Minimally important differences of the gout impact scale in a randomized controlled trial

Reliability and Validity of the Korean Version of the Gout Impact Scale

BACKGROUND

The Gout Impact Scale (GIS), part of the Gout Assessment Questionnaire 2.0, measures gout-specific health-related quality of life (HRQOL). This study aimed to translate the GIS into Korean and validate the Korean version (K-GIS) using generic HRQOL measures.

METHODS

The GIS was translated into Korean and back-translated into English. We asked patients aged 18 years or older who met the 2015 gout classification criteria to fill out the questionnaires (from January 2022 to June 2022); the K-GIS (5 scales [0-100 scores each]), along with the Korean version of Health Assessment Questionnaire (HAQ) and EuroQol-5 dimension (EQ-5D). We investigated the internal consistency, construct validity, and discriminative validity for gout characteristics of K-GIS. The K-GIS form was administrated to patients 4 weeks later to assess the test-retest reliability using the intraclass correlation coefficient (ICC).

RESULTS

One hundred patients completed the questionnaire. The mean ± standard deviation age of the patients was 53.0 ± 15.1 years, and 99.0% of the patients were men. All scales had high degree of internal consistency (Cronbach's α = 0.59 to 0.96) and test-retest reliability (n = 18, ICC = 0.83 to 0.94, all P < 0.001), except for unmet gout treatment needs. Weak-to-moderate correlations were observed between the K-GIS scales and HAQ or EQ-5D (r = 0.21 to 0.46). The K-GIS scores were significantly higher in the presence of bone erosion, absence of urate-lowering therapy, serum urate levels > 6 mg/dL, frequent gout flares in the past year, and fewer comorbidities. In contrast, neither the HAQ nor the EQ-5D could discern these subsets of patients.

CONCLUSION

The K-GIS is a reliable and valid HRQOL measure for patients with gout. Higher K-GIS scores were associated with clinical characteristics leading to unfavorable outcomes, which were not demonstrated by the HAQ and EQ-5D.

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.

Gout management and outcomes during established COVID-19 pandemic in 2020-2021: a cross-sectional Internet survey

Objective

To assess the management of gout in established COVID-19 pandemic.

Methods

We assessed medication use, health care utilization, gout-specific health-related quality of life (HRQOL), psychological distress using Patient Health Questionnaire-4 (PHQ-4), resilience, illness perception, and health literacy in people with physician-diagnosed self-reported gout in established COVID-19 pandemic in a cross-sectional Internet survey.

Results

Among the 130 survey respondents with gout, the mean age was 62.8 years, 65% were male, 83% were White, 59% were prescribed urate-lowering therapy (ULT), and health literacy was adequate in 80%. A third of survey respondents reported more difficulty with their gout management since September 2020. Gout-specific HRQOL deficits were evident. Moderate-severe psychological distress was seen in 22%, and resilience score was 6.5 [standard deviation (SD), 1.9; range, 0-8]. Adjusted for age and sex, compared with no/mild psychological distress, moderate-severe psychological distress was associated with significantly higher odds ratio (OR; 95% confidence interval) of more difficulty with (1) getting health care for gout in clinic, 3.7 (1.0, 13.2); emergency room/urgent care, 8.1 (1.4, 45.0); and in the hospital, 9.8 (1.6, 59.6); (2) getting gout flares treated, 6.6 (1.6, 26.8); (3) avoiding gout complications, 4.5 (1.2, 16.7); and (4) daily activities at home, 4.2 (1.3, 14.1), and performing work, 4.1 (1.2, 13.6).

Conclusion

Respondents with gout reported health care gaps, low rates of ULT prescription, high psychological distress, and HRQOL deficits during established COVID-19 pandemic. Moderate-severe psychological distress was associated with difficulties in health care access and gout management. Interventions to address these challenges in gout management are needed.

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.

SToRytelliing to Improve Disease outcomes in Gout (STRIDE-GO) in African American veterans with gout: a trial study protocol

Objective

Medication adherence in gout is suboptimal, and the lack of effective interventions to address it presents a huge challenge. Medication adherence and gout outcomes are worse in racial/ethnic minorities. The objective of this paper was to provide the details of the study protocol for randomized, controlled trial (RCT) in African Americans (AAs) with gout that will test the effectiveness of a culturally appropriate gout storytelling intervention.

Methods

The SToRytelliing to Improve Disease outcomes in Gout (STRIDE-GO) study will be a 12-month, multicenter, open-label RCT that will assess the effect of a culturally appropriate gout storytelling in at least 300 AA veterans with gout. Participants will be randomized to gout-storytelling intervention vs. a stress reduction video in a 1:1 ratio. The primary outcome is urate-lowering therapy (ULT) adherence measured with MEMSCap™, an electronic monitoring system (efficacy, 6 months; sustenance of efficacy, 12 months). Secondary outcomes include gout flares, serum urate (SU), gout-specific health-related quality of life [HRQOL], self-reported ULT adherence, patient satisfaction with treatment, and patient understanding of the intervention. AA veterans with gout who met the 1977 Preliminary American College of Rheumatology (ACR) classification criteria for gout, currently prescribed an oral ULT medication (allopurinol or febuxostat) for at least 6 months, and not using a pillbox to redistribute their medications, will be invited to an in-person study visit. After the study coordinators obtain informed consent, and ensure that participants meet the inclusion criteria, the eligible participants will be provided with their current ULT in a MEMSCap™ bottle for the 1-month run-in period and asked to return to the clinic in 1 month. ULT adherence with MEMSCap™ will be recorded at a 1-month return visit. Interested participants will complete the baseline assessments, randomized using the computerized system to either gout-storytelling intervention or a stress reduction intervention video arm and watch the respective video in-clinic. Patients will be interviewed on the phone at 2 and 4 months regarding the viewing of the videos at home at each time. Participants will be assessed in-clinic at 3, 6, 9, and 12 months; MEMSCap™ data and patient surveys will be captured at each visit. For any missed visit, assessments will be completed on the phone and MEMSCap™ data captured at the next in-clinic visit.

