Impact of socioeconomic status on biologics utilization in rheumatoid arthritis: revealing inequalities and healthcare efficiency

Background/Aims

This cross-sectional study aimed to investigate biologics treatment disparities in rheumatoid arthritis (RA) patients based on socioeconomic status (SES).

Methods

Data from the KOrean Observational Study Network for Arthritis (KORONA) database were analyzed to assess various factors associated with SES, health behaviors, and biologics use. Logistic regression and structured equation modeling (SEM) were utilized for data analysis.

Results

Among 5,077 RA patients included, 393 (7.7%) patients were identified as biologics users. Within the entire cohort, 31.8% of the participants were in the low-income and low-education groups, and 39.3% of the participants were in the high-income and high-education groups. Despite the patients with low income or low education experienced higher disease activity at diagnosis, had more comorbidities, exhibited higher medication compliance, underwent more check-ups, and had more hospital admissions than their counterparts, the odds of patients with low-income receiving biologics were 34% lower (adjusted odds ratio = 0.76, 95% confidence interval: 0.60-0.96, p = 0.021) after adjustment for demographics and comorbidities. SEM and pathway analyses confirmed the negative impact of low SES on biologics use.

Conclusions

The findings suggest that SES plays a significant role in biologics use among RA patients, indicating potential healthcare inefficiencies for low SES patients. Moreover, adverse healthcare habits negatively affect biologics use in RA patients. The study highlights the importance of considering socioeconomic factors while discussing biologics use and promoting equitable access to biologics for optimal RA management.

All-cause and cause-specific mortality among patients with Behçet's disease versus the general population

BACKGROUND

Comparative risk regarding cause-specific mortality between patients with Behcet's disease (BD) and the general population is not known.

OBJECTIVES

To compare the risk of all-cause and cause-specific mortality among patients with BD versus the general population.

METHODS

Using the 2002-2020 Korea National Health Insurance Service database, we conducted a cohort study comparing BD patients and the general population matched on age and sex at a 1:4 ratio. We used Cox proportional hazard models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortality. Subgroup analyses by age and sex were done.

RESULTS

We included 24,669 BD patients and 98,676 age- and sex-matched controls (mean age 40.5 years, 34% male). During a mean follow-up of 11.9 years, the incidence rate of death per 100 person-years was 0.36 in BD and 0.29 in controls with the HR (95% CI) of 1.28 (1.20-1.38). The risk of mortality was highest for one year after BD diagnosis showing a HR (95% CI) of 2.66 (2.09-3.40). BD patients died more in this period due to malignancy, cardiovascular (CV), gastrointestinal, and respiratory disease, and infection: the corresponding cause-specific HR (95% CI) was 1.96 (1.30-2.98), 2.68 (1.45-4.97), 3.50 (1.35-9.07), 5.00 (1.34-18.62), and 3.33 (1.02-10.92), respectively. Mortality by neurological (HR 1.58, 95% CI 1.06-2.35) and genitourinary disease (HR 2.20, 95% CI 1.43-3.37) was also more common in BD during the overall follow-up. Subgroup analyses showed consistent results. The risk of CV mortality compared to the general population was higher in the young than elderly (p for interaction = 0.006), and the risk of gastrointestinal mortality in women than men (p for interaction = 0.04).

CONCLUSIONS

This population-based cohort study shows the first year of the disease as the highest risk window for excess mortality among BD patients. The mortality burden in BD derived from a wide spectrum of organ involvements, warning clinicians about the systemic nature of the disease.

Risk-Benefit Analysis of Primary Prophylaxis Against Pneumocystis Jirovecii Pneumonia in Patients With Rheumatic Diseases Receiving Rituximab

OBJECTIVE

To identify a specific population of patients with rheumatic diseases receiving rituximab treatment for whom the benefit from primary prophylaxis against Pneumocystis jirovecii pneumonia (PJP) outweighs the risk of adverse events (AEs).

