Performance of Gout Impact Scale in a longitudinal observational study of patients with gout

Factors associated with change in health-related quality of life in people with gout: a 3-year prospective cohort study in primary care

OBJECTIVE

To describe factors associated with change in health-related quality of life (HRQOL) in people living with gout in primary care.

METHODS

In a UK prospective cohort study, adults with a diagnosis of gout registered with 20 general practices completed the Gout Impact Scale (GIS; scale 0-100), 36-item Short Form Physical Function subscale (PF-10; 0-100) and HAQ Disability Index (HAQ-DI; 0-3) via postal questionnaires at baseline and 6, 12, 24 and 36 months. Linear mixed modelling was used to investigate factors associated with changes in HRQOL over 3 years.

RESULTS

A total of 1184 participants responded at baseline (adjusted response 65.6%); 990 (83.6%) were male, with a mean age of 65.6 years (s.d. 12.5). A total of 818, 721, 696 and 605 responded at 6, 12, 24 and 36 months, respectively. Factors associated with worse disease-specific and generic HRQOL over 3 years were flare frequency (five or more flares; GIS subscales, PF-10), oligo/polyarticular flares (GIS subscales, PF-10, HAQ-DI), worse pain (GIS subscales, PF-10, HAQ-DI), body pain (GIS subscales, PF-10, HAQ-DI) and more severe depression (GIS subscales, PF-10, HAQ-DI) (P ≤ 0.05). More severe anxiety was associated with worse disease-specific HRQOL only (GIS subscales). Older age (PF-10), being female (PF-10, HAQ-DI) and BMI (HAQ-DI) were associated with worse generic HRQOL (P ≤ 0.05).

CONCLUSION

Gout-specific, comorbid and sociodemographic factors were associated with change in HRQOL over a 3-year period, highlighting people at risk of worse outcomes who could be targeted for interventions.

Translation, internal consistency, reliability and validity of the Thai version of Gout Assessment Questionnaire version 2.0 (GAQ 2.0)

OBJECTIVES

To translate the Gout Assessment Questionnaire version 2.0 (GAQ2.0) with Gout Impact (GI) Scale (GIS) into Thai and determine its psychometric property in gout patients with acute arthritis (acute arthritis group) and during the intercritical period (chronic gout group).

METHODS

Translation followed the ISPOR recommendations. Cronbach's α, intraclass correlation coefficient (ICC) and standardized response mean (SRM) were used to determine internal consistency, reliability and responsiveness to change, respectively. Correlations between GI subscales with generic health-related quality of life (HRQoL) questionnaires (SF-36, HAQ-DI and EQ-5D-5L) and gout clinical parameters were determined.

RESULTS

The acute arthritis group and the chronic gout group comprised 27 and 92 patients, respectively. Internal consistency was sufficient for all GI subscales (Cronbach's α = 0.80-0.98), reliability was moderate to good in most GI subscales (ICC = 0.54-0.88) and responsiveness to change was moderate to large in most GI subscales (SRM = 0.43-0.98). The GI subscales correlated better with SF-36 than HAQ-DI and EQ-5D-5L. In the acute arthritis group, the unmet gout treatment needs subscale showed large and moderate negative correlation with tophi and serum uric acid, respectively. In the chronic gout group, the gout concern overall subscale had statistically significant, moderate correlation with overall gout severity rated by the patients and number of gout attacks over the past year, while the well-being during attack subscale and total GIS score had statistically significant, moderate correlation with overall gout severity rated by the patients.

CONCLUSION

The Thai GAQ2.0 GIS showed acceptable internal consistency, reliability and responsiveness to change and correlated significantly with generic HRQoL questionnaires and clinical parameters. Key Points • The Thai GAQ2.0 GIS showed acceptable internal consistency, reliability and responsiveness to change in gout patients both during acute attack and during the intercritical period • The GI subscales showed significant correlation with SF-36 and HAQ questionnaires and gout clinical parameters in gout patients both during acute attack and during the intercritical period • The Thai GAQ2.0 GIS subscales should be used in conjunction with generic HRQoL for complete HRQoL assessment in gout patients.

