Retrospective longitudinal assessment of ultrasound gout lesions using the OMERACT semi-quantitative scoring system

OBJECTIVES

The objectives of this study were (i) to evaluate the responsiveness of gout-specific US lesions representing urate deposition in patients receiving treat-to-target urate-lowering therapy using a binary and the OMERACT-defined semi-quantitative scoring systems; (ii) to determine the most responsive US measure for urate deposition and the optimal joint/tendon set for monitoring this.

METHODS

US (28 joints, 14 tendons) was performed in microscopically verified gout patients initiating/increasing urate-lowering therapy and repeated after 6 and 12 months. Static images/videos of pathologies were stored and scored binarily and semi-quantitatively for tophus, double contour sign (DC) and aggregates. Lesion scores were calculated at patient level, as were combined crystal sum scores. Responsiveness of lesions-scored binarily and semi-quantitatively-was calculated at both patient and joint/tendon levels.

RESULTS

Sixty-three patients underwent longitudinal evaluation. The static images/videos assessed retrospectively showed statistically significant decreases in tophus and DC, when scored binarily and semi-quantitatively, whereas aggregates were almost unchanged during follow-up. The responsiveness of the semi-quantitative tophus and DC sum scores were markedly higher than when using binary scoring. The most responsive measure for urate deposition was a combined semi-quantitative tophus-DC-sum score. A feasible joint/tendon set for monitoring included knee and first-second MTP joints and peroneus and distal patella tendons (all bilateral), representing the most prevalent and responsive sites.

CONCLUSION

The OMERACT consensus-based semi-quantitative US gout scoring system showed longitudinal validity with both tophus and DC being highly responsive to treatment when assessed in static images/videos. A responsive US measure for urate deposition and a feasible joint/tendon set for monitoring were proposed and may prove valuable in future longitudinal studies.

OP0287 LONGITUDINAL ASSESSMENT OF THE ULTRASOUND GOUT LESIONS USING THE VALIDATED OMERACT SEMI-QUANTITATIVE SCORING SYSTEM

Background

In gout, ultrasound (US) is a promising tool to detect changes in monosodium urate (MSU) depositions during urate-lowering therapy (ULT). The OMERACT US group has developed definitions of gout-specific US lesions[1] and a semi-quantitative scoring system for US lesions representing MSU deposition (tophus, double contour (DC) and aggregates)[2], but the responsiveness of lesions when applying this scoring system has not yet been assessed.

Objectives

The primary aim was to evaluate the responsiveness of gout-specific US lesions in patients receiving treat-to-target ULT using both a binary (present/absent) and the OMERACT-defined semi-quantitative (0-3) scoring system. The secondary aims were to determine the most responsive US measure for MSU deposition at patient level and the optimal joint/tendon set for monitoring lesions.

Methods

US (28 joints, 14 tendons) was performed in microscopically verified gout patients initiating/increasing ULT and repeated after 6 and 12 months. Static images and videos of pathologies were stored. Tophus, DC and aggregates were scored binarily and semi-quantitatively. Individual lesion-scores were calculated at patient level as were combined crystal sum scores. Standardised response means (SRM) for lesions when scored binarily and semi-quantitatively were calculated at patient and joint/tendon level.

Results

Sixty-three patients were followed for 12 months. Plasma urate levels were effectively lowered during follow-up (Table 1). US showed statistically significant decreases in tophus and DC sum scores, both when scored binarily and semi-quantitatively, whereas aggregates were almost unchanged during follow-up (Table 1). SRMs for the semi-quantitative tophus and DC sum scores were markedly higher than those for the binary. The most responsive measure for urate deposition at patient level was a combined semi-quantitative tophus-DC-sum score (SRM 0.92, Table 1). A reduced joint/tendon set for monitoring included knee and 1st–2nd metatarsophalangeal joints and peroneus and distal patella tendons representing the most prevalent and responsive sites (SRM 1.13, Figure 1).

Table 1.

Course and SRMs of US scores during 12 months’ follow-up

Baseline6-months’ follow-up12-months’ follow-upP-value*SRMMeanMedian [IQR]MeanMedian [IQR]MeanMedian [IQR]Δ 0–6 monthsΔ 6–12 monthsΔ 0–12 months12 monthsP-urate (mmol/L)0.490.48 [0.42;0.56]0.330.32 [0.29; 0.36]0.310.30 [0.27;0.35]<0.0010.0464<0.001-SQ ultrasound scoring (0–3), [possible range]:DC sum score, [0–84]5.53 [1; 8]3.72 [0; 5]2.21 [0; 4]<0.001<0.001<0.0010.80Tophus sum score, [0–126]9.56 [4; 11]8.25 [3; 9]6.44 [2; 7]<0.001<0.001<0.0010.84Aggregates sum score, [0–126]12.210 [7; 16]12.610 [7; 16]11.811 [6; 15]0.8750.1920.5820.07SQ-TD-sum score, [0–210]15.010 [6; 16]11.98 [5; 12]8.76 [4; 9]<0.001<0.001<0.0010.92SQ-TDA-sum score, [0–336]27.222 [14; 30]24.618 [12; 28]20.516 [9; 25]<0.001<0.001<0.0010.73Binary ultrasound scoring (0–1), [possible range]:DC sum score, [0–28]1.81 [0; 3]1.11 [0; 2]0.60 [0; 1]<0.001<0.001<0.0010.72Tophus sum score, [0–42]3.42 [1; 4]3.02 [1; 3]2.32 [0; 3]0.002<0.001<0.0010.75Aggregates sum score, [0–42]4.43 [2; 6]4.74 [2; 6]4.24 [2; 6]0.3560.1250.7320.07Binary-TD-sum score, [0–70]5.33 [2; 6]4.23 [1; 4]2.92 [1; 3]<0.001<0.001<0.0010.86Binary-TDA-sum score, [0–112]9.78 [5; 11]8.87 [4; 10]7.16 [3; 9]<0.0010.001<0.0010.70

US, ultrasound; SQ, semi-quantitative; SRM, standardised response mean; DC, double contour; TD-sum score, tophus+DC sum score, TDA-sum score, tophus+DC+aggregates sum score. * Wilcoxon signed rank test, statistically significant results are indicated by bold-face type.

