Identification of patients with gout: elaboration of a questionnaire for epidemiological studies

The gout epidemic in French Polynesia: a modelling study of data from the Ma'i u'u epidemiological survey

BACKGROUND

Gout is the most common cause of inflammatory arthritis worldwide, particularly in Pacific regions. We aimed to establish the prevalence of gout and hyperuricaemia in French Polynesia, their associations with dietary habits, their comorbidities, the prevalence of the HLA-B*58:01 allele, and current management of the disease.

METHODS

The Ma'i u'u survey was epidemiological, prospective, cross-sectional, and gout-focused and included a random sample of adults from the general adult population of French Polynesia. It was conducted and data were collected between April 13 and Aug 16, 2021. Participants were randomly selected to represent the general adult population of French Polynesia on the basis of housing data collected during the 2017 territorial census. Each selected household was visited by a research nurse from the Ma'i u'u survey who collected data via guided, 1-h interviews with participants. In each household, the participant was the individual older than 18 years with the closest upcoming birthday. To estimate the frequency of HLA-B*58:01, we estimated HLA-B haplotypes on individuals who had whole-genome sequencing to approximately 5× average coverage (mid-pass sequencing). A subset of individuals who self-reported Polynesian ancestry and not European, Chinese, or other ancestry were used to estimate Polynesian-ancestry specific allele frequencies. Bivariate associations were reported for weighted participants; effect sizes were estimated through the odds ratio (OR) of the association calculated on the basis of a logistic model fitted with weighted observations.

FINDINGS

Among the random sample of 2000 households, 896 participants were included, 140 individuals declined, and 964 households could not be contacted. 22 participants could not be weighted due to missing data, so the final weighted analysis included 874 participants (449 [51·4%] were female and 425 [48·6%] were male) representing the 196 630 adults living in French Polynesia. The estimated prevalence of gout was 14·5% (95% CI 9·9-19·2), representing 28 561 French Polynesian adults, that is 25·5% (18·2-32·8) of male individuals and 3·5% (1·0-6·0) of female individuals. The prevalence of hyperuricaemia was estimated at 71·6% (66·7-76·6), representing 128 687 French Polynesian adults. In multivariable analysis, age (OR 1·5, 95% CI 1·2-1·8 per year), male sex (10·3, 1·8-60·7), serum urate (1·6, 1·3-2·0 per 1 mg/dL), uraturia (0·8, 0·8-0·8 per 100 mg/L), type 2 diabetes (2·1, 1·4-3·1), BMI more than 30 kg/m2 (1·1, 1·0-1·2 per unit), and percentage of visceral fat (1·7, 1·1-2·7 per 1% increase) were associated with gout. There were seven heterozygous HLA-B*58:01 carriers in the full cohort of 833 individuals (seven [0·4%] of 1666 total alleles) and two heterozygous carriers in a subset of 696 individuals of Polynesian ancestry (two [0·1%]).

INTERPRETATION

French Polynesia has an estimated high prevalence of gout and hyperuricaemia, with gout affecting almost 15% of adults. Territorial measures that focus on increasing access to effective urate-lowering therapies are warranted to control this major public health problem.

FUNDING

Variant Bio, the French Polynesian Health Administration, Lille Catholic University Hospitals, French Society of Rheumatology, and Novartis.

Epidemiology of gout and hyperuricemia in New Caledonia

OBJECTIVES

New Caledonia is a Pacific island of 270,000 inhabitants with mixed ethnicities, including Polynesians (10.2%), people from European ancestry (27.2%), and Melanesians (39.1%),. This study aimed at determining the prevalence of gout and hyperuricemia in the general population and the various ethnicities of New Caledonia.

METHODS

A 3-degree random sample of the population aged 18 to 60 years was adjusted according to the 2014 New Caledonia census. Face-to-face planned interviews and physical measurements were performed by trained nurses. All consenting participants underwent capillary measurement of creatinine; all consenting men and only women older than 40 years underwent point-of-care uricemia testing. Gout was defined by a validated algorithm. Two definitions of hyperuricemia were used: capillary level equivalent to plasma uric acid level>360μmol/l (6mg/dl) and>420μmol/l (7mg/dl) and/or urate-lowering drug treatment for both thresholds.