Reducing Immunogenicity of Pegloticase With Concomitant Use of Mycophenolate Mofetil in Patients With Refractory Gout: A Phase II, Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE

Pegloticase is used for the treatment of severe gout, but its use is limited by immunogenicity. This study was undertaken to evaluate whether mycophenolate mofetil (MMF) prolongs the efficacy of pegloticase.

METHODS

Participants were randomized 3:1 to receive 1,000 mg MMF twice daily or placebo for 14 weeks, starting 2 weeks before receiving pegloticase and continuing while receiving intravenous pegloticase 8 mg biweekly for 12 weeks. Participants then received pegloticase alone from week 12 to week 24. The primary end points were the proportion of patients who sustained a serum urate level of ≤6 mg/dl at 12 weeks and the rate of adverse events (AEs). Secondary end points included 24-week durability of serum urate level ≤6 mg/dl. Fisher's exact test and Wilcoxon's 2-sample test were used for analyses, along with Kaplan-Meier estimates and log rank tests.

RESULTS

A total of 32 participants received ≥1 dose of pegloticase. Participants were predominantly men (88%), with a mean age of 55.2 years, mean gout duration of 13.4 years, and mean baseline serum urate level of 9.2 mg/dl. At 12 weeks, a serum urate level of ≤6 mg/dl was achieved in 19 (86%) of 22 participants in the MMF arm compared to 4 (40%) of 10 in the placebo arm (P = 0.01). At week 24, the serum urate level was ≤6 mg/dl in 68% of MMF-treated patients versus 30% of placebo-treated patients (P = 0.06), and rates of AEs were similar between groups, with more infusion reactions occurring in the placebo arm (30% versus 0%).

CONCLUSION

Our findings indicate that MMF therapy with pegloticase is well tolerated and shows a clinically meaningful improvement in targeted serum urate level of ≤6 mg/dl at 12 and 24 weeks. This study suggests an innovative approach to pegloticase therapy in gout.

Health-related quality of life assessed by Gout Impact Scale (GIS) in Chinese patients with gout

OBJECTIVE

The Gout Impact Scale (GIS) is a disease-specific health-related quality of life (HR-QoL) measurement for patients with gout. This study aimed to investigate the quality of life in Chinese patients with gout and potential risk factors for poorer HR-QoL by GIS.

METHODS

Adults with gout from February 2017 to February 2019 were invited to complete a questionnaire containing the GIS, social demographic characteristics, clinical information and gout-specific questions. Pearson/Spearman correlation and linear regression were used to analyze the data.

RESULTS

A total of 413 patients were included in the analysis (mean age, 51.85 years; 96.4% male). The mean (SD) score of GIS total was 56.79 ± 15.45. Worse gout-specific HR-QoL was associated with anxiety (p < .05), depression (p < .05) and fatigue (p < .05). The effectiveness and global satisfaction of Treatment Satisfaction Questionnaire for Medication (TSQM) were negatively related to each dimension of GIS. Age (B = -0.251, p = .013), fatigue (B = 1.850, p < .001) and depression (B = 9.068, p = .042) were independent predictors of GIS total score.

CONCLUSION

Gout-specific HR-QoL is impaired by social demographic and clinical characteristics, highlighting the importance of psychological factors (fatigue and depression) and patient-reported outcomes (patients' satisfaction and confidence in gout treatment). These findings suggest that more studies should focus on disease-specific HR-QoL.