Conclusion

The OMERACT consensus-based semi-quantitative US gout scoring system showed longitudinal validity with both tophus and DC being highly responsive to treatment. A responsive US measure for urate deposition and a feasible joint/tendon set for monitoring are proposed.

References

[1]Gutierrez et al. 2015.

[2]Christiansen et al. 2021.

Acknowledgements

The Danish Rheumatism Association is acknowledged for financial support of the salary of SNC.

Disclosure of Interests

Sara Nysom Christiansen Speakers bureau: SNC has received speaker fees from BMS and GE, Grant/research support from: SNC has received funding from Novartis, Mikkel Østergaard Speakers bureau: MØ has received research support and/or consultancy/speaker fees from Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Centocor, GSK, Gilead, Galapagos, Hospira, Janssen, Merck, Mundipharma, Novartis, Novo, Orion, Pfizer, Regeneron, Schering-Plough, Roche, Takeda, UCB and Wyeth., Grant/research support from: MØ has received research support and/or consultancy/speaker fees from Abbvie, BMS, Boehringer-Ingelheim, Celgene, Eli-Lilly, Centocor, GSK, Gilead, Galapagos, Hospira, Janssen, Merck, Mundipharma, Novartis, Novo, Orion, Pfizer, Regeneron, Schering-Plough, Roche, Takeda, UCB and Wyeth., Ole Slot: None declared, Viktoria Fana: None declared, Lene Terslev Speakers bureau: LT has received speakers’ fees from AbbVie, MSD, Novartis, Roche, Pfizer, GE, BMS and Janssen.

Do tender joints in active psoriatic arthritis reflect inflammation assessed by ultrasound and magnetic resonance imaging?

OBJECTIVE

To investigate the association between clinical joint tenderness and intra- and periarticular inflammation as assessed by ultrasound and magnetic resonance imaging (MRI) in patients with active psoriatic arthritis (PsA) and to explore if the associations differ according to patient-reported outcomes (PROs) and structural damage.

METHODS

Forty-one patients with active PsA and hand involvement had 76/78 joints examined for swelling/tenderness and ultrasound and MRI of 24 and 12 finger joints, respectively. Synovitis, tenosynovitis, periarticular inflammation and erosions were assessed using OMERACT definitions and scoring systems. Correlation between imaging inflammation sum-scores (intra-and periarticular) and tender/swollen joint counts were calculated using Spearman's rho, agreement at joint level was examined using prevalence and bias adjusted kappa (PABAK). Subgroup analyses explored the influence of PROs and radiographic erosive disease on these associations.

RESULTS

No significant correlations were found between tender or swollen joint counts and imaging inflammation sum-scores (rho=-0.31-0.38). In patients with higher level of overall pain, disability and lower self-reported mental health, a tendency towards negative correlations were found. At joint level, intra- and periarticular imaging inflammatory lesions had slight agreement with joint tenderness (PABAK=0.02-0.19) and slight to moderate with swelling (PABAK=0.16-0.54). For tender joints, agreement with imaging inflammation was even weaker in patients with either high overall pain scores, high disability scores, and/or non-erosive disease.

CONCLUSION

Joint tenderness had low association with imaging signs of inflammation in PsA patients, particularly in patients with high self-reported pain, disability and low mental health, indicating that tenderness is influenced by other parameters than local inflammation.

Assessing the sensitivity to change of the OMERACT ultrasound structural gout lesions during urate-lowering therapy

Objectives

To evaluate the sensitivity to change of ultrasound structural gout lesions, as defined by the Outcome Measures in Rheumatology (OMERACT) ultrasound group, in patients with gout during urate-lowering therapy (ULT).

Methods

Ultrasound (28 joints, 26 tendons) was performed in patients with microscopically verified gout initiating or increasing ULT and repeated after 3 and 6 months. Joints and tendons were evaluated by ultrasound for presence of the OMERACT structural gout lesions—double contour sign (DC), tophus, aggregates and erosion—scored binarily. A sum score was calculated at patient and lesion level. Changes at 3 and 6 months in patient sum scores and lesion scores at different locations were evaluated.

Results

50 patients (48 men), mean age 68.9 (range, 30–88) years, were included. Ultrasound showed a statistically significant decrease in DC and tophus sum scores from 0 months (3.16 and 2.68, respectively) to 3 months (2.33 and 2.43) and 6 months (1.34 and 1.83) (all p<0.002). The aggregate sum score only decreased significantly from 3 to 6 months (6.02 to 5.02, p=0.002), whereas erosion sum score remained almost unchanged. All four structural lesions were most commonly found in metatarsophalangeal (MTP) 1 joints (>1 lesions bilaterally), and furthermore MTP2–4 and knee joints were common sites especially for DC. Likewise, these regions were the locations with most pronounced changes in scores.

Conclusion

Ultrasound assessment of the OMERACT structural gout lesions scored binarily seems to be a useful tool for monitoring urate depositions during ULT. Particularly DC and tophus showed sensitivity to change after only 3 months of treatment.

Ultrasound for the diagnosis of gout-the value of gout lesions as defined by the Outcome Measures in Rheumatology ultrasound group

OBJECTIVE

To evaluate ultrasound for diagnosing gout using consensus-based Outcome Measures in Rheumatology ultrasound definitions of gout lesions.

METHODS

Ultrasound was performed in patients with clinically suspected gout. Joints (28) and tendons (26) were binarily evaluated for the Outcome Measures in Rheumatology gout lesions-double contour (DC), tophus, aggregates and erosions. Ultrasound assessment was compared with two reference standards: (i) presence of MSU crystals in joint/tophus aspirate (primary outcome) and (ii) ACR/EULAR 2015 gout classification criteria (secondary outcome). Both reference standards were evaluated by rheumatologists blinded to ultrasound findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of each ultrasound lesion against both reference standards were determined.

