Uptake of the Gout and Crystal Arthritis Network Consensus Statements for Gout Nomenclature

OBJECTIVE

In 2019, the Gout and Crystal Arthritis Network (G-CAN) published consensus statements for the nomenclature of disease elements and states in gout. The aim of this study was to determine adherence to the G-CAN consensus nomenclature statements since publication.

METHODS

American College of Rheumatology and EULAR conference abstracts were searched using online databases for the keywords 'gout,' 'urate,' 'uric acid,' 'hyperuricaemia,' 'tophus,' and/or 'tophi' before and after publication of the consensus statements (January 1, 2016 to December 31, 2017 and January 1, 2020 to December 31, 2021, respectively). Abstracts were manually searched for labels used to reference gout disease elements and states. Use of the G-CAN-agreed labels, as well as alternatives, were compared between the two time periods.

RESULTS

There were 988 abstracts included in the analysis: 596 in 2016 to 2017 and 392 in 2020 to 2021. Use of the agreed labels 'urate' and 'gout flare' increased between the two periods. There were 219 of 383 abstracts (57.2%) with the agreed label 'urate' in 2016 to 2017 compared with 164 of 232 (70.7%) in 2020 to 2021 (P = 0.001). There were 60 of 175 abstracts (34.3%) with the agreed label 'gout flare' in 2016 to 2017 compared with 57 of 109 (52.3%) in 2020 to 2021 (P = 0.003). Consistent with the G-CAN statement, use of the label 'chronic gout' reduced between the two time periods. There were 29 of 596 abstracts (4.9%) in 2016 to 2017 that used the label 'chronic gout' compared with 8 of 392 abstracts (2.0%) in 2020 to 2021 (P = 0.02).

CONCLUSION

Use of G-CAN-agreed gout labels has increased, but gout nomenclature remains imprecise. Additional efforts are needed to ensure consistent use of agreed nomenclature for gout in the scientific literature.

Comparative risk of gout flares when initiating or escalating various urate-lowering therapy: a systematic review with network meta-analysis

OBJECTIVE

Systematically examine: comparative flare risk post initiation or escalation of different urate-lowering therapies (ULTs); comparative flare risk with and without concomitant flare prophylaxis; adverse event rates associated with flare prophylaxis; and optimal duration of flare prophylaxis.

METHODS

We searched Medline, Embase, Web of Science, Cochrane database and clinical trial registries from inception to November 2021 for trials investigating adults with gout initiating or escalating ULT. We performed random-effects network meta-analyses and calculated risk ratios (RR) between treatments. Bias was assessed using the Revised Cochrane risk-of-bias tool.

RESULTS

We identified 3775 records, of which 29 publications (27 trials) were included. When compared to placebo+prophylaxis, the RR of flares ranged from 1·08 [95% confidence interval (95% CI) 0·87-1·33] for febuxostat 40mg+prophylaxis to 2·65 [95% CI 1·58-4·45] for febuxostat 80mg+lesinurad 400mg+prophylaxis. Compared to ULT alone, the RR of flares was lower for ULT+rilonacept 160mg (RR=0·35 [95% CI 0·25-0·50]), ULT+rilonacept 80mg (RR=0·43 [95% CI 0·31-0·60]) and ULT+colchicine (RR=0·50 [95% CI 0·35-0·72]). There was limited evidence for other flare prophylaxis, and on prophylaxis harms and optimal duration. Primarily due to missing outcome data and bias in the selection of reported results, 71·4% and 63·4% of studies were assessed as high risk of bias for flares and adverse events respectively.

CONCLUSION

The relative risk of flares when introducing ULT varies depending on ULT drug and dosing strategy. There was limited data on ULT escalation. Flare prophylaxis with colchicine and rilonacept reduces flare incidence. More research is required on the harms and optimal duration of prophylaxis.

Intensive serum urate lowering with oral urate-lowering therapy for erosive gout: A randomized double-blind controlled trial

OBJECTIVE

To determine whether intensive serum urate lowering results in improved bone erosion scores in erosive gout.

METHODS

Two-year, double-blind, randomized, controlled trial of 104 participants with erosive gout on oral urate-lowering therapy (ULT) and serum urate ≥ 0.30mmol/L was undertaken. Participants were randomly assigned to serum urate target <0.20mmol/L (intensive target) or <0.30mmol/L (standard target, according to rheumatology guidelines). Oral ULT was titrated to target using a standardized protocol (using maximum approved doses of allopurinol, probenecid, febuxostat, and benzbromarone). The primary endpoint was total CT erosion score. OMERACT gout core outcome domains were secondary endpoints.

RESULTS

Although the serum urate was significantly lower in the intensive target group compared to the standard target group (P=0.002), fewer participants in the intensive group achieved the randomized serum urate target (at Year 2, 62% vs 83%, P<0.05). The intensive target group required higher allopurinol doses (mean (SD) 746 (210) mg/day vs 496 (185) mg/day, P<0.001), and used more combination therapy (P=0.0004). Small increases in CT erosion scores were observed in both groups over two years, with no between-group difference (P=0.20). OMERACT core outcome domains (gout flares, tophus, pain, patient global assessment, health-related quality of life, and activity limitation) improved in both groups, with no between-group differences. Adverse event and serious adverse event rates were similar between groups.

