Factors for achieving target serum uric acid levels after initiating urate-lowering therapy in patients with gout: results from the ULTRA registry.

Achieving target serum uric acid (SUA) levels is important in gout management. Guidelines recommend lowering SUA levels to < 6 mg/dL; however, many patients fail to reach this target, even with uric acid-lowering therapy (ULT). This study investigated clinical characteristics of target SUA achievers among Korean patients with gout. This study used data from the ULTRA registry, a nationwide inception cohort established in September 2021 that enrolls patients with gout who initiate ULT. Demographic, clinical, and laboratory data were collected at baseline; the 6-month follow-up. Patients were divided into two groups: target achievers (SUA level < 6 mg/dL at 6 months) and non-achievers. The mean participant (N = 117) age was 56.1 years, and 88.0% were male. At 6 months, 83 patients (70.9%) reached target SUA levels. Target achievers had better drug adherence (≥ 80%) to ULT (97.6% vs. 76.5%; p < 0.01) than non-achievers. Target non-achievers had a higher percentage of a family history of gout (32.4% vs. 10.8%; p < 0.01) and less antihypertensive agent use (38.2% vs. 59.0%; p = 0.03) than target achievers. Multivariate regression analysis revealed that good adherence to ULT, the absence of a family history of gout, and antihypertensive agent use were key factors associated with achieving target SUA levels at 6 months.

Korean guidelines for the management of gout.

Gout is the most common form of arthritis, with the prevalence increasing worldwide. The present treatment guidelines provide recommendations for the appropriate treatment of acute gout, management during the inter-critical period, and prevention of chronic complications. The guidelines were developed based on evidence-based medicine and draft recommendations finalized after expert consensus. These guidelines are designed to provide clinicians with clinical evidence to enable efficient treatment of gout.

Epidemiology and treatment-related concerns of gout and hyperuricemia in Korean.

Gout is the most common form of inflammatory arthritis that affects mainly middle-aged men, and there is clear evidence of an association between hyperuricemia and the risk for gout. Increasing prevalence of gout and hyperuricemia has been reported in many countries. The prevalence of gout and hyperuricemia are constantly increasing in Korea with the patients at risk for developing a variety of comorbidities. Although there have been studies on the association between gout or serum uric acid level and several neurodegenerative diseases, cancer, and cardiovascular mortality, the causal relationship between gout and these comorbidities are still unclear. The associations of substantial economic burden with hyperuricemia, gout attack, and suboptimal treatment are well known. Gout is a disease that requires lifelong management including lifestyle modification. However, gout is poorly managed worldwide although effective urate-lowering drugs exist. In this review, we addressed epidemiological studies and treatment-related problems in the Korean population with gout or hyperuricemia to obtain the best clinical outcomes and reduce their medical burden.

Korean guidelines for the management of gout.

Gout is the most common form of arthritis, with the prevalence increasing worldwide. The present treatment guidelines provide recommendations for the appropriate treatment of acute gout, management during the inter-critical period, and prevention of chronic complications. The guidelines were developed based on evidence-based medicine and draft recommendations finalized after expert consensus. These guidelines are designed to provide clinicians with clinical evidence to enable efficient treatment of gout.

Risk of cancer in Korean patients with psoriatic arthritis: a nationwide population-based cohort study.

OBJECTIVE: While many studies on the increased risk of cancer in patients with psoriasis are available, data on the risk of cancer in patients with psoriatic arthritis (PsA) are still scarce. We assessed the risk of cancer in patients with PsA in a nationwide population-based cohort in Korea. METHODS: From 2010 to June 2021, patients newly diagnosed with PsA and 1:10 age-matched and sex-matched controls were included in this study. The outcome was the incidence of overall and specific cancers. RESULTS: Total 162 cancers occurred in 4688 PsA patients (incidence rate 83.2 (95% CI 70.8 to 97.0) per 10 000 person-years) and 1307 cancers occurred in 46 880 controls (incidence rate 66.9 (95% CI 63.3 to 70.6) per 10 000 person-years). The adjusted HR (aHR) of overall cancer in PsA patients was 1.20 (95% CI 1.02 to 1.41). However, this significance disappeared when non-melanoma skin cancer (NMSC) was excluded (aHR 1.16, 95% CI 0.98 to 1.37). Among specific cancers, the risk of NMSC (aHR 3.64 (95% CI 1.61 to 8.23)), lymphoma (aHR 2.63 (95% CI 1.30 to 5.30)) and thyroid cancer (aHR 1.83 (95% CI 1.18 to 2.85)) was higher in patients with PsA than in controls. CONCLUSION: The risk of overall cancer was higher in patients with PsA than in the general population. Patients with PsA had increased risks of NMSC, lymphoma and thyroid cancer compared with the general population. Our findings suggest a need to conduct cancer screening by a detailed history and comprehensive clinical examination in patients with PsA.