RESULTS

Eighty-two patients (70 men), mean age 62.4 (range 19-88) years, were included. Fifty-seven patients were MSU-positive whereas 25 patients were MSU-negative (no MSU crystals: 23; aspiration unsuccessful: 2). Of these 25 patients, three patients were classified as ACR/EULAR-positive (i.e. totally 60 ACR/EULAR-positive patients). All ultrasound lesions had high sensitivities for gout (0.77-0.95). DC and tophus showed high specificities (0.88-0.95), positive predictive values (0.94-0.98) and accuracies (0.82-0.84) when both reference standards were used. In contrast, low specificities were found for aggregates and erosions (0.32-0.59). Ultrasound of MTP joints for DC or tophus, knee joint for DC and peroneus tendons for tophus was sufficient to identify all MSU-positive patients with ultrasound signs of gout at any location.

CONCLUSION

Ultrasound-visualized DC and tophus, as defined by the Outcome Measures in Rheumatology ultrasound group, show high specificities, positive predictive values and accuracies for diagnosing gout and are therefore valid tools in clinical practice.

Dual-energy CT in gout patients: Do all colour-coded lesions actually represent monosodium urate crystals?

BACKGROUND

Dual-energy CT (DECT) can acknowledge differences in tissue compositions and can colour-code tissues with specific features including monosodium urate (MSU) crystals. However, when evaluating gout patients, DECT frequently colour-codes material not truly representing MSU crystals and this might lead to misinterpretations. The characteristics of and variations in properties of colour-coded DECT lesions in gout patients have not yet been systematically investigated. The objective of this study was to evaluate the properties and locations of colour-coded DECT lesions in gout patients.

METHODS

DECT of the hands, knees and feet were performed in patients with suspected gout using factory default gout settings, and colour-coded DECT lesions were registered. For each lesion, properties [mean density (mean of Hounsfield Units (HU) at 80 kV and Sn150kV), mean DECT ratio and size] and location were determined. Subgroup analysis was performed post hoc evaluating differences in locations of lesions when divided into definite MSU depositions and possibly other lesions.

RESULTS

In total, 4033 lesions were registered in 27 patients (23 gout patients, 3918 lesions; 4 non-gout patients, 115 lesions). In gout patients, lesions had a median density of 160.6 HU and median size of 6 voxels, and DECT ratios showed an approximated normal distribution (mean 1.06, SD 0.10), but with a right heavy tail consistent with the presence of smaller amounts of high effective atomic number lesions (e.g. calcium-containing lesions). The most common locations of lesions were 1st metatarsophalangeal (MTP1), knee and midtarsal joints along with quadriceps and patella tendons. Subgroup analyses showed that definite MSU depositions (large volume, low DECT ratio, high density) had a similar distribution pattern, whereas possible calcium-containing material (high DECT ratio) and non-gout MSU-imitating lesions (properties as definite MSU depositions in non-gout patients) were primarily found in some larger joints (knee, midtarsal and talocrural) and tendons (Achilles and quadriceps). MTP1 joints and patella tendons showed only definite MSU depositions.

CONCLUSION

Colour-coded DECT lesions in gout patients showed heterogeneity in properties and distribution. MTP1 joints and patella tendons exclusively showed definite MSU depositions. Hence, a sole focus on these regions in the evaluation of gout patients may improve the specificity of DECT scans.

OP0177 PROPERTIES AND LOCATIONS OF COLOR-CODED DUAL ENERGY CT LESIONS IN GOUT PATIENTS – A SYSTEMATIC EVALUATION

Background:

Dual energy CT (DECT) has diagnostic potential in gout patients. DECT can automatically colour-code presumed urate deposits based on radiodensity (Hounsfield Units, HU) and DECT ratio (difference in attenuation between high and low kV series) of lesions. However, other materials may imitate properties of urate deposits, most importantly calcium-containing material, dense tendons and artefacts, which may lead to misinterpretations. The characteristics of DECT lesions in gout patients have not yet been systematically investigated.

Objectives:

To evaluate the properties and locations of colour-coded DECT lesions in gout patients.

Methods:

DECT were performed in patients with suspected gout. Patients were separated into gout and non-gout patients based on joint fluid microscopy findings. DECT of the hands, knees and feet were performed using default gout settings and colour-coded lesions were registered. Only location-relevant lesions were analysed (e.g. nail bed artefacts excluded). Mean density (mean of HU at 80 kV and Sn150 kV), mean DECT ratio, size and location of each lesion was determined.

Subgroup analysis was performed post-hoc evaluating potential differences in properties and locations of lesions. Lesions were separated into groups according to properties (Figure 1, grey box): 1)Size—to separate artefacts characterised by small volume (possible artefacts). 2)DECT ratios—to separate calcium-containing material characterised by high DECT ratio (possible calcium-containing material). 3)Density—to separate dense tendons characterised by low DECT ratio and low HU values (possible dense tendons). Lesion fulfilling all urate characteristics (large volume, low DECT ratio, high density) were labelleddefinite urate deposits. Finally, for non-gout patients, properties ofnon-gout urate-imitation lesions(properties asdefinite urate deposits) were analysed.

Results:

In total, 3918 lesions (all lesions) were registered in gout patients (n=23), with mean DECT ratio 1.06 (SD 0.13), median density 160.6 HU and median size 6 voxels (Figure 1, blue box). Lesions were seen in all analysed joints, most frequently MTP1 joints (medial side), knee joints and midtarsal joints (Figure 2a). Tendon affections were also common, especially in the knee tendons (patella and quadriceps), malleolus-related tendons (e.g. peroneus and tibialis posterior) and the Achilles tendons (Figure 2a).