Use of the Gout Impact Scale to Evaluate Quality of Life in Chinese Subjects with Gout: A Cross-Sectional Study

BACKGROUND To use a gout-specific quality of life (QoL) tool, the Gout Impact Scale (GIS), to evaluate characteristics of gout affecting QoL in subjects with gout. MATERIAL AND METHODS In this cross-sectional study, 169 individuals with gout completed the 24-item GIS and a general questionnaire regarding gout characteristics. The reliability and validity of the GIS were verified by Cronbach's a and exploratory factor analysis, respectively. The impact of gout characteristics on the QoL of subjects with gout was assessed by stepwise multiple regression analysis. RESULTS The 169 subjects with gout included 149 (88.2%) men and 20 (11.8%) women, of median age 43 years. The reliability of the GIS was appropriate (0.84-0.90), except for Gout Medication Side Effects (0.69) and Unmet Gout Treatment Need (0.59). Exploratory factor analysis showed that construct validity was acceptable, with a cumulative variance contribution rate of 5 common factors of 70.09% and factor loading >0.5 between each pair of items of the GIS. Univariate analysis showed that male sex was positively correlated with Well-being During Attack (p<0.05), and that source of medical expenses, current cigarette use and drinking were significantly correlated with Unmet Gout Treatment Need (p<0.05 each). A family history of gout, gout flares, and attack frequency were significantly correlated with total GIS, Well-being During Attack, and Gout Concern during Attack (p<0.05 each). Multivariate analysis suggested that history of gouty arthritis, acute attack and attack frequency had a considerable impact on QoL (p<0.05 each). CONCLUSIONS The GIS showed acceptable reliability and validity in identifying associations between poor QoL and gout characteristics.

An assessment of the psychometric properties of the Chinese version of the Gout Impact Scale

Objective: To assess the psychometric properties of the Chinese version of the Gout Impact Scale (GIS), a gout-specific HRQoL measure.Methods: This was a single-center, cross-sectional, observational survey of patients with gout recruited from the Taipei Medical University Hospital from November 2017 to April 2018. The respondents were recruited by convenience sampling. The reliability of the Chinese GIS was tested by Cronbach's α coefficient and adjusted using the Spearman-Brown prophecy formula. Content validity was assessed and confirmed by rheumatologists and pharmacists before the administration of the survey. Convergent validity was tested by Spearman correlation analysis to examine the association of the EQ-5D-5L with GIS total and subscale scores. Construct validity of the Chinese GIS was assessed by hypothesis testing.Results: A total of 311 patients were included in the analysis. The majority of these respondents were male (93.2%) with no comorbidities (69.5%) and they had a mean age of 52.9 (±14.2) years. The internal consistency of the Chinese GIS subscales was acceptable to excellent (Cronbach's α = 0.73-0.98) after adjusting to a 10 item scale with the Spearman-Brown prophecy formula. The GIS total and subscale scores were significantly associated with lower EQ-5D-5L scores ([-0.14] - [-0.27], p < .05). In addition, the GIS total and all subscale scores had a significant positive correlation with gout attack severity (r_s = 0.13-0.57, p < .05) and gout attack pain (r_s = 0.17-0.54, p < .01). Moreover, respondents' most recent sUA concentration was associated with both the GIS gout concern overall subscale (r_s = 0.13, p < .05) and the unmet gout treatment need subscale (r_s = 0.18, p < .01).Conclusions: The present study demonstrates that the Chinese version of the GIS shows good internal consistency and association with gout-related characteristics. Future studies may consider using this gout-specific instrument to assess the HRQoL of gout patients in Taiwan.

A systematic literature review of patient-reported outcome measures used in gout: an evaluation of their content and measurement properties

Background

Gout is a common, monosodium urate crystal-driven inflammatory arthritis. Besides its clinical manifestations, patients often also suffer from pain, physical impairment, emotional distress and work productivity loss, as a result of the disease. Patient-reported outcome measures (PROMs) are commonly used to assess these consequences of the disease. However, current instrument endorsements for measuring such outcomes in acute and chronic gout clinical settings are based on limited psychometric evidence. The objective of this systematic literature review was to identify currently available PROMs for gout, and to critically evaluate their content and psychometric properties, in order to evaluate the current status regarding PROMs for use in gout patients.

