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Objectives: The effect of coffee on serum uric acid (SUA) has shown conflicting results. This study was to determine the effects of caffeinated coffee (CC) and decaffeinated coffee (DC) on SUA, serum xanthine oxidase activity (sXOA) and urine uric acid clearance (UAC)., Methods: This was a prospective randomised within-subject experimental study design of 51 healthy male participants. Each study period consisted of 3 periods, including a control, an intervention, and washout period for 1, 3 and 1 week, respectively. During the intervention period, the participants received 2, 4 or 6 gram/day of coffee, either CC or DC., Results: For DC groups, SUA significantly decreased by 6.5 (±1.1) mg/dL to 6.2 (±1.1) mg/dL during the intervention period (p=0.014). sXOA significantly increased by 0.05 (±0.07) nmol/min/mL to 0.20 (±0.38) nmol/min/mL during the intervention period (p=0.010) of CC. For UAC, there was no significant change with CC or DC. In hyperuricaemic participants, SUA significantly decreased by 7.7 (±0.7) mg/dL to 7.2 (±0.7) mg/dL during the intervention period (p=0.028) of DC. For non-hyperuricaemic, CC significantly increased SUA by 5.9 (±0.7) mg/dL to 6.2 (±0.9) mg/dL during the intervention period (p=0.008) and significantly decreased SUA to 6.0 (±0.8) mg/dL (p=0.049) during the withdrawal period. A significant increase of sXOA according with SUA in CC groups from 0.05 (±0.07) nmol/min/mL to 0.25 (±0.44) nmol/min/mL during the intervention period (p=0.040) was presented in non-hyperuricaemic participants., Conclusions: DC had a significant decrease of SUA during the intervention period. However, in non-HUS participants, SUA significantly increased in CC.

To evaluate the sensitivity and specificity of the 2015 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) gout classification criteria in Thai patients presenting with acute arthritis in a real-life setting. Data were analyzed on consecutive patients presenting with arthritis of less than 2 weeks duration. Sensitivity and specificity were calculated by using the presence of monosodium urate (MSU) crystals in the synovial fluid or tissue aspirate as gold standard for gout diagnosis. Subgroup analysis was performed in patients with early disease (≤2 years), established disease (>2 years), and those without tophus. Additional analysis also was performed in non-tophaceous gout patients, and patients with acute calcium pyrophosphate dihydrate crystal arthritis were used as controls. One hundred and nine gout and 74 non-gout patients participated in this study. Full ACR/EULAR classification criteria had sensitivity and specificity of 90.2 and 90.0%, respectively; and 90.2 and 85.0%, respectively, when synovial fluid microscopy was excluded. Clinical-only criteria yielded sensitivity and specificity of 79.8 and 87.8%, respectively. The criteria performed well among patients with early and non-tophaceous disease, but had lower specificity in patients with established disease. The variation of serum uric acid level was a major limitation of the classification criteria. The ACR/EULAR classification criteria had high sensitivity and specificity in Thai patients presenting with acute arthritis, even when clinical criteria alone were used.

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., Competing Interests: AO has received consulting fees from Novartis. ND has received consulting fees, speaker fees or grants from the following companies: Takeda, Menarini, Teijin, Pfizer, Crealta, Cymabay, Fonterra, Ardea Biosciences and AstraZeneca, outside the submitted work. WT has received consulting fees from AstraZeneca and Pfizer. FPR has received consulting fees from AstraZeneca, Menarini and Cymabay; speaker fees from AstraZeneca and Menarini; investigation grants from Spanish Health Ministry, Basque Country Industry and Development Department, Spanish Foundation for Rheumatology, and Cruces Hospital Rheumatology Association. LKS has received consulting fees from AstraZeneca. AKT has received fees from Berlin-Chemie Menarini, Andrea Biosciences/AstraZeneca and Novartis. GM has received consulting and speaker fees from Menarini. MAC has received investigation grants and speakers fees from Menarini., (© 2016, American College of Rheumatology.)

Objectives: The aim of this study was to determine the effect of antituberculous drugs on serum uric acid (SUA), urine uric acid (UUA) excretion, and renal function., Methods: Patients with tuberculosis requiring a 6-month treatment course of antituberculous drugs (isoniazid, rifampicin, pyrazinamide, and ethambutol for 2 months, followed by isoniazid and rifampicin for a further 4 months) were included in this study. Serum uric acid, 24-hour UUA excretion, uric acid clearance (UACl), serum creatinine, and creatinine clearance were determined at baseline and at the end of the second week, second month, and fourth month., Results: Sixteen of 50 patients completed the study. Their mean ± SD baseline SUA and UACl was 4.44 ± 1.72 mg/dL and 8.77 ± 7.03 mL/min per 1.73 m, respectively. At the second week, a significant increase in SUA (9.78 ± 3.21 mg/dL, P < 0.001) and significant decrease in UACl (3.50 ± 2.50 mL/min per 1.73 m, P = 0.001) were noted. These changes persisted through the second month, but returned to baseline value at the fourth month. Thirteen patients (81.25%) had hyperuricemia. The 24-hour UUA followed the same pattern as that of UACl but showed no statistical significance. There were no changes in serum creatinine or creatinine clearance. One patient had arthralgia, and another developed tuberculous arthritis., Conclusions: The hyperuricemic effect of pyrazinamide and ethambutol was due primarily to a decrease in UACl, which was reversible, and had no negative effect on the renal function. Arthralgia was uncommon and required no specific treatment.