RESULTS

We included 1144 participants (adjusted mean age 37.7±12.0 years; adjusted sex ratio 50.4% men). The adjusted prevalence of gout was 3.3% (95% confidence interval 2.2-4.9). Prevalence was 6.7% (2.5-16.8), 4.1% (1.8-8.9), and 2.6% (1.4-4.7) for Polynesians, Europeans and Melanesians, respectively, and 1.9% (0.5-6.6) for other ethnicities. Prevalence of hyperuricemia, determined in 658 participants, was 67.0% (61.9-71.6) and 37.0% (32.3-42.0) for the 360- and 420-μmol/l thresholds, respectively, and was significantly greater for Polynesians and Melanesians than Europeans for both thresholds.

CONCLUSIONS

The prevalence of gout and hyperuricemia in New Caledonia was high, including in patients of European descent.

Dual-energy CT in the differentiation of crystal depositions of the wrist: does it have added value?

OBJECTIVES

To evaluate the ability of dual-energy computed tomography (DECT) to improve diagnostic discrimination between gout and other crystal arthropathies such as calcium pyrophosphate deposition disease (CPPD) of the wrist in a clinical patient population.

MATERIALS AND METHODS

This retrospective case-control study included 29 patients with either gout (case group; n = 9) or CPPD (control group; n = 20) who underwent DECT of the wrist for clinically suspected crystal arthropathy. Color-coded urate and enhanced calcium as well as virtual 120 kVe blended images were reconstructed from the DECT datasets. Two independent and blinded readers evaluated each reconstructed dataset for the presence of depositions in 17 predefined regions. Additionally, a global diagnosis was made first for 120 kVe images only, based solely on morphologic criteria, and subsequently for all reconstructed images.

RESULTS

Sensitivity for the global diagnosis of gout was 1.0 (95% CI 0.63-1) for both DECT and 120 kVe images with specificities of 0.70 (95% CI 0.46-0.87) for DECT and 0.80 (95% CI 0.56-0.93) for 120 kVe images. Color-coded DECT images did not detect more depositions than monochrome standard CT images.

CONCLUSION

Discrimination of crystal arthropathies of the wrist is limited using DECT and primarily relying on color-coded images. Evaluation of morphologic criteria on standard CT images is essential for accurate diagnosis.

Gout: state of the art after a decade of developments

This review article summarizes the relevant English literature on gout from 2010 through April 2017. It emphasizes that the current epidemiology of gout indicates a rising prevalence worldwide, not only in Western countries but also in Southeast Asia, in close relationship with the obesity and metabolic syndrome epidemics. New pathogenic mechanisms of chronic hyperuricaemia focus on the gut (microbiota, ABCG2 expression) after the kidney. Cardiovascular and renal comorbidities are the key points to consider in terms of management. New imaging tools are available, including US with key features and dual-energy CT rendering it able to reveal deposits of urate crystals. These deposits are now included in new diagnostic and classification criteria. Overall, half of the patients with gout are readily treated with allopurinol, the recommended xanthine oxidase inhibitor (XOI), with prophylaxis for flares with low-dose daily colchicine. The main management issues are related to patient adherence, because gout patients have the lowest rate of medication possession ratio at 1 year, but they also include clinical inertia by physicians, meaning XOI dosage is not titrated according to regular serum uric acid level measurements for targeting serum uric acid levels for uncomplicated (6.0 mg/dl) and complicated gout, or the British Society for Rheumatology recommended target (5.0 mg/dl). Difficult-to-treat gout encompasses polyarticular flares, and mostly patients with comorbidities, renal or heart failure, leading to contraindications or side effects of standard-of-care drugs (colchicine, NSAIDs, oral steroids) for flares; and tophaceous and/or destructive arthropathies, leading to switching between XOIs (febuxostat) or to combining XOI and uricosurics.

Risk factors for the formation of double-contour sign and tophi in gout

BACKGROUND

This study aimed to confirm the diagnostic accuracy of ultrasound (US) on gout and explore the potential risk factors for double-contour sign and tophi formation in gout patients.

