Preliminary criteria for the classification of the acute arthritis of primary gout

The American Rheumatism Association sub-committe on classification criteria for gout analyzed data from more than 700 patients with gout, pseudogout, rheumatoid arthritis, or septic arthritis. Criteria for classifying a patient as having gout were a) the presence of characteristic urate crystals in the joint fluid, and/or b) a topus proved to contain urate crystals by chemical or polarized light microscopic means, and/or c) the presence of six of the twelve clinical, laboratory, and X-ray phenomena listed in Table 5.

Gout

Gout is a chronic disease of deposition of monosodium urate crystals, which form in the presence of increased urate concentrations. Although environmental factors contribute to hyperuricaemia, renal and gut excretion of urate is central to regulation of serum urate, and genetic factors are important. Activation of the NLRP3 inflammasome and release of interleukin 1β have key roles in initiation of acute gout flares. A "treat to target serum urate" approach is essential for effective gout management; long-term lowering of serum urate to less than 360 μmol/L leads to crystal dissolution and ultimately to suppression of flares. An allopurinol dose-escalation strategy is frequently effective for achieving treatment targets, and several new urate-lowering drugs are also available. Worldwide, rates of initiation and continuation of urate-lowering therapy are very low, and, consequently, achievement of serum urate targets is infrequent. Strategies to improve quality of gout care are needed.

Gout

Gout is a common arthritis caused by deposition of monosodium urate crystals within joints after chronic hyperuricaemia. It affects 1-2% of adults in developed countries, where it is the most common inflammatory arthritis in men. Epidemiological data are consistent with a rise in prevalence of gout. Diet and genetic polymorphisms of renal transporters of urate seem to be the main causal factors of primary gout. Gout and hyperuricaemia are associated with hypertension, diabetes mellitus, metabolic syndrome, and renal and cardiovascular diseases. Non-steroidal anti-inflammatory drugs and colchicine remain the most widely recommended drugs to treat acute attacks. Oral corticosteroids could be an alternative to these drugs. Interleukin 1beta is a pivotal mediator of acute gout and could become a therapeutic target. When serum uric acid concentrations are lowered below monosodium urate saturation point, the crystals dissolve and gout can be cured. Patient education, appropriate lifestyle advice, and treatment of comorbidities are an important part of management of patients with gout.

Gout

Gout is a common and treatable disease caused by the deposition of monosodium urate crystals in articular and non-articular structures. Increased concentration of serum urate (hyperuricaemia) is the most important risk factor for the development of gout. Serum urate is regulated by urate transporters in the kidney and gut, particularly GLUT9 (SLC2A9), URAT1 (SLC22A12), and ABCG2. Activation of the NLRP3 inflammasome by monosodium urate crystals with release of IL-1β plays a major role in the initiation of the gout flare; aggregated neutrophil extracellular traps are important in the resolution phase. Although presenting as an intermittent flaring condition, gout is a chronic disease. Long-term urate lowering therapy (eg, allopurinol) leads to the dissolution of monosodium urate crystals, ultimately resulting in the prevention of gout flares and tophi and in improved quality of life. Strategies such as nurse-led care are effective in delivering high-quality gout care and lead to major improvements in patient outcomes.

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.

EULAR evidence based recommendations for gout. Part I: Diagnosis. Report of a task force of the Standing Committee for International Clinical Studies Including Therapeutics (ESCISIT)

OBJECTIVE

To develop evidence based recommendations for the diagnosis of gout.

METHODS

The multidisciplinary guideline development group comprised 19 rheumatologists and one evidence based medicine expert, representing 13 European countries. Ten key propositions regarding diagnosis were generated using a Delphi consensus approach. Research evidence was searched systematically for each proposition. Wherever possible the sensitivity, specificity, likelihood ratio (LR), and incremental cost-effectiveness ratio were calculated for diagnostic tests. Relative risk and odds ratios were estimated for risk factors and co-morbidities associated with gout. The quality of evidence was categorised according to the evidence hierarchy. The strength of recommendation (SOR) was assessed using the EULAR visual analogue and ordinal scales.