METHODS

This study included 818 patients treated with rituximab for rheumatic diseases, among whom 419 received prophylactic trimethoprim/sulfamethoxazole (TMP/SMX) with rituximab, while the remainder did not. Differences in 1-year PJP incidence between the groups were estimated using Cox proportional hazards regression. Risk-benefit assessment was performed in subgroups stratified according to risk factors based on the number needed to treat (NNT) to prevent 1 case of PJP and the number needed to harm (NNH) due to severe AEs. Inverse probability of treatment weighting was applied to minimize the confounding by indication.

RESULTS

During the 663.1 person-years, there were 11 PJP cases, with a mortality rate of 63.6%. Concomitant use of high-dose glucocorticoids (≥30 mg/day of prednisone or equivalent during 4 weeks after rituximab administration) was the most important risk factor. The PJP incidence (per 100 person-years) was 7.93 (95% confidence interval [95% CI] 2.91-17.25) in the subgroup receiving high-dose glucocorticoids compared with 0.40 (95% CI 0.01-2.25) in the subgroup without high-dose glucocorticoid use. Although prophylactic TMP/SMX significantly reduced the overall PJP incidence (HR 0.11 [95% CI 0.03-0.43]), the NNT to prevent 1 case of PJP (146) was higher than the NNH (86). In contrast, the NNT fell to 20 (95% CI 10.7-65.7) in patients receiving concomitant high-dose glucocorticoids.

CONCLUSION

The benefit associated with primary PJP prophylaxis outweighs the risk of severe AEs in patients with rheumatic diseases receiving rituximab and concomitant high-dose glucocorticoid treatment.

Recurrent focal myofasciitis of Behçet syndrome mimics infectious myofasciitis: a case report

Behçet syndrome (BS) is a chronic inflammatory disease with multiorgan manifestations. However, muscular involvement in BS has rarely been reported. Herein, we report the case of a 30-year-old male with BS who had recurring pain and swelling of the lower legs. The patient was administered antibiotics on several occasions as the condition was misinterpreted to be infectious myositis. Magnetic resonance imaging revealed myofascial involvement with focal necrotic lesions, and muscle biopsy revealed acute suppurative myositis with perivascular infiltration of polymorphonuclear leukocytes. His symptoms improved after treatment with corticosteroids. Azathioprine and colchicine therapy was beneficial for preventing further relapse after short-term corticosteroid treatment. Therefore, BS should be considered in the differential diagnosis of focal suppurative myofasciitis.

Anterior and Lateral Femoroacetabular Excursion Angles Are Helpful for Assessing Femoroacetabular Impingement Syndrome: A Cross-Sectional Cohort Study

PURPOSE

To develop a radiographic measurement to evaluate the femoroacetabular space using 3-dimensional (3D) hip models in asymptomatic hips, and to evaluate the reliability and validity of the femoroacetabular excursion angle (FAEA) in symptomatic patients.

METHODS

From January 2020 to December 2020, we recruited patients with healthy hips to establish 3D models. Through the simulation of 14 activities of daily living (ADLs), anterior and lateral impingement-free FAEAs were measured. Another cross-sectional cohort was formed from consecutive symptomatic subjects with impingement signs during the same period. In the validation cohort, anterior and lateral FAEAs were assessed on modified Dunn's and anteroposterior views of the hip, respectively. We evaluated the reliability and clinical implications of the FAEAs.

RESULTS

In the discovery cohort (n = 33), hips with collisions tended to have smaller computed tomography-based FAEAs than collision-free hips, although alpha and lateral center-edge (CE) angles were comparable. Additionally, hips with a lower quartile of FAEAs had a significantly higher number of ADLs with collisions. In the validation cohort (n = 411), the FAEA measurement was highly reliable (kappa statistics >0.95 for both interobserver and intraobserver reliabilities). The femoroacetabular impingement syndrome (FAIS) group (n = 165) showed significantly smaller anterior and lateral FAEAs than the non-FAIS group (all P < .001, Cramer V = .420). The optimal cut-off values for anterior and lateral FAEAs were 32.6° and 48.9°, respectively. In univariate regression, anterior (odds ratio [OR] = 0.91; 95% confidence interval [CI] = 0.89-0.94) and lateral (OR = 0.91; 95% CI = 0.89-0.93) FAEAs were significantly associated with FAIS. Moreover, in multivariate regression adjusted for alpha and lateral CE angles, anterior FAEA remained a significant predictor (OR = 0.96; 95% CI = 0.93-0.99), and small FAEA was an independent risk factor for FAIS (OR = 1.99; 95% CI = 1.06-3.71) for any small FAEA (OR = 2.88; 95% CI = 1.32-6.31) for both small FAEAs.