CONCLUSION

Compared with a serum urate target below 0.30mmol/L, more intensive serum urate-lowering is difficult to achieve with oral ULT, leads to high medication burden, and does not improve bone erosion scores in erosive gout.

Gout, Hyperuricemia, and Crystal-Associated Disease Network Consensus Statement Regarding Labels and Definitions for Disease Elements in Gout

OBJECTIVE

The language currently used to describe gout lacks standardization. The aim of this project was to develop a consensus statement on the labels and definitions used to describe the basic disease elements of gout.

METHODS

Experts in gout (n = 130) were invited to participate in a Delphi exercise and face-to-face consensus meeting to reach consensus on the labeling and definitions for the basic disease elements of gout. Disease elements and labels in current use were derived from a content analysis of the contemporary medical literature, and the results of this analysis were used for item selection in the Delphi exercise and face-to-face consensus meeting.

RESULTS

There were 51 respondents to the Delphi exercise and 30 attendees at the face-to-face meeting. Consensus agreement (≥80%) was achieved for the labels of 8 disease elements through the Delphi exercise; the remaining 3 labels reached consensus agreement through the face-to-face consensus meeting. The agreed labels were monosodium urate crystals, urate, hyperuric(a)emia, tophus, subcutaneous tophus, gout flare, intercritical gout, chronic gouty arthritis, imaging evidence of monosodium urate crystal deposition, gouty bone erosion, and podagra. Participants at the face-to-face meeting achieved consensus agreement for the definitions of all 11 elements and a recommendation that the label "chronic gout" should not be used.

CONCLUSION

Consensus agreement was achieved for the labels and definitions of 11 elements representing the fundamental components of gout etiology, pathophysiology, and clinical presentation. The Gout, Hyperuricemia, and Crystal-Associated Disease Network recommends the use of these labels when describing the basic disease elements of gout.

Gout, Hyperuricaemia and Crystal-Associated Disease Network (G-CAN) consensus statement regarding labels and definitions of disease states of gout

OBJECTIVE

There is a lack of standardisation in the terminology used to describe gout. The aim of this project was to develop a consensus statement describing the recommended nomenclature for disease states of gout.

METHODS

A content analysis of gout-related articles from rheumatology and general internal medicine journals published over a 5-year period identified potential disease states and the labels commonly assigned to them. Based on these findings, experts in gout were invited to participate in a Delphi exercise and face-to-face consensus meeting to reach agreement on disease state labels and definitions.

RESULTS

The content analysis identified 13 unique disease states and a total of 63 unique labels. The Delphi exercise (n=76 respondents) and face-to-face meeting (n=35 attendees) established consensus agreement for eight disease state labels and definitions. The agreed labels were as follows: 'asymptomatic hyperuricaemia', 'asymptomatic monosodium urate crystal deposition', 'asymptomatic hyperuricaemia with monosodium urate crystal deposition', 'gout', 'tophaceous gout', 'erosive gout', 'first gout flare' and 'recurrent gout flares'. There was consensus agreement that the label 'gout' should be restricted to current or prior clinically evident disease caused by monosodium urate crystal deposition (gout flare, chronic gouty arthritis or subcutaneous tophus).

CONCLUSION

Consensus agreement has been established for the labels and definitions of eight gout disease states, including 'gout' itself. The Gout, Hyperuricaemia and Crystal-Associated Disease Network recommends the use of these labels when describing disease states of gout in research and clinical practice.

Prevalence of minimal disease activity in Australian patients with Psoriatic Arthritis: Assessing the outcome of national funding criteria for biologic disease-modifying antirheumatic drug prescribing

AIM

Discrepancies exist between international treatment guidelines and current Australian Pharmaceutical Benefits Scheme (PBS) criteria for funding biologic disease-modifying antirheumatic drug (bDMARD) prescribing in psoriatic arthritis (PsA). We aimed to determine the prevalence of minimal disease activity (MDA) achievement and differences in inflammatory marker levels between PsA patients who have and have not met the Australian PBS criteria for bDMARDs.

METHOD

Consecutive participants diagnosed with PsA were assessed for MDA components and serum inflammatory markers. For those on bDMARDs, joint counts and inflammatory markers at the time of bDMARD qualification were compared with matched rheumatoid arthritis (RA) controls.

RESULTS

Minimal disease activity was achieved by 56/105 participants overall. There were no differences in inflammatory marker levels or involved joint count patterns between the PsA and RA groups at the time of bDMARD qualification. Seventy-three percent of the 53 PsA patients on bDMARD achieved MDA, vs 33% in the non-bDMARD group (P < 0.001). More bDMARD than non-bDMARD patients achieved four out of seven MDA components. Of those with any enthesitis, its prevalence was higher in the non-bDMARD group (22 vs 10, P = 0.009). Regardless of treatment, there was no difference in inflammatory marker levels between those who did and did not achieve MDA.