RESULTS

10 key propositions were generated though three Delphi rounds including diagnostic topics in clinical manifestations, urate crystal identification, biochemical tests, radiographs, and risk factors/co-morbidities. Urate crystal identification varies according to symptoms and observer skill but is very likely to be positive in symptomatic gout (LR = 567 (95% confidence interval (CI), 35.5 to 9053)). Classic podagra and presence of tophi have the highest clinical diagnostic value for gout (LR = 30.64 (95% CI, 20.51 to 45.77), and LR = 39.95 (21.06 to 75.79), respectively). Hyperuricaemia is a major risk factor for gout and may be a useful diagnostic marker when defined by the normal range of the local population (LR = 9.74 (7.45 to 12.72)), although some gouty patients may have normal serum uric acid concentrations at the time of investigation. Radiographs have little role in diagnosis, though in late or severe gout radiographic changes of asymmetrical swelling (LR = 4.13 (2.97 to 5.74)) and subcortical cysts without erosion (LR = 6.39 (3.00 to 13.57)) may be useful to differentiate chronic gout from other joint conditions. In addition, risk factors (sex, diuretics, purine-rich foods, alcohol, lead) and co-morbidities (cardiovascular diseases, hypertension, diabetes, obesity, and chronic renal failure) are associated with gout. SOR for each proposition varied according to both the research evidence and expert opinion.

CONCLUSIONS

10 key recommendations for diagnosis of gout were developed using a combination of research based evidence and expert consensus. The evidence for diagnostic tests, risk factors, and co-morbidities was evaluated and the strength of recommendation was provided.

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.

Autosomal dominant tubulointerstitial kidney disease: diagnosis, classification, and management--A KDIGO consensus report

Rare autosomal dominant tubulointerstitial kidney disease is caused by mutations in the genes encoding uromodulin (UMOD), hepatocyte nuclear factor-1β (HNF1B), renin (REN), and mucin-1 (MUC1). Multiple names have been proposed for these disorders, including 'Medullary Cystic Kidney Disease (MCKD) type 2', 'Familial Juvenile Hyperuricemic Nephropathy (FJHN)', or 'Uromodulin-Associated Kidney Disease (UAKD)' for UMOD-related diseases and 'MCKD type 1' for the disease caused by MUC1 mutations. The multiplicity of these terms, and the fact that cysts are not pathognomonic, creates confusion. Kidney Disease: Improving Global Outcomes (KDIGO) proposes adoption of a new terminology for this group of diseases using the term 'Autosomal Dominant Tubulointerstitial Kidney Disease' (ADTKD) appended by a gene-based subclassification, and suggests diagnostic criteria. Implementation of these recommendations is anticipated to facilitate recognition and characterization of these monogenic diseases. A better understanding of these rare disorders may be relevant for the tubulointerstitial fibrosis component in many forms of chronic kidney disease.

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.

Gout: why is this curable disease so seldom cured?

Gout is the most common inflammatory arthritis and one in which pathogenesis and risk factors are best understood. One of the treatment objectives in current guidelines is 'cure'. However, audits show that only a minority of patients with gout receive adequate advice and treatment. Suboptimal care and outcomes reflect inappropriately negative perceptions of the disease, both in patients and providers. Historically, gout has been portrayed as a benign and even comical condition that is self-inflicted through overeating and alcohol excess. Doctors often focus on managing acute attacks rather than viewing gout as a chronic progressive crystal deposition disease. Urate-lowering treatment is underprescribed and often underdosed. Appropriate education of patients and doctors, catalysed by recent introduction of new urate-lowering treatments after many years with no drug development in the field, may help to overcome these barriers and improve management of this easily diagnosed and curable form of potentially severe arthritis.

Dual-energy CT for the diagnosis of gout: an accuracy and diagnostic yield study

OBJECTIVES

To assess the accuracy of dual-energy CT (DECT) for diagnosing gout, and to explore whether it can have any impact on clinical decision making beyond the established diagnostic approach using polarising microscopy of synovial fluid (diagnostic yield).

METHODS

Diagnostic single-centre study of 40 patients with active gout, and 41 individuals with other types of joint disease. Sensitivity and specificity of DECT for diagnosing gout was calculated against a combined reference standard (polarising and electron microscopy of synovial fluid). To explore the diagnostic yield of DECT scanning, a third cohort was assembled consisting of patients with inflammatory arthritis and risk factors for gout who had negative synovial fluid polarising microscopy results. Among these patients, the proportion of subjects with DECT findings indicating a diagnosis of gout was assessed.

RESULTS

The sensitivity and specificity of DECT for diagnosing gout was 0.90 (95% CI 0.76 to 0.97) and 0.83 (95% CI 0.68 to 0.93), respectively. All false negative patients were observed among patients with acute, recent-onset gout. All false positive patients had advanced knee osteoarthritis. DECT in the diagnostic yield cohort revealed evidence of uric acid deposition in 14 out of 30 patients (46.7%).