CONCLUSION

The FAEA is a valid measurement for FAIS with high reliability. Small FAEA was an independent risk factor for FAIS in the multivariate regression model, even after adjusting for alpha and lateral CE angles.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Lung function trajectory of rheumatoid arthritis-associated interstitial lung disease

OBJECTIVES

To explore the course of lung function and RA disease activity and predictive factors for deteriorating lung function in patients with RA-interstitial lung disease (ILD).

METHODS

The Korean Rheumatoid Arthritis-Interstitial Lung Disease cohort is a multicentre, prospective observational cohort. Patients with RA-ILD were enrolled and followed up annually for 3 years for RA disease activity and ILD status assessment. Group-based modelling was used to cluster a similar predicted percentage of forced vital capacity (FVC%) patterns into trajectories.

RESULTS

This study included 140 patients who underwent at least two pulmonary function tests. Four distinctive trajectories for predicted FVC% were 'improving' [n = 11 (7.9%)], 'stable' [n = 68 (38.4%)], 'slowly declining' [n = 54 (48.6%)] and 'rapidly declining' [n = 7 (5.0%)]. Most (77.7%) patients maintained or improved to low RA disease activity. The lung function trajectory was not comparable to the RA disease activity trajectory. Age ≥70 years [relative risk (RR) 10.8 (95% CI 1.30, 89.71)] and early RA diagnosed within the preceding 2 years [RR 10.1 (95% CI 1.22, 84.2)] were associated with increased risk for rapidly declining predicted FVC%. The risk for deterioration or mortality increased in patients with a simultaneous diagnosis of RA and ILD within 24 weeks [RR 9.18 (95% CI 2.05, 41.0)] and the extent of lung involvement [RR 3.28 (95% CI 1.12, 9.60)].

CONCLUSION

Most patients with RA-ILD experienced stable or slowly declining lung function. In 5% of patients, predicted FVC% deteriorated rapidly, especially in older adults with early RA. The lung function trajectory was not comparable to the RA disease activity trajectory.

Comparative risk of infections between JAK inhibitors versus TNF inhibitors among patients with rheumatoid arthritis: a cohort study

BACKGROUND

To compare infectious risk between JAK inhibitors (JAKis) versus TNF inhibitors (TNFis) among rheumatoid arthritis (RA) patients in Korea.

METHODS

Using 2009-2019 Korea National Health Insurance Service database, we conducted a cohort study on RA patients initiating a JAKi or TNFi. The primary outcomes were herpes zoster (HZ), serious bacterial (SBI), and opportunistic infections (OI). Propensity-score fine-stratification (PSS) and weighting were applied to adjust for > 70 baseline covariates. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models comparing JAKi versus TNFi users.

RESULTS

We included 2963 JAKi initiators PSS-weighted on 5169 TNFi initiators. During a follow-up of 1.16 years, the most frequent type of infections was HZ with incidence rate (IR) per 100 person-years of 11.54 and 4.88 in JAKi and TNFi users, respectively. The IR of SBI was 1.39 and 1.32, respectively. The OI was rare with a majority being tuberculosis and showed an IR of 0.11 and 0.49 in JAKi and TNFi users, respectively. The PSS-weighted HR (95% CI) for individual types of infections was 2.37 (2.00-2.80) for HZ, 1.04 (0.71-1.52) for SBI, and 0.25 (0.09-0.73) for OI.

CONCLUSIONS

This population-based cohort study on RA patients treated with JAKi or TNFi in Korea showed an exceptionally high IR of HZ in both treatment groups compared to that from Western countries, with an approximately doubled risk associated with JAKi versus TNFi use. The risk of SBI was comparable, but the risk of OI, particularly tuberculosis, was less among JAKi than TNFi initiators.