Discussion

The study will assess the efficacy of a behavioral intervention to improve ULT adherence in minority populations with gout.

Trial registration

ClinicalTrials.gov NCT 02741700. Registered on 14 September 2018

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05847-9.

SToRytelling to Improve Disease outcomes in Gout (STRIDE-GO): a multicenter, randomized controlled trial in African American veterans with gout

BACKGROUND

Urate-lowering therapy (ULT) adherence is low in gout, and few, if any, effective, low-cost, interventions are available. Our objective was to assess if a culturally appropriate gout-storytelling intervention is superior to an attention control for improving gout outcomes in African-Americans (AAs).

METHODS

In a 1-year, multicenter, randomized controlled trial, AA veterans with gout were randomized to gout-storytelling intervention vs. a stress reduction video (attention control group; 1:1 ratio). The primary outcome was ULT adherence measured with MEMSCap™, an electronic monitoring system that objectively measured ULT medication adherence.

RESULTS

The 306 male AA veterans with gout who met the eligibility criteria were randomized to the gout-storytelling intervention (n = 152) or stress reduction video (n = 154); 261/306 (85%) completed the 1-year study. The mean age was 64 years, body mass index was 33 kg/m2, and gout disease duration was 3 years. ULT adherence was similar in the intervention vs. control groups: 3 months, 73% versus 70%; 6 months, 69% versus 69%; 9 months, 66% versus 67%; and 12 months, 61% versus 64% (p > 0.05 each). Secondary outcomes (gout flares, serum urate and gout-specific health-related quality of life [HRQOL]) in the intervention versus control groups were similar at all time points except intervention group outcomes were better for the following: (1) number of gout flares at 9 months were fewer, 0.7 versus 1.3 in the previous month (p = 0.03); (2) lower/better scores on two gout specific HRQOL subscales: gout medication side effects at 3 months, 32.8 vs. 39.6 (p = 0.02); and unmet gout treatment need at 3 months, 30.9 vs. 38.2 (p = 0.003), and 6 months, 29.5 vs. 34.5 (p = 0.03), respectively.

CONCLUSIONS

A culturally appropriate gout-storytelling intervention was not superior to attention control for improving gout outcomes in AAs with gout.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov NCT02741700.

Gout management and outcomes during the COVID-19 pandemic: a cross-sectional internet survey

Aim:

We aimed to assess the gout management during the COVID-19 pandemic.

Methods:

We assessed medication use, healthcare utilization, gout-specific health-related quality of life (HRQoL) on the Gout Impact Scale (GIS), psychological distress using the patient health questionnaire-4 (PHQ-4), and resilience in people with self-reported physician-diagnosed gout during the COVID-19 pandemic in a cross-sectional Internet survey.

Results:

Among the 122 survey respondents with physician-diagnosed gout, 82% were prescribed urate-lowering therapy (ULT) and 66% were taking ULT daily; mean age was 54.2 years [standard deviation (SD), 13.8], 65% were male, and 79% were White. More regular use of gout medication was reported during the COVID-19 pandemic: allopurinol, 44%; colchicine, 37%; non-steroidal anti-inflammatory drugs, 36%. Gout flares were common: 63% had ⩾1 gout flare monthly; 11% went to emergency room/urgent care; and 2% were hospitalized with gout flares. Between 41% and 56% of respondents reported more difficulty with gout management and related functional status related to COVID-19; 17–37% had difficulty with healthcare access for gout. HRQOL deficits were evident for gout concern overall, 79.4 (SD, 25); unmet gout treatment need, 64.5 (SD, 27.1); and gout concern during flare, 67.3 (SD, 27.1); but less so for gout medication side effects, 48.9 (SD, 27.4). Psychological distress was moderate in 19% and severe in 15% (mild, 22%; normal, 45%). Resilience score on Connor–Davidson Resilience Scale (CD-RISC2) was 5.6 (SD, 1.8; range 0–8). Compared with no/mild psychological distress, moderate–severe psychological distress during the COVID-19 pandemic was significantly associated with more difficulty getting gout medication filled (p = 0.02), flares treated (p = 0.005), and receiving gout education (p = 0.001).

Conclusion:

Healthcare gaps, psychological distress, and HRQoL deficits were commonly reported by people with gout during the COVID-19 pandemic. Interventions to address these challenges for people with gout during the COVID-19 pandemic are needed.

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.

Serum Uric Acid and the Risk of Incident and Recurrent Gout: A Systematic Review

OBJECTIVE

Lowering serum uric acid (SUA) levels can essentially cure gout; however, this is not widely practiced. To summarize epidemiologic evidence related to this causal link, we conducted a systematic review of the published literature reporting the association between SUA level and incident and recurrent gout (i.e., gout flares).

METHODS

We systematically searched Medline, EMBASE, and the Cochrane Database of Systematic Reviews using separate search strategies for incident gout and recurrent gout. We screened 646 abstracts to identify 8 eligible articles reporting gout incidence and 913 abstracts to identify 18 articles reporting recurrent gout.