Methods

Systematic literature searches were performed in the PubMed and EMBASE databases. The methodological quality of included papers was appraised using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist, and evaluation of measurement properties (reliability, responsiveness, construct validity, floor and ceiling effects) was done in accordance with published quality criteria. Item content was appraised by linking health concepts to the International Classification of Functioning Disability and Health (ICF) framework.

Results

In total, 13 PROMs were identified, of which three were targeted specifically at gout patients. The majority of the PROMs were rated positively for content validity. For most instruments, limited evidence was available for construct validity and reliability. Instruments to assess pain scored well on responsiveness and floor and ceiling effects, but not much is known about their reliability in gout.

Conclusions

The physical functioning subscale of the SF-36v2 (Short Form-36 item version 2) is the only PROM that had sufficient supporting evidence for all its psychometric properties. Many of the commonly used PROMs in gout are currently not yet well supported and more studies on their measurement properties are needed among both acute and chronic gout populations.

Electronic supplementary material

The online version of this article (10.1186/s12955-019-1125-x) contains supplementary material, which is available to authorized users.

Gout Activity Score has predictive validity and is sensitive to change: results from the Nottingham Gout Treatment Trial (Phase II)

OBJECTIVES

To examine the predictive validity of the Gout Activity Score (GAS), its correlation with the Gout Impact Scale (GIS) and their sensitivity to change.

METHODS

Data from a clinical trial in which participants with one or more gout flares in the previous year were recruited from primary care and randomized to nurse-led or continuing usual care were used in this study. GAS and GIS were calculated as described, with higher scores indicating worse disease activity and quality of life, respectively. The correlation between GAS and GIS was examined using Spearman's correlation. Standardized response means (SRMs) were calculated to assess sensitivity to change. The association between GAS at baseline and the number of flares in the next 12 months was evaluated using Poisson regression. Data analyses were performed using STATA version 14, with P-values <0.05 being statistically significant.

RESULTS

There was low positive correlation between GAS and gout concern overall and unmet treatment need subscales of GIS (r = 0.34-0.45). Female sex associated independently with fewer gout flares, while increasing GAS, BMI and age associated independently with frequent flares. Of all the outcome measures examined, GAS was the most responsive to change (SRM 0.89 to -0.53). Of the GIS domains, the gout concern overall domain had the best sensitivity to change (SRM 1.06-0.01).

CONCLUSION

GAS is sensitive to change, has predictive validity and correlates with relevant domains of GIS such as gout concern overall. Additional independent validation of GAS is required before it can be adopted in clinical practice.

Long-term persistence and adherence on urate-lowering treatment can be maintained in primary care-5-year follow-up of a proof-of-concept study

Objectives

To evaluate the persistence and adherence on urate-lowering treatment (ULT) in primary care 5 years after an initial nurse-led treatment of gout.

Methods

One hundred gout patients initiated on up-titrated ULT between March and July 2010 were sent a questionnaire that elicited information on current ULT, reasons for discontinuation of ULT if applicable, medication adherence and generic and disease-specific quality-of-life measures in 2015. They were invited for one visit at which height and weight were measured and blood was collected for serum uric acid measurement.

Results

Seventy-five patients, mean age 68.13 years ( s . d . 10.07) and disease duration 19.44 years ( s . d . 13), returned completed questionnaires. The 5-year persistence on ULT was 90.7% (95% CI 81.4, 91.6) and 85.3% of responders self-reported taking ULT ⩾6 days/week. Of the 65 patients who attended the study visit, the mean serum uric acid was 292.8 μmol/l ( s . d . 97.2).

Conclusion

An initial treatment that includes individualized patient education and involvement in treatment decisions results in excellent adherence and persistence on ULT >4 years after the responsibility of treatment is taken over by the patient's general practitioner, suggesting that this model of gout management should be widely adopted.