Methotrexate, leflunomide and tacrolimus use and the progression of rheumatoid arthritis-associated interstitial lung disease

OBJECTIVE

To examine the association between MTX, LEF and tacrolimus use and the progression of RA-associated interstitial lung disease (ILD).

METHODS

The Korean RA-ILD cohort prospectively enrolled patients with RA-associated ILD at multiple centres from 2015 to 2018 and followed up with them for 3 years. ILD progression was defined by any of the followings: a decrease of ≥10% in forced vital capacity, a decrease of ≥15% in the diffusing capacity of the lung for carbon monoxide, or death from respiratory failure.

RESULTS

Of 143 patients, 64 patients experienced ILD progression during a median follow-up period of 33 months. The use of MTX [adjusted hazard ratio (aHR), 1.06; 95% CI, 0.59, 1.89], LEF (aHR, 1.75; 95% CI, 0.88, 3.46) and tacrolimus (aHR, 0.94; 95% CI, 0.52, 1.72) did not increase the risk of ILD progression. However, the association between LEF use and the risk of ILD progression was significant in subgroups with poor lung function (aHR, 8.42; 95% CI, 2.61, 27.15). Older age, male sex, a shorter RA duration, higher RA disease activity and extensive disease at baseline were independently associated with ILD progression.

CONCLUSION

None of the three treatments increased the risk of RA-associated ILD progression, except for LEF, which increased the risk of ILD progression in patients with severe ILD. The appropriate use of conventional synthetic disease-modifying antirheumatic drugs considering RA disease activity and ILD severity would be important for the management of RA-associated ILD.

Impact of early age at menopause on disease outcomes in postmenopausal women with rheumatoid arthritis: a large observational cohort study of Korean patients with rheumatoid arthritis

OBJECTIVES

To assess the differences in clinical outcomes between patients with rheumatoid arthritis (RA) with early menopause (EM) (<45 years) and usual menopause (UM) (≥45 years) and to identify the impact of EM on longitudinal changes in RA activity and patient-reported outcomes (PROs).

METHODS

We recruited 2878 postmenopausal women with RA from the Korean Observational Study Network for Arthritis. Patients were examined at baseline and for 5 consecutive years using the Simplified Disease Activity Index (SDAI), Health Assessment Questionnaire-Disability Index (HAQ-DI) and other PROs. Generalised estimating equation (GEE) analyses were performed among patients with a baseline SDAI of >11 to evaluate the impact of EM on longitudinal changes in RA activity and PROs.

RESULTS

The EM group (n=437) was younger than the UM group (n=2441), but the RA duration was similar between the two groups. The EM group was more educated and more likely to be seronegative at enrolment. Moreover, the EM group demonstrated higher disease activity and worse PROs for global assessment, fatigue, sleep disturbance and health-related quality of life (HRQoL) (all p<0.05) at baseline. The GEE model revealed that EM significantly influenced the rate of SDAI change (β=1.265, p=0.004) after adjusting for age, RA duration, biologics use and SDAI at baseline. The EM group was also significantly associated with increased HAQ-DI scores and decreased EQ-5D-utility values during the 5-year follow-up period.

CONCLUSION

Patients with RA and EM demonstrate higher disease activity and poorer HRQoL. Furthermore, EM significantly affects the longitudinal changes in disease activity and PROs in patients with RA.

A Multicenter, Prospective, Randomized, Parallel-Group Trial on the Effects of Temporary Methotrexate Discontinuation for One Week Versus Two Weeks on Seasonal Influenza Vaccination in Patients With Rheumatoid Arthritis

OBJECTIVE

This clinical trial was conducted to investigate whether discontinuing methotrexate (MTX) for 1 week after seasonal influenza vaccination is noninferior to discontinuing for 2 weeks after vaccination in patients with rheumatoid arthritis (RA).

METHODS

In this multicenter, prospective, randomized, parallel-group noninferiority trial, RA patients receiving a stable dose of MTX were randomly assigned at a ratio of 1:1 to discontinue MTX for 1 week or for 2 weeks after they received the quadrivalent 2021-2022 seasonal influenza vaccine containing H1N1, H3N2, B/Yamagata, and B/Victoria strains. The primary outcome measure was the proportion of patients with a satisfactory vaccine response, which was defined as ≥4-fold increase in antibody titers, as determined with the hemagglutination inhibition assay, against ≥2 of the 4 vaccine strains at 4 weeks after vaccination.