Subgroup analyses showed thatdefinite urate deposits(figure 2b) were found at the same locations asall lesionin gout patients (figure 2a), with the four most common sites being MTP1 joints, midtarsal joints, and quadriceps and patella tendons (Figure 2b).Possible dense tendonlesions had a mean HU value of 156.5 HU—markedly higher than expected for dense tendons (<100HU)—and lesion-locations were similar todefinite urate deposits(data not shown), indicating that they primarily consisted of true urate deposits. In contrast,possible calcium-containing materialandnon-gout urate-imitating lesionshad distinctly different properties (ratios 1.33 and 1.20, respectively) (Figure 1, yellow and orange box). Furthermore, the locations of these lesions were different fromdefinite urate depositssince they were primarily found in a few weight-bearing joints (knee, midtarsal and talocrural including malleolus regions) and tendons (Achilles and quadriceps), whereas no lesions were found in either MTP1 joints or patella tendons (figure 2c).

Conclusion:

DECT color-coded lesions in gout patients are heterogeneous in properties and locations. Subgroup analyses found that locations such as MTP1 joints and patella tendons were characterised by almost only showingdefinite urate deposits. A sole focus on these regions in the evaluation of gout patients may therefore improve specificity of DECT scans.

Disclosure of Interests:

Sara Nysom Christiansen Speakers bureau: SNC has received speaker fees from Bristol Myers Squibb (BMS) and General Electric (GE)., Felix C Müller Employee of: Siemens Healthineers., Mikkel Ǿstergaard Grant/research support from: AbbVie, Bristol-Myers Squibb, Celgene, Merck, and Novartis, Consultant of: AbbVie, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo Nordisk, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Speakers bureau: AbbVie, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Eli Lilly, Hospira, Janssen, Merck, Novartis, Novo Nordisk, Orion, Pfizer, Regeneron, Roche, Sandoz, Sanofi, and UCB, Ole Slot: None declared, Jakob Møllenbach Møller: None declared, Henrik F Børgesen: None declared, Kasper K Gosvig: None declared, Lene Terslev Speakers bureau: LT declares speakers fees from Roche, MSD, BMS, Pfizer, AbbVie, Novartis, and Janssen.

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.

Specificity of Anti-Citrullinated Protein Antibodies in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology. The majority of individuals with RA are positive for the disease-specific anti-citrullinated protein antibodies (ACPAs). These antibodies are primarily of cross-reactive nature, hence, the true autoantigen to ACPA remains unidentified. In this study, we analyzed the reactivity of RA sera to several post-translationally modified epitopes, in order to further characterize the specific nature of ACPAs by immunoassays. Substituting citrulline with other amino acids, e.g., D-citrulline, homo-citrulline and methyl-arginine illustrated that ACPAs are utmost specific for citrullinated targets. Collectively, these findings support that ACPAs and citrullinated targets are specific for RA, making citrulline-containing peptide targets the most effective assays for detection of ACPAs.

Antibodies to a strain-specific citrullinated Epstein-Barr virus peptide diagnoses rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease. Anti-citrullinated protein antibodies (ACPA) are crucial for the serological diagnosis of RA, where Epstein-Barr virus (EBV) has been suggested to be an environmental agent in triggering the onset of the disease. This study aimed to analyse antibody reactivity to citrullinated EBV nuclear antigen-2 (EBNA-2) peptides from three different EBV strains (B95-8, GD1 and AG876) using streptavidin capture enzyme-linked immunosorbent assay. One peptide, only found in a single strain (AG876), obtained a sensitivity and specificity of 77% and 95%, respectively and showed high sequence similarity to the filaggrin peptide originally used for ACPA detection. Comparison of antibody reactivity to commercial assays found that the citrullinated peptide was as effective in detecting ACPA as highly sensitive and specific commercial assays. The data presented demonstrate that the citrullinated EBNA-2 peptide indeed is recognised specifically by RA sera and that the single peptide is able to compete with assays containing multiple peptides. Furthermore, it could be hypothesized that RA may be caused by (a) specific strain(s) of EBV.

Development of Preliminary Remission Criteria for Gout Using Delphi and 1000Minds Consensus Exercises

OBJECTIVE

To establish consensus for potential remission criteria to use in clinical trials of gout.

METHODS

Experts (n = 88) in gout from multiple countries were invited to participate in a web-based questionnaire study. Three rounds of Delphi consensus exercises were conducted using SurveyMonkey, followed by a discrete-choice experiment using 1000Minds software. The exercises focused on identifying domains, definitions for each domain, and the timeframe over which remission should be defined.

RESULTS

There were 49 respondents (56% response) to the initial survey, with subsequent response rates ranging from 57% to 90%. Consensus was reached for the inclusion of serum urate (98% agreement), flares (96%), tophi (92%), pain (83%), and patient global assessment of disease activity (93%) as measurement domains in remission criteria. Consensus was also reached for domain definitions, including serum urate (<0.36 mm), pain (<2 on a 10-point scale), and patient global assessment (<2 on a 10-point scale), all of which should be measured at least twice over a set time interval. Consensus was not achieved in the Delphi exercise for the timeframe for remission, with equal responses for 6 months (51%) and 1 year (49%). In the discrete-choice experiment, there was a preference towards 12 months as a timeframe for remission.

CONCLUSION

These consensus exercises have identified domains and provisional definitions for gout remission criteria. Based on the results of these exercises, preliminary remission criteria are proposed with domains of serum urate, acute flares, tophus, pain, and patient global assessment. These preliminary criteria now require testing in clinical data sets.

Performance of Ultrasound in the Diagnosis of Gout in a Multicenter Study: Comparison With Monosodium Urate Monohydrate Crystal Analysis as the Gold Standard

OBJECTIVE

To examine the performance of ultrasound (US) for the diagnosis of gout using the presence of monosodium urate monohydrate (MSU) crystals as the gold standard.