Objective: The objective of this study was to investigate the hypouricemic effects of green tea extract (GTE) in healthy individuals., Methods: This study comprised 1-week control, 2-week interventional, and 1-week follow-up periods. Participants were assigned randomly at the interventional period to consume GTE at 2 (GTE2), 4 (GTE4), or 6 (GTE6) g/d. Levels of serum uric acid (SUA), uric acid clearance, and serum antioxidant power (using trolox equivalent antioxidant capacity assay) were measured at both ends of each study period., Results: Of 30 participants, 11, 11, and 8 received GTE2, GTE4, and GTE6, respectively. After 2 weeks of consumption, the mean SUA level tended to decrease in all groups, with no statistical significance. Serum uric acid reduction was greatest in GTE2 (from 4.81 ± 0.81 mg/dL to 4.64 ± 0.92 mg/dL, 3.53%). Uric acid clearance decreased significantly in GTE2 (from 11.37 ± 6.41 mL/min per 1.73 m to 7.44 ± 2.74 mL/min per 1.73 m, 34.56%, P < 0.05) and GTE4 (from 8.36 ± 3.41 mL/min per 1.73 m to 5.78 ± 2.33 mL/min per 1.73 m, 30.86%, P < 0.05). Serum antioxidant capacity (TEAC) increased significantly in GTE6 (from 32.77 ± 3.39 mg/mL to 35.41 ± 3.17 mg/mL, 8.06%, P < 0.05). There was no significant change in creatinine clearance. Gastrointestinal adverse events were common, but usually mild, with no medical treatment required., Conclusions: Green tea extract may modestly lower SUA level and decreases uric acid clearance. Green tea extract also significantly elevated serum antioxidant capacity with a positive dosage effect. The effect of GTE on SUA in healthy individuals was short term. The effects of GTE on urate handling in patients with hyperuricemia or gout need to be determined.

Background: The urate levels and the correlations of urate levels between the serum and synovial fluid (SF) of many arthritic diseases have not been well described., Objective: Compare urate levels in the serum and SF of gouty arthritis, calcium pyrophosphate dihydrate deposition disease (CPPD), rheumatoid arthritis (RA), septic arthritis, ankylosing spondylitis (AS), and osteoarthritis (OA) patients., Material and Method: Paired samples of serum and SF from 95 patients comprised of 33 patients with gout, 22 with CPPD, 18 with RA, nine with septic arthritis, three with AS, and 10 with OA were collected simultaneously for urate measurement by photometric test., Results: Ninety-five patients, including 53 males, with mean (SD) age of 64.1 (15.3) years were recruited. In gout, serum and SF urate levels were significantly higher than those of CPPD, RA, septic arthritis, AS, and OA ( p 0..01). In all the study population, the serum/SF ratios of urate levels of gout were not different across all groups. However, after excluding 24 patients with creatinine >1.5 mg/dl, the serum/SF ratios of urate were significantly lower in gout compared with the others ( 0.02). There were strongly positive correlations between serum and SF urate levels in gout similar to CPPD, RA, septic arthritis, AS, an dOA (r = 0.81-0.91, p 0O.01)., Conclusion: Despite the highest level of serum and SF urate across all groups, the serum/SF urate ratio in gout patients was the lowest, which suggests that SF urate levels are uniquely higher than their serum. In addition, the levels of serum urate of the entire groups strongly reflect their SF levels.