RESULTS

The modified intent-to-treat population included 90 patients in the 1-week MTX hold group and 88 patients in the 2-week MTX hold group. The mean ± SD MTX doses were 12.6 ± 3.4 mg/week in the 1-week MTX hold group and 12.9 ± 3.3 mg/week in the 2-week MTX hold group. The proportion of satisfactory vaccine responses did not differ between the groups (68.9% versus 75.0%; P = 0.364). The rate of seroprotection and the fold increase in antibody titers for each of the 4 influenza antigens were similar between the groups.

CONCLUSION

A temporary discontinuation of MTX for 1 week after vaccination was noninferior to a discontinuation of MTX for 2 weeks after vaccination, regarding induction of a satisfactory vaccine response to a seasonal influenza vaccine in patients with RA receiving a stable dose of MTX.

The effect of rebamipide on non-steroidal anti-inflammatory drug-induced gastro-enteropathy: a multi-center, randomized pilot study

BACKGROUND/AIMS

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly-used medications, and ailments such as arthritis or heart disease, require long-term use of these drugs, which can induce gastroenteropathy with bleeding and ulcers. This study investigated the associations between efficacy, safety, and gastrointestinal symptoms linked to rebamipide and proton pump inhibitor administration in patients requiring long-term NSAID use.

METHODS

This study was a multi-center, randomized, open-labeled, pilot design.

RESULTS

Thirty-three patients were included. Of these, 15 were included in the study group and 18 were in the control group. NSAID-induced gastric ulcers, which were the primary outcome of this study, did not occur in either the study or control group. Changes in the number of small bowel erosions and ulcers were -0.6 ± 3.06 in the study group and 1.33 ± 4.71 in the control group. The number of subjects with mucosal breaks (defined as multiple erosions and/or ulcers) was three (20%) in the study group and six (40%) in the control group (p = 0.427). No serious adverse events occurred in either group. However, dyspepsia and skin rashes occurred in six patients (31.58%) in the study group and 13 (65%) in the control group (p = 0.036).

CONCLUSION

Although statistically significant differences were not generated, possibly as a result of the small sample size, mucosal breaks observed via capsule endoscopy revealed that rebamipide was likely to be more effective than lansoprazole in preventing small intestine damage caused by NSAIDs. Furthermore, fewer side-effects emerged with rebamipide.

Comparative risk of blindness and vision-threatening ocular comorbidities in patients with Behcet’s disease versus the general population

Objective

To compare the risk of blindness and vision-threatening ocular comorbidities in patients with Behçet’s disease (BD) vs the general population.

Methods

Using 2002–2017 Korea National Health Insurance Service database, we did a population-based cohort study comparing newly-diagnosed BD patients and age- and sex-matched non-BD controls at a 1:5 ratio. The primary outcome was blindness defined as a best-corrected visual acuity of ≤ 20/500 in the better-seeing eye. Secondary outcomes were vision-threatening ocular comorbidities (cataract, glaucoma, and retinal disorders) that require surgical interventions and incident uveitis. Cox proportional hazard models estimated hazard ratios (HRs) and 95% confidence intervals (CIs). We performed subgroup analyses by sex and BD diagnosis age.

Results

We included 31 228 BD patients and 156 140 controls. During a follow-up of 9.39 years, the incidence rate of blindness per 1000 person-years was 0.24 in BD and 0.02 in controls with the HR [95% CI] of 10.73 [7.10–16.22]. The HR [95% CI] for secondary outcomes was 2.06 [1.98–2.15] for cataract surgery, 5.43 [4.57–6.45] for glaucoma surgery, and 2.71 [2.39–3.07] for retinal surgery. The HR [95% CI] of incident uveitis was 6.19 [5.83–6.58]. Males suffered a disproportionately higher risk of blindness than females due to greater severity than lower incidence of uveitis. The risk of uveitis and blindness decreased as BD diagnosis ages increased.