CONCLUSIONS

DECT provides good diagnostic accuracy for detection of monosodium urate (MSU) deposits in patients with gout. However, sensitivity is lower in patients with recent-onset disease. DECT has a significant impact on clinical decision making when gout is suspected, but polarising microscopy of synovial fluid fails to demonstrate the presence of MSU crystals.

The value of synovial fluid assays in the diagnosis of joint disease: a literature survey

OBJECTIVE

To carry out a critical appraisal of the literature in an attempt to assess the current value of synovial fluid (SF) analysis in the diagnosis of joint disease.

METHODS

A literature search was undertaken using the Medline, Biomed, Bids, Pubmed, and Embase electronic databases using the keywords: synovial fluid (SF) analysis, SF crystals, joint sepsis, acute arthritis, and SF cell counts, cytology, biomarkers, and microbiology.

RESULTS

Publications fell into three main categories. Firstly, reports assessing the value of the three traditional assays (microbiology, white blood cell counts, and microscopy for pathogenic crystals). For these quality control evidence was found to be sparse, and tests for sensitivity, specificity, and reliability showed worrying variations. These poor standards in SF analysis may be due to lack of inclusion of some tests within routine pathology services. Secondly, claims for the usefulness of "new" assays (cytology and biochemical markers). For cytology, the supporting evidence was mainly anecdotal and there were no reports on specificity, sensitivity, and reliability. Interpretation difficulties are a major hindrance to the clinical use of biochemical assays, which remain primarily research tools. Finally, work on the diagnostic value of SF analysis in general. The appraisal confirmed that SF analysis remains of major diagnostic value in acute arthritis, where septic arthritis or crystal arthropathy is suspected, and in intercritical gout.

CONCLUSIONS

Given the importance of SF tests, rationalisation of their use, together with improved quality control, should be immediate priorities. Further investigation is recommended into the contribution of SF inspection and white cell counts to diagnosis, as well as of the specificity and sensitivity of SF microbiological assays, crystal identification, and cytology.

Multinational evidence-based recommendations for the diagnosis and management of gout: integrating systematic literature review and expert opinion of a broad panel of rheumatologists in the 3e initiative

We aimed to develop evidence-based multinational recommendations for the diagnosis and management of gout. Using a formal voting process, a panel of 78 international rheumatologists developed 10 key clinical questions pertinent to the diagnosis and management of gout. Each question was investigated with a systematic literature review. Medline, Embase, Cochrane CENTRAL and abstracts from 2010-2011 European League Against Rheumatism and American College of Rheumatology meetings were searched in each review. Relevant studies were independently reviewed by two individuals for data extraction and synthesis and risk of bias assessment. Using this evidence, rheumatologists from 14 countries (Europe, South America and Australasia) developed national recommendations. After rounds of discussion and voting, multinational recommendations were formulated. Each recommendation was graded according to the level of evidence. Agreement and potential impact on clinical practice were assessed. Combining evidence and clinical expertise, 10 recommendations were produced. One recommendation referred to the diagnosis of gout, two referred to cardiovascular and renal comorbidities, six focused on different aspects of the management of gout (including drug treatment and monitoring), and the last recommendation referred to the management of asymptomatic hyperuricaemia. The level of agreement with the recommendations ranged from 8.1 to 9.2 (mean 8.7) on a 1-10 scale, with 10 representing full agreement. Ten recommendations on the diagnosis and management of gout were established. They are evidence-based and supported by a large panel of rheumatologists from 14 countries, enhancing their utility in clinical practice.

The spectrum of inherited mutations causing HPRT deficiency: 75 new cases and a review of 196 previously reported cases

In humans, mutations in the gene encoding the purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT) are associated with a spectrum of disease that ranges from hyperuricemia alone to hyperuricemia with profound neurological and behavioral dysfunction. Previous attempts to correlate different types or locations of mutations with different elements of the disease phenotype have been limited by the relatively small numbers of available cases. The current article describes the molecular genetic basis for 75 new cases of HPRT deficiency, reviews 196 previously reported cases, and summarizes four main conclusions that may be derived from the entire database of 271 mutations. First, the mutations associated with human disease appear dispersed throughout the hprt gene, with some sites appearing to represent relative mutational hot spots. Second, genotype-phenotype correlations provide no indication that specific disease features associate with specific mutation locations. Third, cases with less severe clinical manifestations typically have mutations that are predicted to permit some degree of residual enzyme function. Fourth, the nature of the mutation provides only a rough guide for predicting phenotypic severity. Though mutation analysis does not provide precise information for predicting disease severity, it continues to provide a valuable tool for genetic counseling in terms of confirmation of diagnoses, for identifying potential carriers, and for prenatal diagnosis.