METHODS

The US analyses were performed on all knee, ankle, and first metatarsophalangeal (MTP 1) joints to reveal the type and location of lesions. While a questionnaire and blood biochemical index were used to explore the potential risk factors for double-contour sign and tophi in gout, the SPSS17.0 software was used for statistical analysis in the present study.

RESULTS

Totally, 117 gout patients with 702 joints (38 lesions in knee joint, 93 lesions in ankle joint, and 112 lesions in MTP 1 joint) were enrolled in current analyses. Double-contour sign and joint effusion were the two most outstanding lesion manifestations in knee joints and ankle joints. Tophi and double-contour sign were the two most outstanding lesion manifestations in TMP 1 joints. Moreover, factors including uric acid (UA) level and the highest blood UA were potential risk factors of the double-contour sign, while age and history of US were potential risk factors for tophi.

CONCLUSION

US was effective on the joints of gout patients. There was US sensitivity for tophi and double-contour sign in MTP 1 joints. The double-contour sign was a potential specific manifestation in knee joints and ankle joints. Furthermore, UA and highest blood UA level were potential risk factors for double-contour sign, while age and US history were potential risk factors for tophi.

2018 updated European League Against Rheumatism evidence-based recommendations for the diagnosis of gout

Although gout is the most common inflammatory arthritis, it is still frequently misdiagnosed. New data on imaging and clinical diagnosis have become available since the first EULAR recommendations for the diagnosis of gout in 2006. This prompted a systematic review and update of the 2006 recommendations. A systematic review of the literature concerning all aspects of gout diagnosis was performed. Recommendations were formulated using a Delphi consensus approach. Eight key recommendations were generated. A search for crystals in synovial fluid or tophus aspirates is recommended in every person with suspected gout, because demonstration of monosodium urate (MSU) crystals allows a definite diagnosis of gout. There was consensus that a number of suggestive clinical features support a clinical diagnosis of gout. These are monoarticular involvement of a foot or ankle joint (especially the first metatarsophalangeal joint); previous episodes of similar acute arthritis; rapid onset of severe pain and swelling; erythema; male gender and associated cardiovascular diseases and hyperuricaemia. When crystal identification is not possible, it is recommended that any atypical presentation should be investigated by imaging, in particular with ultrasound to seek features suggestive of MSU crystal deposition (double contour sign and tophi). There was consensus that a diagnosis of gout should not be based on the presence of hyperuricaemia alone. There was also a strong recommendation that all people with gout should be systematically assessed for presence of associated comorbidities and risk factors for cardiovascular disease, as well as for risk factors for chronic hyperuricaemia. Eight updated, evidence-based, expert consensus recommendations for the diagnosis of gout are proposed.

A meta-analysis of the association between gout, serum uric acid level, and obstructive sleep apnea

Previous epidemiological investigations have evaluated the association between gout, serum uric acid levels, and obstructive sleep apnea syndrome (OSAS), but with inconsistent results. We conducted this meta-analysis aiming at providing clear evidence about whether OSAS patients have higher serum uric acid levels and more susceptible to gout. Relevant studies were identified via electronic databases from inception to December 17, 2018. Study selection was conducted according to predesigned eligibility criteria, and two authors independently extracted data from included studies. The hazard ratio (HR) and weighted mean difference (WMD) and their corresponding 95% confidence interval (CI) were derived using random-effects models. We conducted meta-, heterogeneity, publication bias, sensitivity, and subgroup analyses. Eighteen studies, involving a total of 157,607 individuals (32,395 with OSAS, 125,212 without OSAS) and 12,262 gout cases, were included. Results show that serum uric acid levels are elevated in patients with OSAS (WMD = 52.25, 95% CI 36.16-64.33); OSAS did not reach statistical significance as a predictor of gout (but there was a trend, HR = 1.25, 95% CI 0.91-1.70) and that the association between OSAS and serum uric acid was quite robust. OSAS may be a potential risk factor for hyperuricemia and the development of gout and thus, effective OSAS therapy may present as a valuable preventive measure against gout. Still, it is vital to undertake clinical studies with better designing to corroborate these associations and shed new light on it.