RESULTS

For both gout incidence and recurrence, a graded trend was observed where the risk was increased with higher SUA levels. Gout incidence rates per 1000 person-years from population-based studies ranged from 0.8 (SUA ≤ 6 mg/dl) to 70.2 cases (SUA ≥ 10 mg/dl). Recurrent gout risk in clinical cohorts ranged from 12% (SUA ≤ 6 mg/dl) to 61% (SUA ≥ 9 mg/dl) among those receiving urate-lowering therapy (ULT), and 3.7% (SUA 6-7 mg/dl) to 61% (SUA > 9.3 mg/dl) after successful ULT. Retrospective database studies also showed a graded relationship, although the strength of the association was weaker. Studies reporting mean flares or time-to-flare according to SUA showed similar findings.

CONCLUSION

This systematic review confirms that higher SUA levels are associated with increased risk of incident and recurrent gout in a graded manner. Although few prospective cohorts have evaluated incident and recurrent gout according to SUA, the existing evidence underscores the need to treat to SUA targets, as recommended by the American College of Rheumatology and the European League Against Rheumatism.

Racial differences in health-related quality of life and functional ability in patients with gout

OBJECTIVE

To compare the health-related quality of life (HRQOL) and the functional ability by race in patients with gout.

METHODS

In a 9-month prospective cohort multicentre study, patients with gout self-reported race, dichotomized as Caucasian or African American (others excluded). We calculated HRQOL/function scores adjusted for age, study site and college education for Short Form-36 (SF-36; generic HRQOL), Gout Impact Scale (GIS; disease-specific HRQOL) and HAQ-disability index (HAQ-DI; functional ability). Longitudinally adjusted scores were computed using multivariable mixed-effect regression models with a random patient effect and fixed sequential visit effect (3-monthly visits).

RESULTS

Compared with Caucasians (n = 107), African Americans (n = 60) with gout were younger (61.1 vs 67.3 years) and had higher median baseline serum urate (9.0 vs 7.9 mg/dl) (P < 0.01). African Americans with gout had worse HRQOL scores on three SF-36 domains, the mental component summary (MCS) and two of the five GIS scales than Caucasians [mean (se); P ⩽ 0.02 for all]: SF-36 mental health, 39.7 (1.1) vs 45.2 (0.9); SF-36 role emotional, 42.1 (4.2) vs 51.4 (4.2); SF-36 social functioning, 36.0 (1.1) vs 40.0 (0.9) (P = 0.04); SF-36 MCS, 43.2 (3.1) vs 50.0 (3.2); GIS unmet treatment need, 37.6 (1.6) vs 31.5 (1.4); and GIS concern during attacks, 53.3 (3.7) vs 47.4 (3.7). Differences between the respective HAQ-DI total scores were not statistically significant; 0.98 (0.1) vs 0.80 (1.0) (P = 0.11). Racial differences in SF-36 mental health, role emotional and MCS scales exceeded, and for HAQ-DI approached, the minimal clinically important difference thresholds.

CONCLUSIONS

African Americans with gout have significantly worse HRQOL compared with Caucasians. Further research is necessary in the form of studies targeted at African Americans on how best to improve these outcomes.

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

OBJECTIVE

The aim was to evaluate the reliability, validity and responsiveness to change of the Gout Impact Scale (GIS), a disease-specific measure of patient-reported outcomes, in a multicentre longitudinal prospective cohort of gout patients.

METHODS

Subjects completed the GIS, a 24-item instrument with five scales: Concern Overall, Medication Side Effects, Unmet Treatment Need, Well-Being during Attack, and Concern Over Attack. The total GIS score was calculated by averaging the GIS scale scores. HAQ-Disability Index (HAQ-DI), Short Form (SF)-36 physical and mental component summaries (PCS and MCS) and physician and patient gout severity assessments were also completed. Reliability was assessed with Cronbach's α. Baseline GIS scores were compared in subjects with and without gout attacks in the past 3 months using Wilcoxon rank sum tests. Multivariate linear regression was used to evaluate predictors of total GIS. Pearson's correlation coefficients 0.24-0.36 were considered moderate and >0.37 considered large. The effect size for responsiveness to change was interpreted as follows: 0.20-0.49 small, 0.50-0.79 medium and >0.79 large.

RESULTS

In 147 subjects, reliability was acceptable for total GIS (0.93) and all GIS scales (0.82-0.94) except Medication Side Effects and Unmet Treatment Need. Total GIS and all scales except Medication Side Effects discriminated between subjects with and without recent gout attacks (P < 0.05). Total GIS showed moderate-to-large correlations with HAQ-DI, SF-36 PCS and MCS (0.33-0.46). Improvement in total GIS tracked with improved physician and patient severity scores. Worsening physician severity score and recent gout attack predicted worsening total GIS.

CONCLUSION

Total GIS score is reliable, valid and responsive to change in patients with gout, and differentiates between subjects with and without recent gout attacks.

A Systematic Review of the Economic and Humanistic Burden of Gout

BACKGROUND

Gout is a chronic and inflammatory form of arthritis that is often overlooked despite the associated pain caused by acute flares and associated joint damage caused by the development of debilitating tophi. The increasing burden of gout, due to an aging population and the increased prevalence of known risk factors for hyperuricaemia, means that there is a continued need for new and effective urate-lowering treatments. The evaluation of these treatments will require a comprehensive and comparative evidence base describing the economic and humanistic burden of gout, taken from the perspective of patients, the healthcare system, and wider society.

OBJECTIVE

The objective of this study is to review and summarise the current evidence of the disease burden related to chronic gout, assessed in terms of both cost and health-related quality of life (HRQL), and to identify key factors correlated with an increased burden. The overall aim is to support the economic evaluation of new treatments for gout, and to highlight key data gaps that may need further study and exploration.