METHODS

We analyzed data from the Study for Updated Gout Classification Criteria (SUGAR), a large, multicenter observational cross-sectional study of consecutive subjects with at least 1 swollen joint who conceivably may have gout. All subjects underwent arthrocentesis; cases were subjects with confirmed MSU crystals. Rheumatologists or radiologists who were blinded with regard to the results of the MSU crystal analysis performed US on 1 or more clinically affected joints. US findings of interest were double contour sign, tophus, and snowstorm appearance. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Multivariable logistic regression models were used to examine factors associated with positive US results among subjects with gout.

RESULTS

US was performed in 824 subjects (416 cases and 408 controls). The sensitivity, specificity, PPV, and NPV for the presence of any 1 of the features were 76.9%, 84.3%, 83.3%, and 78.2%, respectively. Sensitivity was higher among subjects with a disease duration of ≥2 years and among subjects with subcutaneous nodules on examination (suspected tophus). Associations with a positive US finding included suspected clinical tophus (odds ratio [OR] 4.77 [95% confidence interval (95% CI) 2.23-10.21]), any abnormality on plain radiography (OR 4.68 [95% CI 2.68-8.17]), and serum urate level (OR 1.31 [95% CI 1.06-1.62]).

CONCLUSION

US features of MSU crystal deposition had high specificity and high PPV but more limited sensitivity for early gout. The specificity remained high in subjects with early disease and without clinical signs of tophi.

Physical Characteristics of a Citrullinated Pro-Filaggrin Epitope Recognized by Anti-Citrullinated Protein Antibodies in Rheumatoid Arthritis Sera

Rheumatoid arthritis (RA) is an autoimmune disease of complex etiology. A characteristic feature of a subset of RA is the presence of anti-citrullinated protein antibodies (ACPA), which correlate with a progressive disease course. In this study, we employed streptavidin capture enzyme-linked immunosorbent assay to analyze ACPA reactivity. Using the pro-filaggrin peptide HQCHQEST-Cit-GRSRGRCGRSGS, as template, we analyzed the reactivity of RA sera and healthy donor sera to various peptides in order to determine the physical characteristics of the citrullinated pro-filaggrin epitope and to examine whether biotin labelling influence antibody recognition. The full-length cyclic pro-filaggrin peptide and a linear form with a N-terminal biotin, was recognized to the same level, whereas, a notable difference in ACPA reactivity to the linear peptides with a C-terminal biotin was found, probably due to steric hindrance. Screening of linear and cyclic truncated peptides, revealed that small cyclic peptides containing 10–12 amino acids are favored over the linear. Moreover, the charged amino acids C-terminal to citrulline were found to be essential for antibody reactivity, most important was the charged amino acid in position 4 C-terminal to citrulline. Collectively, peptide structure, length, the presence of charged amino acids and biotin labelling markedly influence antibody reactivity. In relation to the clinical diagnostics of ACPA, these findings may reflect the differences in diagnostic assays used for detection of ACPA, which relates to differences in sensitivity and specificity dependent on the assay applied.

Hand bone loss in early rheumatoid arthritis during a methotrexate-based treat-to-target strategy with or without adalimumab-a substudy of the optimized treatment algorithm in early RA (OPERA) trial

This study aims to investigate 1-year hand bone loss (HBL_1-year) in early rheumatoid arthritis (RA) patients treated with a methotrexate (MTX) and intra-articular triamcinolone treat-to-target strategy +/- adalimumab and to determine if HBL_6months is associated with radiographic progression after 2 years. In a clinical trial (OPERA) of 180 treatment-naive early RA patients, bone mineral density (BMD) was estimated from hand radiographs with digital X-ray radiogrammetry (DXR) at baseline, after 6 (n = 90) and 12 months (n = 70) of follow-up. Baseline and 2-year radiographs were scored according to the Sharp/van der Heijde method. Baseline characteristics and HBL_6months (0-6 months changes in DXR-BMD) were investigated as predictors of structural damage by univariate linear (∆ total Sharp/van der Heijde score (TSS) as dependent variable) and logistic (+/-radiographic progression (∆TSS >0) as dependent variable) regression analyses. Variables with p < 0.10 were included in multivariable models. In 70 patients with available HBL_1-year data, HBL_1-year was median (interquartile range (IQR)) -1.9 (-3.3; -0.26 mg/cm²) in the MTX + placebo group and -1.8 (-3.6; 0.06) mg/cm² in the MTX + adalimumab group, p = 0.98, Wilcoxon signed-rank. Increased HBL (compared to general population reference values) was found in 26/37 and 23/33 patients in the MTX + placebo and MTX + adalimumab groups, chi-squared = 0.99. In 90 patients with HBL_6months data and 2-year radiographic data, HBL_6months was independently associated with ∆TSS after 2 years (β = -0.086 (95% confidence interval = -0.15; -0.025) TSS unit/mg/cm² increase, p = 0.006) but not with presence of radiographic progression (∆TSS >0) (OR 0.96 (0.92-1.0), p = 0.10). In early RA patients treated with a methotrexate-based treat-to-target strategy, the majority of patients had increased HBL_1-year, irrespective of adalimumab; HBL_6months was independently associated with ∆TSS after 2 years.

Study for Updated Gout Classification Criteria: Identification of Features to Classify Gout

OBJECTIVE

To determine which clinical, laboratory, and imaging features most accurately distinguished gout from non-gout.

METHODS

We performed a cross-sectional study of consecutive rheumatology clinic patients with ≥1 swollen joint or subcutaneous tophus. Gout was defined by synovial fluid or tophus aspirate microscopy by certified examiners in all patients. The sample was randomly divided into a model development (two-thirds) and test sample (one-third). Univariate and multivariate association between clinical features and monosodium urate-defined gout was determined using logistic regression modeling. Shrinkage of regression weights was performed to prevent overfitting of the final model. Latent class analysis was conducted to identify patterns of joint involvement.