Risk of acute myocardial infarction, stroke, and venous thromboembolism among patients with anti-neutrophil cytoplasmic antibody-associated vasculitis in South Korea: A nationwide population-based study.

OBJECTIVES: To investigate the incidence and risk of cerebro-cardiovascular comorbidities (stroke, acute myocardial infarction, venous thromboembolism, and pulmonary embolism) in anti-neutrophil cytoplasmic antibody-associated vasculitis using nationwide Korean population-based medical claims data. METHODS: We identified 1905 patients with newly diagnosed anti-neutrophil cytoplasmic antibody-associated vasculitis during 2009-2019. Incidence rates and hazard ratios with 95% confidence intervals were calculated to estimate the risk of cerebro-cardiovascular comorbidities in these patients and compared to age- and sex-matched controls (1:10) using the Cox proportional hazards model. RESULTS: Most patients had microscopic polyangiitis (42.5%), followed by granulomatosis with polyangiitis (29.1%) and eosinophilic granulomatosis with polyangiitis (28.4%). The annual incidence rate of anti-neutrophil cytoplasmic antibody-associated vasculitis in 2019 was 0.55 per 100,000 person-years. Cerebro-cardiovascular comorbidities occurred in 12.6%. Stroke was most common (64.6%), followed by venous thromboembolism (34.6%), pulmonary embolism (18.3%), and acute myocardial infarction (5.4%). Korean patients with anti-neutrophil cytoplasmic antibody-associated vasculitis were at a significantly (2.3 times) higher overall risk for cerebro-cardiovascular comorbidities than the general population (adjusted hazard ratios, 4.5, 3.1, and 2.0 times higher for pulmonary embolism, venous thromboembolism, and stroke, respectively). These findings were similar for patients with each subtype of anti-neutrophil cytoplasmic antibody-associated vasculitis. CONCLUSIONS: This is the first nationwide population-based study to demonstrate a significant risk of cerebro-cardiovascular comorbidities as complications of anti-neutrophil cytoplasmic antibody-associated vasculitis in Korean patients. Knowing these risks may enable personalized patient care and improve overall survival.

Higher Levels of Serum Uric Acid Have a Significant Association with Lower Incidence of Lower Urinary Tract Symptoms in Healthy Korean Men.

Gout has been correlated with the risk of incident benign prostatic hyperplasia. In line with increasing prevalence of hyperuricemia, the aim of this study was to investigate the relationship between serum uric acid (SUA) level and the incidence of lower urinary tract symptoms (LUTS) among clinically healthy middle-aged men. We performed a cohort study in 101,091 Korean men without LUTS at baseline who completed health checkups between 2011 and 2016. LUTS were evaluated using the International Prostate Symptom Score, where a score ≥ 8 was defined as significant LUTS. Men were divided into six groups according to their SUA levels in mg/dL (<5.5, 5.5−6.4, 6.5−7.4, 7.5−8.4, 8.5−9.4, and ≥9.5). Throughout the follow-up­encompassing a total of 358,982.6 person years­13,424 people had significant LUTS (37.3 per 1000 person years for incidence rate). The multivariable models demonstrated that the highest level of SUA (≥9.5 mg/dL) was related to the lowest risk of significant LUTS compared with the reference category (<5.5 mg/dL) (0.77 (95% CI 0.59−0.99) for adjusted HR). In this large cohort composed of middle-aged men, higher SUA levels were related to a reduced risk of LUTS. This result suggests another potential role of SUA in restraining LUTS. Additional studies are needed to explain the underlying biological mechanisms of this phenomenological relationship.