Synovial fluid analysis for diagnosis of intercritical gout

BACKGROUND

The diagnosis of gout in the intercritical phase can be difficult.

OBJECTIVE

To determine whether synovial fluid analysis allows the diagnosis of intercritical gout.

DESIGN

Cross-sectional study.

SETTING

Outpatient rheumatology clinics.

PATIENTS

101 patients with gout.

INTERVENTION

Arthrocentesis of 80 knees and 21 first metatarsophalangeal joints (each joint from a different patient) that had been inflamed but were currently asymptomatic.

MEASUREMENTS

Frequency with which arthrocentesis yielded synovial fluid; presence of monosodium urate crystals in the synovial fluid sample; and, for synovial fluid with crystals, the number of microscope fields that had to be scanned before crystals were found.

RESULTS

Synovial fluid was obtained from 91 of 101 joints. The fluid from all 43 patients not receiving hypouricemic agents contained monosodium urate crystals. These crystals were found in the synovial fluid of only 34 of 48 patients receiving hypouricemic agents. In 90% of the synovial fluid samples that contained crystals, crystals were seen in the first five microscope fields examined.

CONCLUSIONS

Arthrocentesis of asymptomatic knees and first metatarsophalangeal joints and synovial fluid analysis are simple procedures that facilitate the diagnosis of gout during intercritical periods.

Synovial membrane histopathology in the differential diagnosis of rheumatoid arthritis, gout, pseudogout, systemic lupus erythematosus, infectious arthritis and degenerative joint disease

The synovial membrane histologic sections from patients with six common rheumatic diseases were reviewed without knowledge of the clinical diagnosis. After histopathologic evaluation, the synovial membrane characteristics were grouped according to the patient's clinical diagnosis, and included 29 patients with rheumatoid arthritis, 13 with systemic lupus erythematosus, 17 with degenerative joint disease, 10 with acute bacterial arthritis, 8 with gout, and 13 with pseudogout. The only specific characteristics identified were bacteria (infectious arthritis), crystals (gout, pseudogout), and lymphoid follicles (rheumatoid arthritis). Nevertheless, other characteristic features of differential diagnostic utility were recognized, including the intensity and nature of synovial lining cell hyperplasia and of leukocyte infiltration. Light microscopic histopathologic changes in the common rheumatic diseases are not specific, but are of diagnostic utility. Complete and exhaustive review of each pathologic synovial membrane characteristic provides more justification for the routine use of synovial membrane biopsy as an adjunct to arthrocentesis in the evaluation of common rheumatic diseases.

Xanthine oxidase inhibitors for prevention of cardiovascular events: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Xanthine oxidase inhibitors (XOI), classified as purine-like (allopurinol and oxypurinol) and non-purine (febuxostat and topiroxostat) XOI, present antioxidant properties by reducing the production of reactive oxygen species derived from purine metabolism. Oxidative stress is an important factor related to endothelial dysfunction and ischemia-reperfusion injury, and may be implicated in the pathogenesis of heart failure, hypertension, and ischemic heart disease. However, there is contradictory evidence regarding the possible cardiovascular (CV) protective effect exerted by XOI. Our objective is to compare the incidence of major adverse cardiovascular events (MACE), mortality, total (TCE) and specific CV events in randomized controlled trials (RCTs) testing XOI against placebo or no treatment.

METHODS

PubMed, EMBASE, Web of Science, Cochrane Central, Lilacs databases were searched from inception to Dec 30 2016, along with hand searching. RCTs including exclusively adult individuals, lasting ≥ 4 weeks, with no language restriction, were eligible. Independent paired researchers selected studies and extracted data. Considering the expected rarity of events, Peto and DerSimonian/Laird odds ratios (OR), the latter in case of heterogeneity, were used for analysis. Random-effects meta-regression was used to explore heterogeneity.