RESULTS

In total, 983 patients were included. Gout was present in 509 (52%). In the development sample (n = 653), the following features were selected for the final model: joint erythema (multivariate odds ratio [OR] 2.13), difficulty walking (multivariate OR 7.34), time to maximal pain <24 hours (multivariate OR 1.32), resolution by 2 weeks (multivariate OR 3.58), tophus (multivariate OR 7.29), first metatarsophalangeal (MTP1) joint ever involved (multivariate OR 2.30), location of currently tender joints in other foot/ankle (multivariate OR 2.28) or MTP1 joint (multivariate OR 2.82), serum urate level >6 mg/dl (0.36 mmoles/liter; multivariate OR 3.35), ultrasound double contour sign (multivariate OR 7.23), and radiograph erosion or cyst (multivariate OR 2.49). The final model performed adequately in the test set, with no evidence of misfit, high discrimination, and predictive ability. MTP1 joint involvement was the most common joint pattern (39.4%) in gout cases.

CONCLUSION

Ten key discriminating features have been identified for further evaluation for new gout classification criteria. Ultrasound findings and degree of uricemia add discriminating value, and will significantly contribute to more accurate classification criteria.

Application of synthetic peptides for detection of anti-citrullinated peptide antibodies

Anti-citrullinated protein antibodies (ACPAs) are a hallmark of rheumatoid arthritis (RA) and represent an important tool for the serological diagnosis of RA. In this study, we describe ACPA reactivity to overlapping citrullinated Epstein-Barr virus nuclear antigen-1 (EBNA-1)-derived peptides and analyze their potential as substrates for ACPA detection by streptavidin capture enzyme-linked immunosorbent assay. Using systematically overlapping peptides, containing a 10 amino acid overlap, labelled with biotin C-terminally or N-terminally, sera from 160 individuals (RA sera (n=60), healthy controls (n=40), systemic lupus erythematosus (n=20), Sjögren's syndrome (n=40)) were screened for antibody reactivity. Antibodies to a panel of five citrullinated EBNA-1 peptides were found in 67% of RA sera, exclusively of the IgG isotype, while 53% of the patient sera reacted with a single peptide, ARGGSRERARGRGRG-Cit-GEKR, accounting for more than half of the ACPA reactivity alone. Moreover, these antibodies were detected in 10% of CCP2-negative RA sera. In addition, 47% of the RA sera reacted with two or three citrullinated EBNA-1 peptides from the selected peptide panel. Furthermore, a negative correlation between the biotin attachment site and the location of citrulline in the peptides was found, i.e. the closer the citrulline was located to biotin, the lower the antibody reactivity. Our data suggest that citrullinated EBNA-1 peptides may be considered a substrate for the detection of ACPAs and that the presence of Epstein-Barr virus may play a role in the induction of these autoantibodies.

Diagnostic Arthrocentesis for Suspicion of Gout Is Safe and Well Tolerated

OBJECTIVE

To determine the frequency of adverse events of diagnostic arthrocentesis in patients with possible gout.

METHODS

Consecutive patients underwent arthrocentesis and were evaluated at 6 weeks to determine adverse events. The 95% CI were obtained by bootstrapping.

RESULTS

Arthrocentesis was performed in 910 patients, and 887 (97.5%) were evaluated for adverse events. Any adverse event was observed in 12 participants (1.4%, 95% CI 0.6-2.1). There was 1 case (0.1%, 95% CI 0-0.34) of septic arthritis.

CONCLUSIONS

Diagnostic arthrocentesis is associated with a low frequency of adverse events. Septic arthritis rarely occurs.

Performance of classification criteria for gout in early and established disease

OBJECTIVES

To compare the sensitivity and specificity of different classification criteria for gout in early and established disease.

METHODS

This was a cross-sectional study of consecutive rheumatology clinic patients with joint swelling in which gout was defined by presence or absence of monosodium urate crystals as observed by a certified examiner at presentation. Early disease was defined as patient-reported onset of symptoms of 2 years or less.

RESULTS

Data from 983 patients were collected and gout was present in 509 (52%). Early disease was present in 144 gout cases and 228 non-cases. Sensitivity across criteria was better in established disease (95.3% vs 84.1%, p<0.001) and specificity was better in early disease (79.9% vs 52.5%, p<0.001). The overall best performing clinical criteria were the Rome criteria with sensitivity/specificity in early and established disease of 60.3%/84.4% and 86.4%/63.6%. Criteria not requiring synovial fluid analysis had sensitivity and specificity of less than 80% in early and established disease.

CONCLUSIONS

Existing classification criteria for gout have sensitivity of over 80% in early and established disease but currently available criteria that do not require synovial fluid analysis have inadequate specificity especially later in the disease. Classification criteria for gout with better specificity are required, although the findings should be cautiously applied to non-rheumatology clinic populations.

Changes in plasma homocysteine in arthritis patients starting treatment with low-dose methotrexate subsequently supplemented with folic acid

In 15 patients with rheumatoid arthritis (RA) (n = 13) or psoriatic arthritis (PsA) (n = 2) p-homocystcine and erythrocyte folate (erc-FA) were measured before start of methotrexate (MTX) treatment, after 4 weeks of MTX treatment (median 10 mg per week), and after further 4 weeks of treatment with MTX (median 12.5 mg per week) supplemented with folic acid (FA) (15 mg per week). Mean p-homocysteine were 12.3 +/- 3.4 micromol/l, 14.6+/-5.8 micromol/l (p<0.05) and 10.3+/-3.0 micromol/l (p<0.01) respectively. P-homocysteine concentrations were negative correlated to erc-FA after 4 weeks (rho -0.58; p<0.05). It is concluded that treatment with MTX induces a significant rise in p-homocysteine that is neutralised by FA supplementation. Supplementation with FA from the start of MTX treatment is recommended considering the increased risk of cardiovascular disease that is associated with elevated concentrations of p-homocysteine.

Arthritis as presenting symptom in silent adult coeliac disease. Two cases and review of the literature

We report 2 cases of adult silent coeliac disease (CD) presenting with arthritis of a knee and a sacro-iliac joint, respectively. In both patients the arthritis was relieved on a gluten free diet. The literature on arthritis in adult CD is reviewed.