Relationship Between Changing Body Mass Index and Serum Uric Acid Alteration Among Clinically Apparently Healthy Korean Men.

OBJECTIVE: Gout and hyperuricemia incidence is increasing worldwide, reflecting pandemic overweight and obesity. However, the magnitude of the association of body mass index (BMI) changes with serum uric acid (UA) level in the general population has remained unevaluated. METHODS: This retrospective cohort study enrolled 27,422 Korean men who underwent a comprehensive health check-up between 2015 and 2017. BMI change was categorized into 7 groups. The relationship between BMI change and serum UA level alteration was determined using multivariable regression models. RESULTS: The mean age, BMI, and serum UA level were 38.8 years, 24.7 kg/m2 , and 6.2 mg/dl, respectively. All BMI change categories had a clear dose-response relationship with the serum UA level changes. The corresponding ß coefficient of serum UA level changes was 0.13 (95% confidence interval [95% CI] 0.11, 0.16), 0.25 (95% CI 0.2, 0.3), and 0.44 (95% CI 0.36, 0.52) for a BMI decrease of 0.5-1.5, 1.5-2.5, and ≥2.5, respectively. Compared with no BMI change, the multivariate odds ratios of achieving normouricemia for a BMI increase of 0.5-1.5, 1.5-2.5, and ≥2.5 were 0.88 (95% CI 0.83, 0.95), 0.67 (95% CI 0.60, 0.75), and 0.60 (95% CI 0.49, 0.74), whereas those for a BMI decrease of 0.5-1.5, 1.5-2.5, and ≥2.5 were 1.17 (95% CI 1.07, 1.27), 1.28 (95% CI 1.08, 1.52), and 1.46 (95% CI 1.13, 1.88), respectively. CONCLUSION: BMI change could have a significant association with the alteration of serum UA levels of apparently healthy men. Despite its small effect size, the health risks and benefits of BMI change would be emphasized for serum UA level alteration.

Isomer-Specific Monitoring of Sialylated N-Glycans Reveals Association of α2,3-Linked Sialic Acid Epitope With Behcet's Disease.

Behcet's disease (BD) is an immune disease characterized by chronic and relapsing systemic vasculitis of unknown etiology, which can lead to blindness and even death. Despite continuous efforts to discover biomarkers for accurate and rapid diagnosis and optimal treatment of BD, there is still no signature marker with high sensitivity and high specificity. As the link between glycosylation and the immune system has been revealed, research on the immunological function of glycans is being actively conducted. In particular, sialic acids at the terminus of glycoconjugates are directly implicated in immune responses, cell-cell/pathogen interactions, and tumor progression. Therefore, changes in sialic acid epitope in the human body are spotlighted as a new indicator to monitor the onset and progression of immune diseases. Here, we performed global profiling of N-glycan compositions derived from the sera of 47 healthy donors and 47 BD patients using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) to preferentially determine BD target glycans. Then, three sialylated biantennary N-glycans were further subjected to the separation of linkage isomers and quantification using porous graphitized carbon-liquid chromatography (PGC-LC)/multiple reaction monitoring (MRM)-MS. We were able to successfully identify 11 isomers with sialic acid epitopes from the three glycan compositions consisting of Hex5HexNAc4NeuAc1, Hex5HexNAc4Fuc1NeuAc1, and Hex5HexNAc4NeuAc2. Among them, three isomers almost completely distinguished BD from control with high sensitivity and specificity with an area under the curve (AUC) of 0.945, suggesting the potential as novel BD biomarkers. In particular, it was confirmed that α2,3-sialic acid at the terminus of biantennary N-glycan was the epitope associated with BD. In this study, we present a novel approach to elucidating the association between BD and glycosylation by tracing isomeric structures containing sialic acid epitopes. Isomer-specific glycan profiling is suitable for analysis of large clinical cohorts and may facilitate the introduction of diagnostic assays for other immune diseases.

Patient Perspectives and Preferences Regarding Gout and Gout Management: Impact on Adherence.