Survey Definitions of Gout for Epidemiologic Studies: Comparison With Crystal Identification as the Gold Standard

OBJECTIVE

To identify the best-performing survey definition of gout from items commonly available in epidemiologic studies.

METHODS

Survey definitions of gout were identified from 34 epidemiologic studies contributing to the Global Urate Genetics Consortium (GUGC) genome-wide association study. Data from the Study for Updated Gout Classification Criteria (SUGAR) were randomly divided into development and test data sets. A data-driven case definition was formed using logistic regression in the development data set. This definition, along with definitions used in GUGC studies and the 2015 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) gout classification criteria were applied to the test data set, using monosodium urate crystal identification as the gold standard.

RESULTS

For all tested GUGC definitions, the simple definition of "self-report of gout or urate-lowering therapy use" had the best test performance characteristics (sensitivity 82%, specificity 72%). The simple definition had similar performance to a SUGAR data-driven case definition with 5 weighted items: self-report, self-report of doctor diagnosis, colchicine use, urate-lowering therapy use, and hyperuricemia (sensitivity 87%, specificity 70%). Both of these definitions performed better than the 1977 American Rheumatism Association survey criteria (sensitivity 82%, specificity 67%). Of all tested definitions, the 2015 ACR/EULAR criteria had the best performance (sensitivity 92%, specificity 89%).

CONCLUSION

A simple definition of "self-report of gout or urate-lowering therapy use" has the best test performance characteristics of existing definitions that use routinely available data. A more complex combination of features is more sensitive, but still lacks good specificity. If a more accurate case definition is required for a particular study, the 2015 ACR/EULAR gout classification criteria should be considered.

Incidence and prevalence of gout in Western Sweden

BACKGROUND

The aim of the present study was to describe prevalence and trends in the incidence of gout and patterns of urate-lowering treatment (ULT) in the Western Swedish Health Care Region (WSHCR) from 2002 to 2012.

METHODS

We used regional and national healthcare registers to estimate the prevalence and incidence of gout in 2012, and trends in incidence for each calendar year from 2005 to 2012. We also investigated the pattern of ULT for gout using the Swedish Prescribed Drug Register.

RESULTS

In 2012, in the population aged 20 years and above, the prevalence of gout was 1.8 % (95 % confidence interval (CI) 1.77 to 1.82) and the incidence was 190 cases (95 % CI 180 to 200) per 100,000 person-years. Applying more strict definitions for a gout case rendered a prevalence of 1.36 % (95 % CI 1.34 to 1.38) and 0.5 (95 % CI 0.49 to 0.51) per 100,000 person-years, respectively. The incidence of gout increased steadily and significantly from 2005 to 2012, with an almost 50 % increase in the total population. There was no significant difference in the prevalence of gout in rural compared to urban areas. ULT was dispensed to only 42 % of patients with gout in 2012 who had ever been diagnosed with gout during the preceding 10-year period.

CONCLUSIONS

Gout is the most common arthritic disease in WSHCR, Sweden, and has increased substantially over the last decade, with only a minority of prevalent cases in 2012 receiving ULT.

Prevalence of Gout in the Adult Population of France

OBJECTIVE

To estimate adult gout prevalence in France.

METHODS

We used a previously established phone questionnaire that allowed for classifying patients as gouty or nongouty by 2 logistic regression models and 1 classification and regression tree (CART) model, the sensitivity and specificity of which were all more than 80%. The full questionnaire was administered by phone to subjects who acknowledged present or past nontraumatic acute pain in a peripheral joint, the others being classified as nongouty. A random sample of adults residing in France was derived from the national telephone directory (home and mobile) by the quota method and further redressed to match the French population. The target size for the interview survey conducted in March and June 2013 was 10,000 participants.

RESULTS

We interviewed 10,026 participants. All 3 models (2 logistic regression models and a CART model) converged to an estimated gout prevalence of 0.9%. This prevalence was lower than that estimated by self-reporting only (3.7% [95% confidence interval 3.3-4.1]). The prevalence was higher for men than women and increased with age but did not differ by area of France.