METHODS

Relevant literature dating from January 2000 to July 2014 was sourced through searches of the MEDLINE database via PubMed and The Cochrane Library. Articles published in English and reporting either the economic burden (cost) or the humanistic burden (HRQL/utility) of gout were identified, and key data were extracted and summarised, with key themes and data gaps identified and discussed.

RESULTS

Of the 323 studies identified, 39 met the inclusion criteria, of which 17 and 26 were relevant to the economic and humanistic burden, respectively. The economic burden of gout varied according to numerous factors, most notably serum urate acid levels and number of flares and tophi, resulting in higher healthcare resource use most often attributed to hospitalisation and inpatient stay. The incremental direct cost of gout has been suggested in the range of US$3165 to US$5515 (2004 and 2005 values, respectively) climbing to US$10,222 to US$21,467 (2008 values) per annum where patients are experiencing regular acute flares and have tophi present. The humanistic burden of gout was largely due to physical disability and pain resulting from chronic clinical manifestations. Short Form 6 dimensions (SF-6D) assessed utility weights are estimated at 0.53 for a patient with severe gout (≥3 flares/year and tophi) compared with 0.73 for an asymptomatic gout patient with serum acid levels <6 mg/dl.

CONCLUSIONS

The evidence confirms that gout has a growing overall prevalence and represents a significant burden in terms of both direct healthcare cost and HRQL outcomes. In light of this, effective urate-lowering treatments are likely to be valued if they can be clearly demonstrated to be both clinically effective and cost effective. Published data to support healthcare decision making in non-US countries with regards to treatments for gout are currently limited, which is a key limitation of the current evidence base. More research is also required to extend our understanding of the impact of gout on indirect costs, and a need also exists to develop a more comprehensive set of comparative HRQL utility assessments.

Experiences of gout-related disability from the patients' perspective: a mixed methods study

Disability is a common problem in patients with gout. Recently, the Health Assessment Questionnaire Disability Index (HAQ-DI) was recommended for assessing patient reported activity limitations in gout. However, few studies have explored experiences and issues of disability from the perspective of gout patients themselves. The objectives of this study were to explore disability issues in patients with gout and to examine the content validity of the HAQ-DI in this patient group. Two studies were performed: a semi-structured interview study with seven male gout patients and a cross-sectional survey study among 34 other patients with gout. In both studies, specific examples of activity limitations were elicited using open-ended methods. The survey study additionally aimed to quantify the relevance of the activities listed in the HAQ-DI. Most patients experienced several gout attacks in the previous year. Limitations were reported to occur during a flare, but patients were generally not limited between attacks. During an attack, patients mainly experienced limitations related to mobility, especially walking and climbing stairs. Patients also mentioned limitations in activities related to domestic life, such as gardening and doing housework. Limitations related to self-care or activities requiring the use of the upper extremities were rarely mentioned. Corresponding HAQ-DI items were skewed towards very low disability scores over the past week. Assessments of gout-related disability should particularly focus on mobility and lower extremity functioning and should consider the intermittent nature of the disease. The HAQ-DI may not adequately meet these requirements, suggesting the need to explore other measures of gout-related disability

Health-related quality of life and treatment satisfaction in patients with gout: results from a cross-sectional study in a managed care setting

BACKGROUND

Patient satisfaction with treatment directly impacts adherence to medication.

OBJECTIVE

The objective was to assess and compare treatment satisfaction with the Treatment Satisfaction Questionnaire for Medication (TSQM), gout-specific health-related quality of life (HRQoL) with the Gout Impact Scale (GIS), and generic HRQoL with the SF-12v2(®) Health Survey (SF-12) in patients with gout in a real-world practice setting.

METHODS

This cross-sectional mail survey included gout patients enrolled in a large commercial health plan in the US. Patients were ≥18 years with self-reported gout diagnosis, who filled ≥1 prescription for febuxostat during April 26, 2012 to July 26, 2012 and were not taking any other urate-lowering therapies. The survey included the TSQM version II (TSQM vII, score 0-100, higher scores indicate better satisfaction), GIS (score 0-100, higher scores indicate worse condition), and SF-12 (physical component summary and mental component summary). Patients were stratified by self-report of currently experiencing a gout attack or not to assess the discriminant ability of the questionnaires.

RESULTS

A total of 257 patients were included in the analysis (mean age, 54.9 years; 87% male). Patients with current gout attack (n=29, 11%) had worse scores than those without gout attack on most instrument scales. Mean differences between current attack and no current attack for the TSQM domains were: -20.6, effectiveness; -10.6, side effects; -12.1, global satisfaction (all P<0.05); and -6.1, convenience (NS). For the GIS, mean differences were: 30.5, gout overall concern; 14.6, gout medication side effects; 22.7, unmet gout treatment needs; 11.5, gout concern during attack (all P<0.05); and 7.9, well-being during attack (NS). Mean difference in SF-12 was -6.6 for physical component summary (P<0.05) and -2.9 for mental component summary (NS). Correlations between several TSQM and GIS scales were moderate.

CONCLUSION

The TSQM and GIS were complementary in evaluating the impact of gout flare on treatment satisfaction and HRQoL. Correlations between the two instruments supported the relationship between treatment satisfaction and HRQoL.

Efficacy of Canakinumab vs. triamcinolone acetonide according to multiple gouty arthritis-related health outcomes measures

AIM

Canakinumab (CAN), a selective, fully human, anti-IL-1β monoclonal antibody, has demonstrated long-term benefits in gouty arthritis (GA) patients, who have contraindications for, or are unresponsive or intolerant of, non-steroidal anti-inflammatory drugs (NSAIDs) or colchicine (two trials:β-RELIEVED [n = 228]; β-RELIEVED II [n = 226]). The trials collected different responses, including patient-reported outcomes (PRO). A composite response end-point (CRE) was used to interpret each patient's overall response to treatment.