BACKGROUND: Patient-centered management is becoming increasingly important in gout, but there are limited studies exploring patients' perspectives and preferences. We aimed to investigate patients' perspectives and preferences regarding gout and gout management, and their impacts on adherence to urate lowering therapy (ULT). METHODS: A paper-based survey was performed in patients with gout seen at the rheumatology outpatient clinics of 16 tertiary hospitals. The survey included questions regarding demographics, comorbidities, gout attacks, current treatment and adherence, and patients' perspectives and preferences regarding gout and gout management. Multivariate regression analysis was performed to determine the factors associated with ULT adherence. RESULTS: Of 809 surveyed patients with gout, 755 (94.5%) were using ULT. Among those using ULT, 89.1% had ≥ 80% adherence to ULT. Majority of the patients knew management strategies to some extent (94.8%), perceived gout as a life-long disease (91.2%), and were making efforts toward practicing at least one lifestyle modification (89.2%). Most patients (71.9%) obtained information about gout management during their clinic visits. Approximately half of the patients (53.6%) preferred managing their disease with both ULT and lifestyle modification, 28.4% preferred ULT only, and 17.4% preferred lifestyle modification only. Adherence was better in patients with older age (odds ratio [OR], 1.03), those with better knowledge of gout management strategies (OR, 3.56), and those who had preference for ULT (OR, 2.07). CONCLUSION: Patients' perspectives and management preferences had high impacts on adherence to ULT in gout. Consideration of patients' perspectives and preferences is important for achieving the desired clinical outcome in gout.

How much does fat mass change affect serum uric acid levels among apparently clinically healthy Korean men?

OBJECTIVE: The aim of this study was to examine the impact of fat mass alteration on serum uric acid (SUA) levels in apparently clinically healthy men. METHODS: We evaluated 27,387 men who consecutively underwent health check ups between 2015 and 2017. We assessed the likelihood of achieving a SUA level of <0.41 mmol/L and compared the SUA levels according to fat mass changes. RESULTS: Compared with those without fat mass change (the reference group), the odds ratios (95% confidence interval) of achieving a SUA level of <0.41 mmol/L for fat mass decreases of ⩾2.5, 1.5-2.5, and 0.5-1.5 kg were 1.63 (1.45-1.82), 1.19 (1.06-1.34), and 1.07 (0.97-1.18), respectively, while those for a fat mass increase of ⩾2.5, 1.5-2.5, and 0.5-1.5 kg were 0.71 (0.64-0.78), 0.87 (0.79-0.97), and 0.95 (0.86-1.04), respectively. The corresponding beta-coefficients of SUA levels (mmol/L) were -0.26 [-0.29-(-0.23)], -0.12 [-0.16-(-0.09)], and -0.09 [-0.12-(-0.06)] for fat mass decreases of ⩾2.5, 1.5-2.5, and 0.5-1.5 kg, respectively. Every 1-kg fat mass reduction was associated with 9% increased odds of achieving the target SUA level. The multivariate SUA level difference per 1-kg fat mass gain was 2.97 µmol/L. Similar levels of association persisted among the prespecified subgroups. CONCLUSION: We quantitatively demonstrated that fat mass reduction contributes to a clinically relevant decrease in SUA levels and a significant increase in the likelihood of achieving target SUA levels. Our findings may help to provide clear clinical guidance on fat mass alteration to reduce SUA levels in patients with hyperuricemia.

Incidence and risk of developing rheumatic diseases in 19,724 patients with palindromic rheumatism in South Korea: A nationwide population-based study.