CONCLUSION

Gout prevalence in the adult population of France in 2013 was estimated at 0.9%. Studies using self-reporting only might overestimate the prevalence.

Alcohol-related diseases and alcohol dependence syndrome is associated with increased gout risk: A nationwide population-based cohort study

OBJECTIVE

Alcohol intake is strongly associated with hyperuricemia, which may cause gout. This study evaluated the risk of gout in patients with alcohol-related diseases and alcohol dependence syndrome.

METHODS

We used the Taiwan National Health Insurance Research Database (NHIRD) to conduct a nationwide population-based cohort study to assess the risk of gout and gout incidence in patients with alcohol-related diseases and alcohol dependence syndrome (as defined by the International Classification of Diseases, Ninth Revision). In the NHIRD records from 1998 to 2008, we identified 11,675 cases of alcohol-related diseases. The control group comprised 23,350 cases without alcohol-related diseases propensity score-matched (1 case: 2 controls) for age, age group, and sex.

RESULTS

The results revealed that alcohol-related diseases were significantly associated with gout risk (adjusted hazard ratio 1.88; P<0.0001). Of the alcohol-related disease cases, 34.1% of the patients had alcohol dependence syndrome (males 34.8%; females 32.4%), and alcohol dependence was independently associated with gout occurrence (relative risk [RR] 2.01; P<0.0001). Severe alcohol-dependent patients (who were also the heavy benzodiazepines users), were associated with an increased risk of gout (RR 1.71 to 4.21, P≤0.0182).

CONCLUSION

Physicians should be aware of the association between alcohol dependence syndrome and gout occurrence, and alcohol use assessment and measures to prevent alcohol dependence should be implemented in the integrative care for patients with gout.

Sleep Apnea and the Risk of Incident Gout: A Population-Based, Body Mass Index-Matched Cohort Study

OBJECTIVE

Sleep apnea is associated with hyperuricemia owing to hypoxia-induced nucleotide turnover. We undertook this study to assess the relationship between incident sleep apnea and the risk of incident gout.

METHODS

Using data from The Health Improvement Network in the UK, we identified individuals with a first-ever physician diagnosis of sleep apnea. For each patient with sleep apnea, up to 5 individuals without sleep apnea were matched by sex, age, birth year, and body mass index (within ±0.5 kg/m(2) ). We estimated the incidence rates of gout and examined the relationship between sleep apnea and the risk of incident gout using a Cox proportional hazards model, adjusting for potential confounders. In addition, we assessed the rate difference in gout due to sleep apnea using an additive hazard model.

RESULTS

Among 9,865 patients with newly diagnosed sleep apnea and 43,598 matched individuals without sleep apnea, we identified 270 incident cases of gout over 1 year of followup, resulting in incidence rates of 8.4 per 1,000 person-years and 4.8 per 1,000 person-years, respectively. The crude and multivariable rate ratios of incident gout in patients with sleep apnea were 1.7 (95% confidence interval [95% CI] 1.3, 2.2) and 1.5 (95% CI 1.1, 2.1), respectively. The corresponding rate differences between patients with sleep apnea and the comparison cohort were 3.6 (95% CI 1.6, 5.6) and 2.8 (95% CI 0.7, 4.9) per 1,000 person-years. The effect of sleep apnea persisted across subgroups.

CONCLUSION

This general population-based study indicates that sleep apnea is independently associated with an increased risk of incident gout. Future research should examine the potential benefits of correcting sleep apnea-induced hypoxia on the risk of hyperuricemia and gout flares.

2015 Gout classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative

Objective

Existing criteria for the classification of gout have suboptimal sensitivity and/or specificity, and were developed at a time when advanced imaging was not available. The current effort was undertaken to develop new classification criteria for gout.