METHODS

Data from β-RELIEVED trials were pooled for this retrospective analysis. The CRE representing overall change in GA-related health outcomes, from baseline to 12 weeks, included clinical markers; PROs from the Gout Impact Scale (GIS); and the SF-36 bodily pain scale. Response to each variable (i.e. markedly important difference) was determined a priori. Variable values [1 (responder) or 0 (non-responder)] were summed to create a CRE score for each patient.

RESULTS

For eight of 12 variables measured, the percentage of CAN responders was significantly greater than for TA (p < 0.05). On average, patients receiving CAN met a higher percentage of response criteria (65%) than patients receiving triamcinolone acetonide (TA) (49%), p < 0.001. Mean CRE scores were significantly higher for CAN vs. TA (mean [SD]; 4.7 [2.7] vs. 3.7 [2.4], p < 0.001). Treatment differences remained even after serially removing individual responder variables and domains from the composite end-point, indicating that the differences between CAN and TA were robust.

CONCLUSION

CAN was superior to TA across multiple health-outcome variables comprising clinical markers and PRO over 12 weeks in patients contraindicated, intolerant or unresponsive to NSAIDs and/or colchicine.

Uricosuric medications for chronic gout

BACKGROUND

Uricosuric agents have long been used in the treatment of gout but there is little evidence regarding their benefit and safety in this condition.

OBJECTIVES

To assess the benefits and harms of uricosuric medications in the treatment of chronic gout.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 4, 2013), Ovid MEDLINE and Ovid EMBASE for studies to the 13 May 2013. We also searched the World Health Organization Clinical Trials Registry, ClinicalTrials.gov and the 2011 to 2012 American College of Rheumatology and European League against Rheumatism abstracts. WE considered black box warnings and searched drug safety databases to identify and describe rare adverse events.

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) or quasi-randomised controlled trials (controlled clinical trials (CCTs)) that compared uricosuric medications (benzbromarone, probenecid or sulphinpyrazone) alone or in combination with another therapy (placebo or other active uric acid-lowering medication, or non-pharmacological treatment) in adults with chronic gout for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies for inclusion, extracted data and performed a risk of bias assessment. Main outcomes were frequency of acute gout attacks, serum urate normalisation, study participant withdrawal due to adverse events, total adverse events, pain reduction, function and tophus regression.

MAIN RESULTS

The search identified four RCTs and one CCT that evaluated the benefit and safety of uricosurics for gout. One study (65 participants) compared benzbromarone with allopurinol for a duration of four months; one compared benzbromarone with allopurinol (36 participants) for a duration of nine to 24 months; one study (62 participants) compared benzbromarone with probenecid for two months and one study (74 participants) compared benzbromarone with probenecid. One study (37 participants) compared allopurinol with probenecid. No study was completely free from bias.Low-quality evidence from one study (55 participants) comparing benzbromarone with allopurinol indicated uncertain effects in terms of frequency of acute gout attacks (4% with benzbromarone versus 0% with allopurinol; risk ratio (RR) 3.58, 95% confidence interval (CI) 0.15 to 84.13), while moderate-quality evidence from two studies (101 participants; treated for four to nine months) indicated similar proportions of participants achieving serum urate normalisation (73.9% with benzbromarone versus 60% with allopurinol; pooled RR 1.27, 95% CI 0.90 to 1.79). Low-quality evidence indicated uncertain differences in withdrawals due to adverse events (7.1% with benzbromarone versus 6.1% with allopurinol; pooled RR 1.25, 95% CI 0.28 to 5.62), and total adverse events (20% with benzbromarone versus 6.7% with allopurinol; RR 3.00, 95% CI 0.64 to 14.16). The study did not measure pain reduction, function and tophus regression.When comparing benzbromarone with probenecid, there was moderate-quality evidence based on one study (62 participants) that participants taking benzbromarone were more likely to achieve serum urate normalisation after two months (81.5% with benzbromarone versus 57.1% with probenecid; RR 1.43, 95% CI 1.02 to 2.00). This indicated that when compared with probenecid, five participants needed to be treated with benzbromarone in order to have one additional person achieve serum urate normalisation (number needed to treat for an additional beneficial outcome (NNTB) 5). However, the second study reported no difference in the absolute decrease in serum urate between these groups after 12 weeks. Low-quality evidence from two studies (129 participants) indicated uncertain differences between treatments in the frequency of acute gout attacks (6.3% with benzbromarone versus 10.6% with probenecid; pooled RR 0.73, 95% CI 0.09 to 5.83); fewer withdrawals due to adverse events with benzbromarone (2% with benzbromarone versus 17% with probenecid; pooled RR 0.15, 95% CI 0.03 to 0.79, NNTB 7) and fewer total adverse events (21% with benzbromarone versus 47% with probenecid; pooled RR 0.43, 95% CI 0.25 to 0.74; NNTB 4). The studies did not measure pain reduction, function and tophus regression.Low-quality evidence based on one small CCT (37 participants) indicated uncertainty around the difference in the incidence of acute gout attacks between probenecid and allopurinol after 18 to 20 months' treatment (53% with probenecid versus 55% with allopurinol; RR 0.96, 95% CI 0.53 to 1.75). The study did not measure or report the proportion achieving serum urate normalisation, pain reduction, function, tophus regression, withdrawal due to adverse events and total adverse events.

