard care pathway our results provide further support for TTT in gout.
References:
1. Doherty M, Jenkins W, Richardson H, Sarmanova A, Abhishek A, Ashton D, Barclay C, Doherty S, Duley L, Hatton R, Rees F, Stevenson M, Zhang W; Efficacy and cost-effectiveness of nurse-led care involving education and engagement of patients and a treat-to-target urate-lowering strategy versus usual care for gout: a randomised controlled trial Lancet. 2018; 10156(392):1403-1412
2. Riches PL, Alexander D, Hauser B, Kuske B, Krause A. Evaluation of supported self-management in gout (GoutSMART): a randomised controlled feasibility trial. The Lancet Rheumatology. 2022 May 1;4(5):e320-8.
3. Riches PL, Alexander D, Brown C, Abbas H, Hart R, Krause A. Evaluation of continued 2-monthly or annual urate monitoring in gout: an extension of the GoutSMART randomised controlled feasibility trial. Explor Musculoskeletal Dis. 2024;2:509–20. https://doi.org/10.37349/emd.2024.00075
4. Gaffo AL, Dalbeth N, Saag KG, Singh JA, Rahn EJ, Mudano AS, et al. Validation of a Definition of Flare in Patients With Established Gout. Arthritis Rheumatol. 2018 Mar;70(3):462-467