CONCLUSION

The Australian PBS criteria, funding bDMARD prescribing for PsA, select well for MDA achievers. A high prevalence of MDA non-achievement remains in patients ineligible for bDMARD funding, and enthesitis in this population is more common. Inflammatory markers were not discriminators between treatment or MDA achievement groups.

The nomenclature of the basic disease elements of gout: A content analysis of contemporary medical journals

OBJECTIVES

There is currently no standardised nomenclature for the basic disease elements of gout. This study aimed to identify these elements and examine how they are labelled in contemporary medical literature.

METHODS

We analysed articles from the ten highest ranked general rheumatology journals, and five highest ranked general internal medicine journals (by Impact Factor, according to 2015 Thomson-Reuters Journal Citation Reports), published between 1 January 2012 and 31 January 2017. For each journal, articles relevant to gout and hyperuricaemia were identified by the search terms 'gout' and/or 'urate' and/or 'uric acid' using MEDLINE. Basic disease elements were identified and their labels extracted. Labels designated 'unique' used different words or phrases to describe an element.

RESULTS

A total of 549 articles were analysed. Eleven basic disease elements and 343 unique labels were identified. Labelling was imprecise for most elements. 'An episode of acute inflammation triggered by the presence of pathogenic crystals' was represented by a total of 162 unique labels; 33.6% of articles referring to this element used at least four unique labels. For articles referencing 'the circulating form of the final enzymatic product generated by xanthine oxidase in purine metabolism in humans', the labels 'uric acid' and 'urate' were used with similar frequency (63.0% and 62.5%, respectively), and both labels were used in 25.9% of articles.

CONCLUSION

Labelling of the basic disease elements of gout is characterised by imprecision, inaccuracy and lack of clarity. Consensus regarding the nomenclature of these elements is required.

What Is the Evidence for Treat-to-Target Serum Urate in Gout?

PURPOSE OF REVIEW

Most current clinical guidelines for gout management advocate a treat-to-target serum urate approach, although notable differences exist. Serum urate is a rational target for gout treatment given the central role of urate in disease causality, its association with key outcomes and its practicality of use in clinical practice. This review analyses the evidence for this strategy in gout.

RECENT FINDINGS

Recent studies have confirmed the efficacy of urate-lowering therapy in achieving serum urate targets, both in trials using fixed doses and those applying a treat-to-target strategy. In a limited number of long-term studies (> 12-month duration), interventions that incorporate a treat-to-target serum urate approach have been shown to promote regression of tophi, reduce the frequency of gout flares and improve MRI-detected synovitis. A strong case can be made for a treat-to-target serum urate strategy in gout, supported by existing knowledge of disease pathophysiology, outcomes from urate-lowering therapy studies and emerging results of randomised strategy trials of sufficient duration.

Generic microcystin immunoassay based on monoclonal antibodies against Adda

A monoclonal antibody (clone AD4G2) was generated against a common part of microcystins and nodularins, the unusual amino acid Adda [(2S,3S,8S,9S)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4E,6E-dienoic acid]. A direct competitive ELISA based on this antibody was developed and the cross-reactivity pattern was measured. Different toxins showed a very similar response. The assay provides therefore a sum parameter of microcystins, nodularins and peptide fragments containing Adda. The IC50 for microcystin-LR was 0.33 microg L(-1) which leads to a detection limit of 0.07 microg L(-1). This is well below the concentration of 1 microg L(-1) proposed by the World Health Organisation (WHO) as the limit for drinking water. Microcystin-LR spiked water samples in the concentration range between 0.1 and 1 microg L(-1) were measured and a mean recovery of 113+/-23% was found. The antibody is well suited for the determination of microcystins in drinking as well as surface water.

Electromyographic feedback in the remobilization of stroke patients: a controlled trial

Electromyographic biofeedback was compared with simple exercise therapy as to its effectiveness in improving foot-drop in 22 stroke patients. The study was designed to be a rigorous trial of biofeedback and the patients tested were aged and had stroke of long duration. One group of 11 patients underwent 6 weeks of exercise therapy 2 sessions per week for 15 minutes per session; the 2nd group of 11 patients underwent similar therapy with EMG feedback. All therapy was conducted by a research assistant who was not a trained therapist. The groups were assessed blind before treatment, after treatment and a 6-week follow-up. The significantly greater improvements in the biofeedback group in terms of muscle strength at the end of treatment were maintained at follow-up. On the range of movement and gait analysis measures, both groups showed some improvement after treatment. However, at follow-up this improvement had relapsed for the exercise group while for the biofeedback group it had been maintained. It is argued that controlled trials are possible in biofeedback and that using patients as their own controls is not justified in view of the present findings and the previously reported literature.