A prospective study of vasculitis patients collected in a five year period: evaluation of the Chapel Hill nomenclature

OBJECTIVE

To test the usefulness of the Chapel Hill nomenclature, supplemented with surrogate parameters, as diagnostic criteria for primary vasculitides.

METHODS

To prospectively evaluate vasculitis patients according to a standardised clinical and para-clinical programme. In accordance with the Chapel Hill publication surrogate parameters were used: proteinuria, haematuria and red blood cell casts (glomerulonephritis), angiographic or ultrasonic demonstration of aneurysms or stenoses (arteritis), radiological lung infiltrates or cavitations of more than one month's duration (granuloma in the lungs), bloody nasal discharge or crusts, chronic sinusitis, otitis and/or mastoiditis, bone and/or cartilage destruction, and acute hearing loss (granuloma in upper airways).

RESULTS

The following entities were diagnosed: giant cell arteritis (n=14), Takayasu arteritis (n=1), polyarteritis nodosa (n=2), Wegener's granulomatosis (n=27), Churg-Strauss syndrome (n=2), microscopic polyangiitis (n=12), Henoch-Schönlein purpura (n=2), cutaneous leucocytoclastic angiitis (n=37), and secondary vasculitis (n=21). Giant cell arteritis and cutaneous leucocytoclastic angiitis were in all cases diagnosed by biopsy. Using the Chapel Hill nomenclature supplemented with surrogate parameters, only 8 of 27 patients were diagnosed with Wegener's granulomatosis, and 3 of 12 cases with microscopic polyangiitis. The number of patients in the remaining diagnostic entities were considered to few to evaluate.

CONCLUSIONS

The Chapel Hill nomenclature, supplemented with surrogate parameters, failed to act as diagnostic criteria in Wegener's granulomatosis and microscopic polyangiitis. The following diagnostic criteria are proposed for Wegener's granulomatosis: (1) Biopsy or surrogate parameter for granulomatous inflammation in the respiratory system and (2) Biopsy verified necrotising vasculitis in small to medium sized vessels or biopsy/surrogate parameter for glomerulonephritis or positive PR3-ANCA test and (3) Lack of eosinophilia in blood and biopsy samples. The following diagnostic criteria are proposed for microscopic polyangiitis: (1) Biopsy verified necrotising vasculitis in small vessels and/or glomerulonephritis with few or no immune deposits and (2) Involvement of more than one organ system as indicated by biopsy verified vasculitis in small to medium sized vessels or surrogate parameter for glomerulonephritis and (3) Lack of biopsy and surrogate parameter for granulomatous inflammation in the respiratory system. Using these criteria all Wegener's patients and 9 of 12 patients with microscopic polyangiitis could be diagnosed.

Soluble urokinase plasminogen activator receptor in plasma of patients with inflammatory rheumatic disorders: increased concentrations in rheumatoid arthritis

OBJECTIVE

Urokinase type plasminogen activator (uPA) catalyses the formation of the proteolytic enzyme plasmin, which is involved in matrix degradation in the processes of tissue remodelling. Because of a surface bound uPA receptor (uPAR), expressed by some cell types (for example, macrophages, malignant cells and inflammatory activated synoviocytes), the action of uPA can be localised and intensified. uPAR seems to have a role in the mechanisms leading to invasive growth of malignant tissue and the rheumatoid pannus. uPAR may become cleaved at its cell surface anchor, thus forming a free soluble receptor (suPAR). suPAR is detectable in low but constant values in plasma of healthy people, while increased concentrations are found in patients with disseminated malignant disease, so that suPAR may be an indicator of invasive growth and tissue remodelling. suPAR concentrations in plasma have not previously been measured in rheumatic patients. A controlled cross sectional measurement was performed of suPAR in plasma of patients with various inflammatory rheumatic disorders with special reference to rheumatoid arthritis (RA).

METHODS

suPAR in plasma was measured by ELISA technique in patients with RA (n=51), reactive arthritis (ReA) (n=23), primary Sjögren's syndrome (PSS) (n=42) and sex and age matched healthy controls (n=53).

RESULTS

In the control group suPAR (median) was 0. 91 (range 0.56-1.94) microg/l. Median suPAR value in RA was 1.47 (range 0.65-6.62) microgram/l; in ReA 0.68 microgram/l (range 0.52-1.48) and in PSS 1.12 microgram/l (range 0.76-1.92); p versus controls <0.001 in all patient groups. suPAR values in RA were also significantly increased compared with ReA (p<0.001) and PSS (p=0.004) groups. suPAR in RA was positively correlated to C reactive protein (CRP) (p<0.01) and erythrocyte sedimentation rate (p<0.05) and number of swollen joints (p<0.05). The ReA group had the highest CRP values of all groups, but at the same time the lowest suPAR concentrations in plasma.

CONCLUSIONS

Increased suPAR concentrations were found in plasma in RA, and to a smaller extent also in PSS, but not in ReA. In RA suPAR is related to disease activity. suPAR seems though not merely to be an acute phase reactant like CRP. Increased suPAR values might reflect erosive activity in RA.

[Epidural glucocorticoid injection in lumbago sciatica]

Within the past decades, epidural steroid injections have been used in the treatment of severe low back pain and sciatica. In reviewing papers for this article an effort is made to concentrate on those that meet commonly accepted research design criteria, such as being blinded, randomized and prospective. The risks and the advantages of the procedure are discussed. Some of the studies report an efficient reduction in low back pain and sciatica for a longer period. Risks of more serious complications are low using the right technique. However, the results are to some extent conflicting. Future correctly designed studies are necessary to clarify whether the injection should be a supplement to the established treatment of low back pain and sciatica.