Background The side effect of allopurinol was severe allopurinol hypersensitivity (SAH). There are two major causes including genetic risk factor, HLA-B*58:01 and non-genetic risk factors including female, old age, renal impairment, inadequate starting dosage of allopurinol and received diuretic. Although HLA-B*58:01 testing is recommended in Thai, the several problems including cost, limitation of the testing and the delay of the result. Therefore, we aimed to use these non-genetic risk factors for developing the model to predict SAH. Method The study was a retrospective observational incidence density sampling. SAH cases were collected from tertiary care medical center which some cases were referred from primary care medical center; where most non-SAH cases were collected from primary care hospitals and tertiary care medical centers. The data of non-genetic factors particularly sex, age, renal function, co-diuresis, starting dosage of allopurinol and serum uric acid (SUA) of non-SAH cases selected the first description of allopurinol. The binary prevalence-weighted logistic regression statistical method was used to develop the prediction models. Three models were developed following general practice. Result Totally, there were 209 cases of SAH and 23,068 cases of non-SAH. Factors that were associated with the development of SAH within 90 days were female, old age (¿ 65 years old), renal impairment, inadequate starting dosage of allopurinol, co-medication(s) with diuretic and high SUA before prescription of allopurinol. Model 1a and model 1b were applied for patients who did not have and have SUA when starting allopurinol, respectively. Model 2 was applied for patients who had all non-genetic risk factors and started allopurinol within 60 days but have not SAH. The area under the receiver operating characteristic curve for model 1a, model 1b and model 2 were 0.72, 0.81 and 0.82, respectively (Figure 1). The performance for each predictions SAH were good. Conclusion Model 1a and model 1b predict SAH for the patients who had their first prescribed allopurinol, model 2 predicts SAH for the patients who had been taken allopurinol within 60 days but no SAH. The scoring system of each model helps clinician to prescribe allopurinol in real clinical practice before the patients develop SAH. The score of 0-1%, 1-2% and 2-100% indicates the low, moderate and high risk, respectively. The low-risk group can start allopurinol. The moderate-risk group considers to start allopurinol with closed monitoring of SAH. The high-risk group suggests to change to other urate lowering agents for preventing SAH (Table 1). [ABSTRACT FROM AUTHOR]

Thalassemia patients have a high cell turnover rate due to chronic hemolysis and ineffective erythropoiesis; therefore, hyperuricemia is anticipated. This study aimed to identify the prevalence of hyperuricemia, gout and nephrolithiasis, conditions associated with serum uric acid (SUA), and urine uric acid excretion (UUA) in thalassemia patients. This was a cross-sectional study in patients aged 15 years or older at Chiang Mai University Hospital. All patients had blood and 24-h urine collection test. We enrolled 112 thalassemia patients in which 67.0% were female, 64.3% had beta thalassemia/Hb E, 76.8% were transfusion dependent, and 59.8% were post splenectomy. The median age was 29 (16-58) years. Mean SUA was 6.7 ± 2.0 mg/dl and hyperuricemia (SUA > 6.8 mg/dl) was found in 47 cases (45.2%). Intact spleen (ORs 4.3, 95%CI 1.55-12.50, p = 0.01) and lower FEuric (ORs 2.08, 95%CI 1.35-3.33, p < 0.01) were associated with hyperuricemia significantly. Seven (6.3%) had gouty arthritis and nine (8%) had microscopic hematuria, one case being confirmed nephrolithiasis. The mean UUA excretion was 981.3 ± 335.0 mg/day and UUA hyperexcretion (> 700 mg/24 h) was found in 83.3%. UUA hyperexcretion patients had renal hyperfiltration 46%, glomerular dysfunction 84%, and tubular dysfunction 7.7%. From our study, hyperuricemia was found in approximately 40% of thalassemia patients but gouty arthritis occurred only in few patients (6%). This may be explained by urinary uric hyperexcretion which is found in over 80%. The significant risk factors for hyperuricemia were intact spleen and lower fraction excretion of uric acid. [ABSTRACT FROM AUTHOR]

Objective: To identify the best-performing survey definition of gout from items commonly available in epidemiologic studies.Methods: Survey definitions of gout were identified from 34 epidemiologic studies contributing to the Global Urate Genetics Consortium (GUGC) genome-wide association study. Data from the Study for Updated Gout Classification Criteria (SUGAR) were randomly divided into development and test data sets. A data-driven case definition was formed using logistic regression in the development data set. This definition, along with definitions used in GUGC studies and the 2015 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) gout classification criteria were applied to the test data set, using monosodium urate crystal identification as the gold standard.Results: For all tested GUGC definitions, the simple definition of "self-report of gout or urate-lowering therapy use" had the best test performance characteristics (sensitivity 82%, specificity 72%). The simple definition had similar performance to a SUGAR data-driven case definition with 5 weighted items: self-report, self-report of doctor diagnosis, colchicine use, urate-lowering therapy use, and hyperuricemia (sensitivity 87%, specificity 70%). Both of these definitions performed better than the 1977 American Rheumatism Association survey criteria (sensitivity 82%, specificity 67%). Of all tested definitions, the 2015 ACR/EULAR criteria had the best performance (sensitivity 92%, specificity 89%).Conclusion: A simple definition of "self-report of gout or urate-lowering therapy use" has the best test performance characteristics of existing definitions that use routinely available data. A more complex combination of features is more sensitive, but still lacks good specificity. If a more accurate case definition is required for a particular study, the 2015 ACR/EULAR gout classification criteria should be considered. [ABSTRACT FROM AUTHOR]