AUTHORS' CONCLUSIONS

There was moderate-quality evidence that there is probably no important difference between benzbromarone and allopurinol at achieving serum urate normalisation, but that benzbromarone is probably more successful than probenecid at achieving serum urate normalisation in people with gout. There is some uncertainty around the effect estimates, based on low-quality evidence from only one or two trials, on the number of acute gout attacks, the number of withdrawals due to adverse events or the total number of participants experiencing adverse events when comparing benzbromarone with allopurinol. However, when compared with probenecid, benzbromarone resulted in fewer withdrawals due to adverse events and fewer participants experiencing adverse events. Low-quality evidence from one small study indicated uncertain effects in the incidence of acute gout attacks when comparing probenecid with allopurinol therapy. We downgraded the evidence because of a possible risk of performance and other biases and imprecision.

Allopurinol for chronic gout

BACKGROUND

Allopurinol, a xanthine oxidase inhibitor, is considered one of the most effective urate-lowering drugs and is frequently used in the treatment of chronic gout.

OBJECTIVES

To assess the efficacy and safety of allopurinol compared with placebo and other urate-lowering therapies for treating chronic gout.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE on 14 January 2014. We also handsearched the 2011 to 2012 American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) abstracts, trial registers and regulatory agency drug safety databases.

SELECTION CRITERIA

All randomised controlled trials (RCTs) or quasi-randomised controlled clinical trials (CCTs) that compared allopurinol with a placebo or an active therapy in adults with chronic gout.

DATA COLLECTION AND ANALYSIS

We extracted and analysed data using standard methods for Cochrane reviews. The major outcomes of interest were frequency of acute gout attacks, serum urate normalisation, pain, function, tophus regression, study participant withdrawal due to adverse events (AE) and serious adverse events (SAE). We assessed the quality of the body of evidence for these outcomes using the GRADE approach.

MAIN RESULTS

We included 11 trials (4531 participants) that compared allopurinol (various doses) with placebo (two trials); febuxostat (four trials); benzbromarone (two trials); colchicine (one trial); probenecid (one trial); continuous versus intermittent allopurinol (one trial) and different doses of allopurinol (one trial). Only one trial was at low risk of bias in all domains. We deemed allopurinol versus placebo the main comparison, and allopurinol versus febuxostat and versus benzbromarone as the most clinically relevant active comparisons and restricted reporting to these comparisons here.Moderate-quality evidence from one trial (57 participants) indicated allopurinol 300 mg daily probably does not reduce the rate of gout attacks (2/26 with allopurinol versus 3/25 with placebo; risk ratio (RR) 0.64, 95% confidence interval (CI) 0.12 to 3.52) but increases the proportion of participants achieving a target serum urate over 30 days (25/26 with allopurinol versus 0/25 with placebo, RR 49.11, 95% CI 3.15 to 765.58; number needed to treat for an additional beneficial outcome (NNTB) 1). In two studies (453 participants), there was no significant increase in withdrawals due to AE (6% with allopurinol versus 4% with placebo, RR 1.36, 95% CI 0.61 to 3.08) or SAE (2% with allopurinol versus 1% with placebo, RR 1.93, 95% CI 0.48 to 7.80). One trial reported no difference in pain reduction or tophus regression, but did not report outcome data or measures of variance sufficiently and we could not calculate the differences between groups. Neither trial reported function.Low-quality evidence from three trials (1136 participants) indicated there may be no difference in the incidence of acute gout attacks with allopurinol up to 300 mg daily versus febuxostat 80 mg daily over eight to 24 weeks (21% with allopurinol versus 23% with febuxostat, RR 0.89, 95% CI 0.71 to 1.1); however more participants may achieve target serum urate level (four trials; 2618 participants) with febuxostat 80 mg daily versus allopurinol 300 mg daily (38% with allopurinol versus 70% with febuxostat, RR 0.56, 95% CI 0.48 to 0.65, NNTB with febuxostat 4). Two trials reported no difference in tophus regression between allopurinol and febuxostat over a 28- to 52-week period; but as the trialists did not provide variance, we could not calculate the mean difference between groups. The trials did not report pain reduction or function. Moderate-quality evidence from pooled data from three trials (2555 participants) comparing allopurinol up to 300 mg daily versus febuxostat 80 mg daily indicated no difference in the number of withdrawals due to AE (7% with allopurinol versus 8% with febuxostat, RR 0.89, 95% CI 0.62 to 1.26) or SAE (4% with allopurinol versus 4% with febuxostat, RR 1.13, 95% CI 0.71 to 1.82) over a 24- to 52-week period.Low-quality evidence from one trial (65 participants) indicated there may be no difference in the incidence of acute gout attacks with allopurinol up to 600 mg daily compared with benzbromarone up to 200 mg daily over a four-month period (0/30 with allopurinol versus 1/25 with benzbromarone, RR 0.28, 95% CI 0.01 to 6.58). Based on the pooled results of two trials (102 participants), there was moderate-quality evidence of no probable difference in the proportion of participants achieving a target serum urate level with allopurinol versus benzbromarone (58% with allopurinol versus 74% with benzbromarone, RR 0.79, 95% CI 0.56 to 1.11). Low-quality evidence from two studies indicated there may be no difference in the number of participants who withdrew due to AE with allopurinol versus benzbromarone over a four- to nine-month period (6% with allopurinol versus 7% with benzbromarone, pooled RR 0.80, 95% CI 0.18 to 3.58). There were no SAEs. They did not report tophi regression, pain and function.All other comparisons were supported by small, single studies only, limiting conclusions.