[Gouty arthritis in women. The clinical picture in 13 newly diagnosed cases]

The clinical characteristics and symptoms at the time of diagnosis in 13 women with crystal-proven gouty arthritis were reviewed in a retrospective study based on hospital records. Twelve patients were at the age of 60 or older (median 74 years). Tophaceous gout occurred in four, oligo- or polyarticular involvement in seven. Six patients had actual symptoms for two months or more, only one of these seemed to have had previous acute gouty attacks. The arthritis occurred evenly in the upper and lower extremities. Ten (77%) were in diuretic treatment, 12 (92%) had diseases associated with hyperuricaemia. Only nine (69%) had serum urate concentrations over the upper limit of normal range (0.35 mmol/l).

[Hyperuricemia]

Uric acid is formed by catabolism of purine nucleotides. Approximately 25% is excreted through the intestines and the rest through the kidneys. A little less than 5% of the population in western industrialised countries have hyperuricaemia, primarily men and postmenopausal women. Hyperuricaemia is in most cases caused by reduced renal excretion, which may be idiopathic with otherwise normal renal function. But the condition is often associated with hypertension, nephropathy and treatment with diuretics and certain other drugs. Hyperuricaemia due to increased purine metabolism is seen in malignant haematological diseases, other conditions with increased cellular turnover and during initiation of chemotherapy in malignant diseases. Moreover hyperuricaemia is associated with some metabolic disturbances and risk factors of atherosclerotic cardiovascular disease including hypertension, overweight, insulin resistance and hyperlipidaemia. Hyperuricaemia is rarely caused by constitutional enzymatic abnormalities influencing purine metabolism. In most cases hyperuricaemia is asymptomatic. It may though be complicated by gout, urolithiasis and possibly gouty nephropathy. The risk of complications is correlated to the degree and duration of hyperuricemia. Consequently, measures to affect predisposing and associated conditions should be taken including weight reduction, physical exercise and diet guidance, treatment of hypertension and possibly changes in medication. Urate lowering drug treatment is normally not indicated in asymptomatic hyperuricaemic individuals.

[Arthritis urica. Clinical picture, diagnosis and treatment]

Gout is an acute episodic monarthritis or chronic pauci- or polyarticular arthritis. The symptoms of gout are induced by monosodium-urate crystals that are liberated from accumulations in connective tissue structures, primarily cartilage. Deposition of monosodium-urate crystals is caused by hyperuricaemia, which is dealt with in a previous paper. Only a minority of persons with hyperuricaemia develop gout, however. The diagnosis is based on detection of urate crystals in synovial fluid or tophi. Acute gout is treated with antiinflammatory agents, primarily NSAIDs or colchicine. Predisposing diseases and associated conditions such as hypertension, diuretic drugs, overweight and nephropathy should be controlled as well as possible. In patients with recurrent attacks of acute gout or chronic gout, treatment with urate lowering drugs, principally allopurinol, should be given. Treatment with allopurinol should be adjusted according to levels of serum urate and renal function. Serious complications to allopurinol treatment have been described.

[The disease course in patients admitted to a rehabilitation department following spinal cord injuries]

Epidemiologic data from 109 patients admitted to hospital in the period 1/1/1980-/31/12/1984 with spinal cord injuries are presented. The mean age was 29 years, there was a preponderance of males and the most frequent cause of the spinal cord injury was road accidents. The material was compared with the epidemiologic and social data of other studies. A total of 58 patients, chiefly users of wheelchairs, were followed up on average six years after the first admission. It was thus possible to form an idea of the complications of the spinal cord injury and the effectiveness of the treatment. The premorbid educational level of the patients was relatively low. The most frequent complications were spasms (74%), pressure sores (67%), pains (58%), and frequent urinary tract infections (71%). The consumption of medicine reflected the pattern of complications. The most common method of micturition was reflex voiding by tapping. These results were comparable with previous studies. It is concluded that the treatment of spinal cord injuries is a specialised task and only continuous evaluation can ensure optimum treatment.

Rehabilitation outcome for patients with spinal cord injury

A follow-up study of 58 patients with spinal cord injury was conducted. As measure of function the Barthel index was used. There was correlation between functional capacity and ability of self-care as well as some social determinants. However, no association was found with employment rate or certain other determinants of independent living, such as going on a holiday. We conclude that the severity of the lesion is a fundamental factor in determining the outcome, but factors related to personal and psychosocial variables, not easily measured, also have great influence on the rehabilitation process.

Erectile and ejaculatory function of males with spinal cord injury

The object of the study was to investigate the frequency of physiological sexual dysfunction in a population of men with spinal cord injury (SCI). A questionnaire-based survey of admissions during 1980-84 was undertaken at a regional spinal cord injury rehabilitation unit. Male patients aged 20-63 years with complete or incomplete tetraplegia or paraplegia living in their own homes were included in the study; 43 complied with inclusion criteria, and 38 answered the questionnaire. Ninety-five per cent of the patients stated that they could obtain an erection, 61% on a purely reflex basis; 66% stated that erection was sufficient for coitus, and 45% that they could obtain ejaculation/emission. More patients with incomplete than complete lesions reported ability to obtain ejaculation/emission. Significantly, more of the patients aged below 30 years reported erection sufficient for coitus (p less than 0.05). Forty-five per cent of the patients experienced complications of sexual activity, mainly in the form of bladder dysfunction and pain or spasms. In conclusion, SCI is usually accompanied by considerable sexual dysfunction, but most patients are still capable of functioning sexually. Thus, in the rehabilitation process after SCI, sexual counselling and information may be valuable.

The fibrinolytic system during short-term treatment with tenoxicam

The effect of 20 mg tenoxicam once daily for 7 days on various components of the fibrinolytic system was studied in 10 healthy volunteers. Plasma plasminogen, antithrombin 3, and prekallikrein decreased significantly while plasma plasminogen activator inhibitor increased significantly. The medication did not affect fibrin plate lysis area or the plasma level of plasminogen activator, alpha-2-antiplasmin, alpha-2-macroglobulin, C1 inactivator or Factor XII. It is suggested that these changes may be caused by interference with hepatic enzyme systems. The reduction in plasma prekallikrein may indicate that tenoxicam exerts its anti-inflammatory effect by more than one mechanism.