OBJECTIVES: The spectrum of progression of palindromic rheumatism (PR) to chronic diseases is quite variable. Hence, this study aimed to investigate the incidence and risk of developing rheumatic diseases in PR using nationwide, population-based medical claims data from Korea. METHODS: We assessed the incidence rate (IR) of PR in the population in the given year. After matching individuals with PR with those without PR (1:10) for age, gender, and the index year, we calculated the hazard ratios (HRs) with 95% confidence intervals (CIs) using the Cox proportional hazard model. RESULTS: A total of 19,724 newly diagnosed incident PR cases were identified from 2010 to 2016. The mean age was 50.2±14.9 years. The incidence of PR was 7.02 (95% CI 6.92-7.12) per 100,000 person-years (6.22 and 7.80 in men and women, respectively). During observation, 8.79% patients with PR and 0.30% individuals without PR developed various outcome diseases. Patients with PR had an increased risk of seropositive rheumatoid arthritis (HR 46.51, 95% CI [41.05-52.69]), psoriatic arthritis (44.79 [15.16-132.35]), systemic lupus erythematosus (24.53 [16.15-37.24]), mixed connective tissue disease (22.01 [7.65-63.34]), Behçet's disease (21.04 [13.81-32.06]), Sjögren's syndrome (12.36 [8.54-17.88]), ankylosing spondylitis (9.00 [6.67-12.15]), dermatomyositis/polymyositis (6.14 [2.55-14.82]), and systemic sclerosis (3.75 [1.47-9.58]) compared with individuals without PR. CONCLUSIONS: This nationwide, population-based cohort study demonstrated that about one-eleventh of patients with PR eventually develop systemic rheumatic diseases and that patients with PR have an increased risk of developing various rheumatic diseases including seropositive rheumatoid arthritis.

The Practice Guideline for Vaccinating Korean Patients with Autoimmune Inflammatory Rheumatic Disease.

To develop a clinical practice guideline for vaccination in patients with autoimmune inflammatory rheumatic disease (AIIRD), the Korean College of Rheumatology and the Korean Society of Infectious Diseases developed a clinical practice guideline according to the clinical practice guideline development manual. Since vaccination is unlikely to cause AIIRD or worsen disease activities, required vaccinations are recommended. Once patients are diagnosed with AIIRD, treatment strategies should be established and, at the same time, monitor their vaccination history. It is recommended to administer vaccines when the disease enters the stabilized stage. Administering live attenuated vaccines in patients with AIIRD who are taking immunosuppressants should be avoided. Vaccination should be considered in patients with AIIRD, prior to initiating immunosuppressants. It is recommended to administer influenza, Streptococcus pneumoniae, hepatitis A, hepatitis B, herpes zoster, measles-mumps-rubella virus, human papillomavirus, and tetanus-diphtheria-pertussis vaccines in patients with AIIRD; such patients who planned to travel are generally recommended to be vaccinated at the recommended vaccine level of healthy adults. Those who live in a household with patients with AIIRD and their caregivers should also be vaccinated at levels that are generally recommended for healthy adults.

Systematic re-evaluation of the long-used standard protocol of urease-dependent metabolome sample preparation.

In the urinary metabolomics for finding biomarkers in urine, owing to high concentrations of urea, for chromatography-based metabolomic analysis, urea needed to be degraded by urease. This urease pretreatment has been the key step of sample preparation for standard urinary metabolomics until today even for mass spectrometry-based analysis. The urease pretreatment involving incubation of urine with urease contradicts the concept of metabolome sampling, which should immediately arrest metabolic reactions to prevent alterations of a metabolite profile. Nonetheless, the impact of urease pretreatment has not been clearly elucidated yet. We found that activities of urease and endogenous urinary enzymes and metabolite contaminants from the urease preparations introduce artefacts into metabolite profiles, thus leading to misinterpretation.

Risk of non-Hodgkin's lymphoma and thyroid cancer in primary Sjögren's syndrome measured using the Korean Health Insurance Claims Database.

OBJECTIVES: The aim of this study was to evaluate the incidence and risk of non-Hodgkin's lymphoma (NHL) and thyroid cancer in patients with primary Sjögren's syndrome (pSS) using the Korean National Health Insurance Service (NHIS) claims database. METHODS: pSS was identified using the Korean NHIS medical claims database between 2007 and 2017. The case definition required more than one visit based on the SS diagnostic code and the registration system for rare and incurable diseases. We included all admissions with a primary diagnosis of lymphoma and thyroid cancer. RESULTS: The pSS incidence was 1.88 cases/100,000 inhabitants. Female patients had a higher incidence than male patients, with a female-to-male ratio of 7.65:1. Of those, we identified 18 (0.34%), 1 (0.02%) and 29 (0.56%) patients with NHL, Hodgkin's disease and thyroid cancer, respectively. For pSS, the standardised incidence ratios for NHL and thyroid cancer were 6.32 (95% confidence interval [CI] 4.09-9.38) and 1.23 (95% CI 0.88-1.68), respectively. Compared with the general population, female patients with pSS had a 6.95-fold higher risk of developing NHL, while the male patients did not. Patients with pSS did not have a higher risk of developing thyroid cancer. CONCLUSIONS: Although pSS is associated with a higher risk of developing NHL, the risk of NHL appears to have decreased compared with that in previous studies. Our study suggests that the risk of NHL or thyroid cancer with SS is not higher than that reported in previous studies.