AUTHORS' CONCLUSIONS

Our review found low- to moderate-quality evidence indicating similar effects on withdrawals due to AEs and SAEs and incidence of acute gout attacks when allopurinol (100 to 600 mg daily) was compared with placebo, benzbromarone (100 to 200 mg daily) or febuxostat (80 mg daily). There was moderate-quality evidence of little or no difference in the proportion of participants achieving target serum urate when allopurinol was compared with benzbromarone. However, allopurinol seemed more successful than placebo and may be less successful than febuxostat (80 mg daily) in achieving a target serum urate level (6 mg/dL or less; 0.36 mmol/L or less) based on moderate- to low-quality evidence. Single studies reported no difference in pain reduction when allopurinol (300 mg daily) was compared with placebo over 10 days, and no difference in tophus regression when allopurinol (200 to 300 mg daily) was compared with febuxostat (80 mg daily). None of the trials reported on function, health-related quality of life or participant global assessment of treatment success, where further research would be useful.

The Gout Assessment Questionnaire 2.0: cross-cultural translation into Dutch, aspects of validity and linking to the International Classification of Functioning, Disability and Health

OBJECTIVES

The Gout Assessment Questionnaire 2.0 (GAQ2.0) is a disease-specific patient-reported outcome measure for gout that distinguishes five different subscales and comprises overall 31 questions. The aims of this study were to translate the GAQ2.0 into Dutch and to test clinimetric properties.

METHODS

Recommendations for translation and cross-cultural adaptation were followed and no cultural adaptations were needed. The resulting Dutch GAQ2.0 was administered to patients registered at the rheumatology outpatient clinic diagnosed with gout. Internal consistency was tested using Cronbach's α, reliability using intraclass correlation coefficient (ICC), content validity by linkage to the International Classification of Functioning, Disability and Health (ICF) and construct validity by correlating the subscales of the GAQ2.0 with the HAQ disability index (HAQ-DI) and 36-item Short Form Health Survey (SF-36).

RESULTS

A total of 126 patients [106 (84%) male, mean age 66.6 years (s.d. 10.4), mean disease duration 11.2 years (s.d. 10.6)] completed a number of questionnaires, including the GAQ2.0, HAQ-DI and SF-36, and underwent a clinical examination. Internal consistency was sufficient (Cronbach's α = 0.83-0.94), except for the subscale gout medication side effects (Cronbach's α = 0.51). Test-retest reliability was good (ICCs 0.73-0.86) for all subscales, but moderate for the subscale unmet gout treatment need (ICC 0.56). Gout impact (GI) subscale scores showed only weak to moderate correlations with HAQ-DI and SF-36, but stronger emphasis on the emotional consequences of gout. Also, it correlated better with gout-specific outcomes such as the number of gout flares and pain.

CONCLUSION

The Dutch GAQ2.0 shows sufficient evidence of validity to assess disease-specific functioning and health in patients with gout and seems to capture different aspects than those represented in the HAQ and SF-36.

Health-related quality of life in gout: a systematic review

Objectives. To identify the instruments that have been used to measure health-related quality of life (HRQOL) in gout and assess their clinimetric properties, determine the distribution of HRQOL in gout and identify factors associated with poor HRQOL.

Methods. Medline, CINAHL, EMBASE and PsycINFO were searched from inception to October 2012. Search terms pertained to gout, health or functional status, clinimetric properties and HRQOL. Study data extraction and quality assessment were performed by two independent reviewers.

Results. From 474 identified studies, 22 met the inclusion criteria. Health Assessment Questionnaire Disability Index (HAQ-DI) and Short Form 36 (SF-36) were most frequently used and highest rated due to robust construct and concurrent validity, despite high floor and ceiling effects. The Gout Impact Scale had good content validity. Gout had a greater impact on physical HRQOL compared to other domains. Both gout-specific features (attack frequency and intensity, intercritical pain and number of joints involved) and comorbid disease were associated with poor HRQOL. Evidence for objective features such as tophi and serum uric acid was less robust. Limitations of existing studies include cross-sectional design, recruitment from specialist clinic settings and frequent use of generic instruments.

Conclusion. Most studies have used the generic HAQ-DI and SF-36. Gout-specific characteristics and comorbidities contribute to poor HRQOL. There is a need for a cohort study in primary care (where most patients with gout are treated) to determine which factors predict changes in HRQOL over time. This will enable those at risk of deterioration to be identified and better targeted for treatment.

Lifestyle interventions for chronic gout

BACKGROUND

Although lifestyle interventions are commonly recommended in the management of patients with chronic gout, the evidence from trial data for their benefits and safety has not been previously examined in a systematic review.

OBJECTIVES

The objective of this systematic review was to evaluate the benefits and safety of lifestyle interventions for the treatment of people with chronic gout.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE for studies on 5 April 2013. We also searched the 2010 to 2011 American College of Rheumatology (ACR) and European League against Rheumatism (EULAR) abstracts and performed a handsearch of the reference lists of included articles.

SELECTION CRITERIA

Studies were included if they were randomised or quasi-randomised controlled trials (RCTs or CCTs) which compared lifestyle interventions to another therapy (active or placebo) in patients with chronic gout. Outcomes of interest were changes in gout attack frequency, joint pain, serum urate levels, tophus size, function, quality of life and adverse effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied methods recommended by The Cochrane Collaboration for the selection, appraisal, data collection and synthesis of studies. We assessed the quality of the body of evidence for each outcome using the GRADE approach.