RESULTS

The analysis of MACE included 81 articles (10,684 patients, 6434 patient-years). XOI did not significantly reduce risk of MACE (ORP = 0.71, 95% CI 0.46-1.09) and death (0.89, 0.59-1.33), but reduced risk of TCE (0.60, 0.44-0.82; serious TCE: 0.64, 0.46 to 0.89), and hypertension (0.54, 0.37 to 0.80). There was protection for MACE in patients with previous ischemic events (0.42, 0.23-0.76). Allopurinol protected for myocardial infarction (0.38, 0.17-0.83), hypertension (0.32, 0.18-0.58), TCE (0.48, 0.31 to 0.75, I2 = 55%) and serious TCE (0.56, 0.36 to 0.86, I2 = 44%). Meta-regression associated increasing dose of allopurinol with higher risk of TCE and serious TCE (P < 0.05). Accordingly, lower doses (≤ 300 mg/day) of allopurinol reduced the risk of TCE, unlike higher doses. Non-purine-like XOI did not significantly reduce or increase the risk of adverse CV events, but confidence intervals were wide. Quality of evidence was generally low to moderate.

CONCLUSIONS

Purine-like XOI may reduce the incidence of adverse CV outcomes. However, higher doses of allopurinol (> 300 mg/day) may be associated with loss of CV protection.

Imaging modalities for the classification of gout: systematic literature review and meta-analysis

BACKGROUND

Although there has been major progress in gout imaging, no gout classification criteria currently include advanced imaging techniques.

OBJECTIVE

To examine the usefulness of imaging modalities in the classification of gout when compared to monosodium urate (MSU) crystal confirmation as the gold standard, in order to inform development of new gout classification criteria.

METHODS

We systematically reviewed the published literature concerning the diagnostic performance of plain film radiography, MRI, ultrasound (US), conventional CT and dual energy CT (DECT). Only studies with MSU crystal confirmation as the gold standard were included. When more than one study examined the same imaging feature, the data were pooled and summary test characteristics were calculated.

RESULTS

11 studies (9 manuscripts and 2 meeting abstracts) satisfied the inclusion criteria. All were set in secondary care, with mean gout disease duration of at least 7 years. Three features were examined in more than one study: the double contour sign (DCS) on US, tophus on US, and MSU crystal deposition on DECT. The pooled (95% CI) sensitivity and specificity of US DCS were 0.83 (0.72 to 0.91) and 0.76 (0.68 to 0.83), respectively; of US tophus, were 0.65 (0.34 to 0.87) and 0.80 (0.38 to 0.96), respectively; and of DECT, were 0.87 (0.79 to 0.93) and 0.84 (0.75 to 0.90), respectively.

CONCLUSIONS

US and DECT show promise for gout classification but the few studies to date have mostly been in patients with longstanding, established disease. The contribution of imaging over clinical features for gout classification criteria requires further examination.

Diseases associated with calcium pyrophosphate deposition disease

Although many metabolic and endocrine diseases have been reported to predispose to calcium pyrophosphate dihydrate crystal deposition, the validity of many of these associations remains unclear. A critical review of the literature relating to these associations, with illustrative cases and data derived from the authors' own experience, is presented. It is concluded that there is good evidence to associate hypophosphatasia, hypomagnesemia, and hyperparathyroidism with chondrocalcinosis and acute attacks of "pseudogout." Meta-analysis also suggests a small but significant association between hypothyroidism and chondrocalcinosis. Hemochromatosis stands alone in clearly associating not only with chondrocalcinosis but also with structural change and chronic arthropathy. The biochemical mechanisms that may produce these various associations are discussed. Recommendations are made concerning appropriate screening for metabolic and endocrine disease in patients with chondrocalcinosis.

Imaging of tophaceous gout: computed tomography provides specific images compared with magnetic resonance imaging and ultrasonography

OBJECTIVE

To determine the usefulness of computed tomography (CT), magnetic resonance imaging (MRI), and Doppler ultrasonography (US) in providing specific images of gouty tophi.

METHODS

Four male patients with chronic gout with tophi affecting the knee joints (three cases) or the olecranon processes of the elbows (one case) were assessed. Crystallographic analyses of the synovial fluid or tissue aspirates of the areas of interest were made with polarising light microscopy, alizarin red staining, and x ray diffraction. CT was performed with a GE scanner, MR imaging was obtained with a 1.5 T Magneton (Siemens), and ultrasonography with colour Doppler was carried out by standard technique.