Methods

An international group of investigators, supported by the American College of Rheumatology and the European League Against Rheumatism, conducted a systematic review of the literature on advanced imaging of gout, a diagnostic study in which the presence of monosodium urate monohydrate (MSU) crystals in synovial fluid or tophus was the gold standard, a ranking exercise of paper patient cases, and a multi-criterion decision analysis exercise. These data formed the basis for developing the classification criteria, which were tested in an independent data set.

Results

The entry criterion for the new classification criteria requires the occurrence of at least one episode of peripheral joint or bursal swelling, pain, or tenderness. The presence of MSU crystals in a symptomatic joint/bursa (ie, synovial fluid) or in a tophus is a sufficient criterion for classification of the subject as having gout, and does not require further scoring. The domains of the new classification criteria include clinical (pattern of joint/bursa involvement, characteristics and time course of symptomatic episodes), laboratory (serum urate, MSU-negative synovial fluid aspirate), and imaging (double-contour sign on ultrasound or urate on dual-energy CT, radiographic gout-related erosion). The sensitivity and specificity of the criteria are high (92% and 89%, respectively).

Conclusions

The new classification criteria, developed using a data-driven and decision-analytic approach, have excellent performance characteristics and incorporate current state-of-the-art evidence regarding gout.

2015 Gout Classification Criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative

OBJECTIVE

Existing criteria for the classification of gout have suboptimal sensitivity and/or specificity, and were developed at a time when advanced imaging was not available. The current effort was undertaken to develop new classification criteria for gout.

METHODS

An international group of investigators, supported by the American College of Rheumatology and the European League Against Rheumatism, conducted a systematic review of the literature on advanced imaging of gout, a diagnostic study in which the presence of monosodium urate monohydrate (MSU) crystals in synovial fluid or tophus was the gold standard, a ranking exercise of paper patient cases, and a multicriterion decision analysis exercise. These data formed the basis for developing the classification criteria, which were tested in an independent data set.

RESULTS

The entry criterion for the new classification criteria requires the occurrence of at least 1 episode of peripheral joint or bursal swelling, pain, or tenderness. The presence of MSU crystals in a symptomatic joint/bursa (i.e., synovial fluid) or in a tophus is a sufficient criterion for classification of the subject as having gout, and does not require further scoring. The domains of the new classification criteria include clinical (pattern of joint/bursa involvement, characteristics and time course of symptomatic episodes), laboratory (serum urate, MSU-negative synovial fluid aspirate), and imaging (double-contour sign on ultrasound or urate on dual-energy computed tomography, radiographic gout-related erosion). The sensitivity and specificity of the criteria are high (92% and 89%, respectively).

CONCLUSION

The new classification criteria, developed using a data-driven and decision analytic approach, have excellent performance characteristics and incorporate current state-of-the-art evidence regarding gout.

Data mining-based statistical analysis of biological data uncovers hidden significance: clustering Hashimoto's thyroiditis patients based on the response of their PBMC with IL-2 and IFN-γ secretion to stimulation with Hsp60

The pathogenesis of Hashimoto's thyroiditis includes autoimmunity involving thyroid antigens, autoantibodies, and possibly cytokines. It is unclear what role plays Hsp60, but our recent data indicate that it may contribute to pathogenesis as an autoantigen. Its role in the induction of cytokine production, pro- or anti-inflammatory, was not elucidated, except that we found that peripheral blood mononucleated cells (PBMC) from patients or from healthy controls did not respond with cytokine production upon stimulation by Hsp60 in vitro with patterns that would differentiate patients from controls with statistical significance. This "negative" outcome appeared when the data were pooled and analyzed with conventional statistical methods. We re-analyzed our data with non-conventional statistical methods based on data mining using the classification and regression tree learning algorithm and clustering methodology. The results indicate that by focusing on IFN-γ and IL-2 levels before and after Hsp60 stimulation of PBMC in each patient, it is possible to differentiate patients from controls. A major general conclusion is that when trying to identify disease markers such as levels of cytokines and Hsp60, reference to standards obtained from pooled data from many patients may be misleading. The chosen biomarker, e.g., production of IFN-γ and IL-2 by PBMC upon stimulation with Hsp60, must be assessed before and after stimulation and the results compared within each patient and analyzed with conventional and data mining statistical methods.