Variation in the synovial fluid metabolome according to disease activity of rheumatoid arthritis.

OBJECTIVES: Because genetic and environmental factors both contribute to rheumatoid arthritis (RA), metabolomics could be a very useful tool to elucidate the pathophysiology of RA, and to predict response to treatment. This study was carried out to investigate synovial fluid (SF) metabolic perturbation in RA patients according to the degree of disease activity using gas chromatography/time-of-flight mass spectrometry (GC/TOF MS). METHODS: SF samples were obtained from 48 RA patients. Disease activity was assessed using DAS28-ESR(3). SF metabolomics profiling was performed using GC/TOF-MS, in conjunction with multivariate statistical analyses and pathway analyses. RESULTS: Significant discrimination of metabolite profiles between moderate and high disease activity groups was shown by PLS-DA, which provided evidence that SF metabolic profiles predicted disease activity. We found the significant correlation between DAS28-ESR(3) value and the intensities of 12 metabolites. The intensities of glycocyamine and indol-3-lactate positively correlated with DAS28-ESR(3) value. On the other hand, ß-alanine, asparagine, citrate, cyano-L-alanine, leucine, nicotinamide, citrulline, methionine, oxoproline, and salicylaldehyde negatively correlated with DAS28-ESR(3) value. We found fifteen pathways that were significantly associated with disease activity in RA and that the higher the disease activity, the more amino acid metabolic processes were affected. CONCLUSIONS: We found the SF metabolic alterations in RA patients according to disease activity by using GC/TOF MS and identified 12 candidate metabolic biomarkers that may well reflect the disease activity of RA. SF metabolomic approaches based on GC/TOF MS might provide additional information relating to monitoring disease activity in RA.

Higher serum uric acid is associated with higher lumbar spine bone mineral density in male health-screening examinees: a cross-sectional study.

Bone health has been associated with oxidative stress and antioxidants have received interest to this end. Serum uric acid (SUA), an end product of purine metabolism in humans, has recently shown antioxidant properties regarding bone health, but there are conflicting results. The aim of this study was to investigate the relationship between SUA levels and lumbar spine bone mineral density (BMD) in clinically apparently healthy males aged 40-60 years. We performed a cross-sectional study of 6588 Korean males who completed a health-screening program from January 2011 to December 2014. Of the study participants, the mean age was 48.2 ± 10.7 years. Multiple regression analyses resulted in a significant positive association with lumbar spine BMD across SUA quintiles in a dose-response manner after adjusting for various confounding factors (p = 0.013); for each 1 mg/dl increase of SUA, BMD rose by 0.0054 g/cm2 (p = 0.004). Stratified analyses revealed that this association between SUA and lumbar spine BMD was consistently observed across all clinically relevant subgroups. The present study demonstrated a positive association in males between SUA and lumbar spine BMD, suggesting that SUA could have a profitable effect on bone metabolism.

Association between serum uric acid and arterial stiffness in a low-risk, middle-aged, large Korean population: A cross-sectional study.