RESULTS

Crystallographic analyses showed monosodium urate (MSU) crystals in the specimens of the four patients; hydroxyapatite and calcium pyrophosphate dihydrate (CPPD) crystals were not found. A diffuse soft tissue thickening was seen on plain radiographs but no calcifications or ossifications of the tophi. CT disclosed lesions containing round and oval opacities, with a mean density of about 160 Hounsfield units (HU). With MRI, lesions were of low to intermediate signal intensity on T(1) and T(2) weighting. After contrast injection in two cases, enhancement of the tophus was seen in one. Colour Doppler US showed the tophi to be hypoechogenic with peripheral increase of the blood flow in three cases.

CONCLUSION

The MR and colour Doppler US images showed the tophi as masses surrounded by a hypervascular area, which cannot be considered as specific for gout. But on CT images, masses of about 160 HU density were clearly seen, which correspond to MSU crystal deposits.

Sex differences in gout epidemiology: evaluation and treatment

BACKGROUND

Little is known about the characteristics, evaluation and treatment of women with gout.

OBJECTIVE

To examine the epidemiological differences and differences in treatment between men and women in a large patient population.

METHODS

The data from approximately 1.4 million people who were members of seven managed care plans in the USA for at least 1 year between 1 January 1999 and 31 December 2003 were examined. Adult members who had pharmacy benefits and at least two ambulatory claims specifying a diagnosis of gout were identified. In addition, men and women who were new users of urate-lowering drugs (ULDs) were identified to assess adherence with recommended surveillance of serum urate levels within 6 months of initiating urate-lowering treatment.

RESULTS

A total of 6133 people (4975 men and 1158 women) with two or more International Classification of Disease-9 codes for gout were identified. As compared with men with gout, women were older (mean age 70 (SD 13) v 58 (SD 14), p<0.001) and had comorbidities and received diuretics more often (77% v 40%; p<0.001). Only 37% of new users of urate-lowering treatment had appropriate surveillance of serum urate levels post-initiation of urate-lowering treatment. After controlling for age, comorbidities, gout treatments, number of ULD dispensings and health plan, women were more likely (odds ratio 1.36, 95% confidence interval 1.11 to 1.67) to receive the recommended serum urate level testing.

CONCLUSIONS

Women with gout were older, had greater comorbidities and more often used diuretics and received appropriate surveillance of serum urate levels, suggesting that the factors leading to gout as well as monitoring of treatment are very different in women and men.

Diagnosis and treatment for hyperuricemia and gout: a systematic review of clinical practice guidelines and consensus statements

OBJECTIVES

Despite the publication of hundreds of trials on gout and hyperuricemia, management of these conditions remains suboptimal. We aimed to assess the quality and consistency of guidance documents for gout and hyperuricemia.

DESIGN

Systematic review and quality assessment using the appraisal of guidelines for research and evaluation (AGREE) II methodology.

DATA SOURCES

PubMed and EMBASE (27 October 2016), two Chinese academic databases, eight guideline databases, and Google and Google scholar (July 2017).

ELIGIBILITY CRITERIA

We included the latest version of international and national/regional clinical practice guidelines and consensus statements for diagnosis and/or treatment of hyperuricemia and gout, published in English or Chinese.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently screened searched items and extracted data. Four reviewers independently scored documents using AGREE II. Recommendations from all documents were tabulated and visualised in a coloured grid.

RESULTS

Twenty-four guidance documents (16 clinical practice guidelines and 8 consensus statements) published between 2003 and 2017 were included. Included documents performed well in the domains of scope and purpose (median 85.4%, range 66.7%-100.0%) and clarity of presentation (median 79.2%, range 48.6%-98.6%), but unsatisfactory in applicability (median 10.9%, range 0.0%-66.7%) and editorial independence (median 28.1%, range 0.0%-83.3%). The 2017 British Society of Rheumatology guideline received the highest scores. Recommendations were concordant on the target serum uric acid level for long-term control, on some indications for urate-lowering therapy (ULT), and on the first-line drugs for ULT and for acute attack. Substantially inconsistent recommendations were provided for many items, especially for the timing of initiation of ULT and for treatment for asymptomatic hyperuricemia.

CONCLUSIONS

Methodological quality needs improvement in guidance documents on gout and hyperuricemia. Evidence for certain clinical questions is lacking, despite numerous trials in this field. Promoting standard guidance development methods and synthesising high-quality clinical evidence are potential approaches to reduce recommendation inconsistencies.

PROSPERO REGISTRATION NUMBER

CRD42016046104.