MAIN RESULTS

Only one study (120 participants), at moderate risk of bias, was included in the review. Patients were randomised to one of three interventions: either skim milk powder (SMP) enriched with glycomacropeptide (GMP) and G600, non-enriched SMP or lactose powder, over a three-month period. The frequency of acute gout attacks, measured as the number of flares per month, decreased in all three groups over the three-month study period. Low quality evidence indicated that there was no difference between the SMP/GMP/G600 group and combined control groups (SMP and lactose powder) at three months (mean difference (MD) -0.21, 95% confidence interval (CI) -0.76 to 0.34). There were no significant between-group differences in terms of withdrawals due to adverse effects (risk ratio (RR) 1.27, 95% CI 0.53 to 3.03), and serious adverse events resulting in hospitalisation (2/40 SMP/GMP/G600 group versus 3/80 controls; RR 1.33, 95% CI 0.23 to 7.66). Gastrointestinal adverse effects were the most commonly reported. Pain from self reported gout flares, measured on a 10-point Likert scale, improved more in the SMP/GMP/G600 group compared to controls (MD -1.03, 95% CI -1.96 to -0.10), an absolute difference of 10% (absolute risk difference -0.10, 95% CI -0.20 to -0.01). This is unlikely to be of clinical significance. Physical function, tophus regression and serum urate normalisation were not reported in this study.

AUTHORS' CONCLUSIONS

While there is good evidence from observational studies of an association between various lifestyle risk factors and gout development, there is a paucity of high-quality evidence from randomised controlled trials to either support or refute the use of lifestyle modifications for improving outcomes in people with chronic gout.

Disability due to gouty arthritis

PURPOSE OF REVIEW

Disability, or activity limitation, is a common problem in patients with gout. This study explores recent studies examining the nature and extent of disability in gout and addresses the merits and limitations of current self-reported measures of disability.

RECENT FINDINGS

Gout has a significant impact on patients' ability to perform normal self-care activities, recreational and social activities, and work. Comparative studies indicate that gout patients' physical functioning is strongly reduced and comparable to those with other severe rheumatic conditions. Moreover, gout has been shown to result in substantial work absence and reduced productivity. However, few studies have thoroughly examined the concept of disability in gout. Additionally, assessment of disability due to gout still seems particularly challenging and it is unclear whether current measurement instruments are sufficiently valid and accurate.

SUMMARY

Gout-related disability is an underestimated and understudied problem. More qualitative and quantitative studies are needed that examine the concept of disability in gout and its impact on patients' lives, both during and between disease flares. Moreover, future studies should try to identify gout-specific disability issues and examine the relevance and comprehensiveness of existing measures to further improve the assessment of disability in gout.

Efficacy of anakinra for refractory acute calcium pyrophosphate crystal arthritis

Acute synovitis induced by deposition of calcium pyrophosphate (CPP) and monosodium urate crystals involves interleukin-1β production and activation. The efficacy of blocking interleukin-1β activity (with an interleukin-1 receptor antagonist [anakinra] or interleukin-1β antibody) is well documented for gout attacks but has only been reported in two single-case reports of CPP crystal-induced acute arthritis. Here we report on five cases (four males, mean age 71±27) of CPP crystal-induced inflammatory arthritis refractory and/or intolerant to usual drug therapy and efficiently treated with anakinra. Diagnosis of CPP crystal-induced arthritis was confirmed by identification of crystals in synovial fluid. CPP crystal-induced oligo-arthritis (n=4) and polyarthritis (n=1) were refractory to conventional treatments, including non-steroidal anti-inflammatory drugs, colchicine and steroids (systemic administration or intra-articular injection). After latent infection was ruled out, anakinra, 100mg/day, was administered subcutaneously for 3 days. Four patients showed rapid clinical and biological responses at a mean of 3 days after treatment. Anakinra provided good joint pain relief (baseline 0-100mm visual analog scale score 60±17mm, outcome 10±10mm) and decreased serum C-reactive protein level (58±43 to 5±2mg/L). Anakinra was well tolerated. One injection-site skin reaction was observed but no infection. Anakinra was effective and safe in this small series of patients with refractory arthritis due to acute CPP crystal deposition.

Patient-reported outcomes in chronic gout: a report from OMERACT 10

OBJECTIVE

To summarize the endorsement of measures of patient-reported outcome (PRO) domains in chronic gout at the 2010 Outcome Measures in Rheumatology Meeting (OMERACT 10).

METHODS

During the OMERACT 10 gout workshop, validation data were presented for key PRO domains including pain [pain by visual analog scale (VAS)], patient global (patient global VAS), activity limitation [Health Assessment Questionnaire-Disability Index (HAQ-DI)], and a disease-specific measure, the Gout Assessment Questionnaire version 2.0 (GAQ v2.0). Data were presented on all 3 aspects of the OMERACT filters of truth, discrimination, and feasibility. One PRO, health-related quality of life measurement with the Medical Outcomes Study Short-form 36 (SF-36), was previously endorsed at OMERACT 9.

RESULTS

One measure for each of the 3 PRO of pain, patient global, and activity limitation was endorsed by > 70% of the OMERACT delegates to have appropriate validation data. Specifically, pain measurement by VAS was endorsed by 85%, patient global assessment by VAS by 73%, and activity limitation by HAQ-DI by 71%. GAQ v2.0 received 30% vote and was not endorsed due to several concerns including low internal consistency and lack of familiarity with the measure. More validation studies are needed for this measure.

CONCLUSION

With the endorsement of one measure each for pain, patient global, SF-36, and activity limitation, all 4 PRO for chronic gout have been endorsed. Future validation studies are needed for the disease-specific measure, GAQ v2.0. Validation for PRO for acute gout will be the focus of the next validation exercise for the OMERACT gout group.