We investigated the association between serum uric acid (SUA) and brachial ankle pulse wave velocity (baPWV) in an apparently healthy population. We performed a cross-sectional study on middle-aged Koreans who completed a yearly health-screening program between January and December 2014. Subjects with coronary artery disease, diabetes, or hypertension were excluded. Linear regression analyses were used to study the relationship between SUA and baPWV. Multiple adjustments were made for variables based on clinical or statistical significance. Of 66,917 study participants (38,170 men and 28,747 women), the mean age was 39.4 ±â€Š6.7 years and the average SUA level was 5.23 ±â€Š1.4 mg/dL. SUA values were higher in men than in women (6.1 ±â€Š1.2 mg/dL vs. 4.1 ±â€Š0.8 mg/dL). SUA was linearly associated with baPWV in women and in men (P < .001, respectively). Multiple regression analyses remained significant for women with a positive association with baPWV across SUA quintiles in a dose-response manner (P < .001) while no longer for men with a J-shaped association between SUA quintiles and baPWV. When SUA modeled continuously, baPWV rose by 12.413 cm/s in women (P < .001) and by 6.588 cm/s in men (P < .001) for each 1 mg/dL increase of SUA. In a low-risk, middle-aged, large Korean population, higher SUA levels could have an unfavorable impact on arterial stiffness as measured by baPWV, and this association was stronger in women than in men.

Drug survival of tumor necrosis factor α inhibitors in patients with ankylosing spondylitis in Korea.

BACKGROUND/AIMS: To evaluate drug survival of the tumor necrosis factor α inhibitors (TNFi) and risk factors for the drug discontinuation in patients with ankylosing spondylitis (AS). METHODS: We retrospectively evaluated 487 AS patients at a single tertiary hospital. Among the TNFi users, drug survival and risk factors of TNFi discontinuation were investigated. RESULTS: Among 487 patients, 128 AS patients were treated with at least one TNFi. Patients who were treated with TNFi were younger at disease onset, had more peripheral manifestations, and had higher level of acute phase reactants and body mass index than those of TNFi non-users at baseline. Of 128 patients, 28 patients (21.9%) discontinued first TNFi therapy during the follow-up period of 65.1 ± 27.9 months. In the multivariable analysis, female (hazard ratio [HR], 6.08; 95% confidence interval [CI], 2.27 to 16.27; p = 0.003), hip involvement (HR, 2.52; 95% CI, 1.08 to 5.87; p = 0.033) and a high C-reactive protein (CRP; HR, 1.10; 95% CI, 1.00 to 1.21; p = 0.044) were risk factors for drug discontinuation. Etanercept showed better survival rate than infliximab. The main reason for discontinuation of TNFi was inefficacy. CONCLUSIONS: TNFi discontinuation rate of Korean patients with AS seems to be similar to those with the European patients. Female sex, hip involvement, CRP, and the type of TNFi were associated with TNFi discontinuation.

Potential metabolomic biomarkers for reliable diagnosis of Behcet's disease using gas chromatography/ time-of-flight-mass spectrometry.

OBJECTIVES: Although many diagnostic criteria of Behcet's disease (BD) have been developed and revised by experts, diagnosing BD is still complicated and challenging. No metabolomic studies on serum have been attempted to improve the diagnosis and to identify potential biomarkers of BD. The purposes of this study were to investigate distinctive metabolic changes in serum samples of BD patients and to identify metabolic candidate biomarkers for reliable diagnosis of BD using the metabolomics platform. METHODS: Metabolomic profiling of 90 serum samples from 45 BD patients and 45 healthy controls (HCs) were performed via gas chromatography with time-of-flight mass spectrometry (GC/TOF-MS) with multivariate statistical analyses. RESULTS: A total of 104 metabolites were identified from samples. The serum metabolite profiles obtained from GC/TOF-MS analysis can distinguish BD patients from HC group in discovery set. The variation values of the partial least squared-discrimination analysis (PLS-DA) model are R2X of 0.246, R2Y of 0.913 and Q2 of 0.852, respectively, indicating strong explanation and prediction capabilities of the model. A panel of five metabolic biomarkers, namely, decanoic acid, fructose, tagatose, linoleic acid and oleic acid were selected and adequately validated as putative biomarkers of BD (sensitivity 100%, specificity 97.1%, area under the curve 0.998) in the discovery set and independent set. The PLS_DA model showed clear discrimination of BD and HC groups by the five metabolic biomarkers in independent set. CONCLUSIONS: This is the first report on characteristic metabolic profiles and potential metabolite biomarkers in serum for reliable diagnosis of BD using GC/TOF-MS.