Conclusion

In this large population-based cohort study, BD patients compared with the general population have a 10.73-fold risk of blindness in 10-years and also a substantially higher risk of diverse ocular comorbidities that pose potential threats to vision.

Electrochemical detection of uric acid in undiluted human saliva using uricase paper integrated electrodes

In this study, we introduce a uricase-immobilized paper (UOx­-paper) integrated electrochemical sensor for detection of uric acid (UA) in saliva. The UOx was immobilized on the detection zone in the wax-patterned paper substrate. This UOx-paper was integrated with a Prussian blue­-modified, screen-printed carbon electrode after electropolymerization of o-phenylenediamine to construct an electrochemical cell for small-volume (20 μL) of samples. First, we optimized the fabrication conditions of UOx-paper. Next, the amperometric response of the UOx-paper-based electrochemical UA sensor was analyzed using a known concentration of UA standard solution in artificial saliva at an applied potential of − 0.1 V (versus Ag pseudo-reference electrode). The UOx-­paper based electrochemical UA sensor showed a sensitivity of 4.9 μA·mM⁻¹ in a linear range of 50 to 1000 μM (R² = 0.998), high selectivity and good reproducibility, as well as a limit of detection of 18.7 μM (0.31 mg/dL) UA. Finally, we quantified the UA levels in undiluted saliva samples of healthy controls (n = 20) and gout patients (n = 8). The levels were correlated with those measured with conventional salivary UA enzymatic assays as well as serum UA levels. The UOx-paper-based electrochemical UA sensor is a user-friendly and convenient tool to assess salivary UA levels.

A Case of Macrophage Activation Syndrome During the Treatment of Adult-onset Still's Disease With Tocilizumab

Macrophage activation syndrome (MAS) is a fatal complication of adult-onset Still's disease (AOSD). Although anti-cytokine agents have been recommended for refractory AOSD or complicated with MAS, MAS cases have been rarely reported during anti-cytokine treatment. Herein, we describe the first AOSD case complicated with MAS during the treatment with tocilizumab in Korea. Two years after tocilizumab maintenance therapy, high fever and hypertransaminasemia recurred. MAS was diagnosed based on hyperferritinemia, elevated soluble IL-2 receptor levels, and the presence of hemophagocytic histiocytes in the bone marrow. However, she had normal white blood cell counts and acute phase reactant levels. High-dose glucocorticoid and anakinra therapies were not effective, but her disease improved with etoposide. This case shows that tocilizumab may not prevent MAS development and can modify clinical features making it challenging to diagnose. Cytotoxic therapy such as etoposide may be required in MAS cases that develop during anti-cytokine therapy.

Assessment on Treatments With Conventional Synthetic Disease-modifying Drugs Before Initiating Biologics in Patients With Rheumatoid Arthritis in Korea: A Population-based Study

Objective

To assess pre-biologic treatments with conventional synthetic disease-modifying drugs (csDMARDs) prior to biologics initiation among patients with rheumatoid arthritis (RA).

Methods

Using Korea National Health Insurance database, we examined pre-biologic treatments of RA patients on the following four items whether 1) initial methotrexate (MTX) therapy was given, 2) MTX dose was escalated up to ≥15 mg/week within 1-year post-diagnosis, 3) prednisone-equivalent glucocorticoid was used at a dose of ≤7.5 mg/day, and 4) glucocorticoid was discontinued within 6 months of treatment. Multivariable logistic regressions identified predictors of items 2) and 4) fulfillment.

Results

Among 6,986 biologics initiators with RA, 54.9% used MTX as the 1st csDMARD. Within 1-year post-diagnosis, 85.2% used MTX with half of them achieving a dose of ≥15 mg/week. The majority (75.2%) of patients used glucocorticoids initially and 64.5% were still on glucocorticoids at 6 months, mostly at a dose of ≤7.5 mg/day. csDMARD combination was observed in 85.7%. Item 2) fulfillment was associated with males, younger age, glucocorticoid, combination therapy, cyclo-oxygenase-2 inhibitors, and viral hepatitis. Item 4) fulfillment was associated with males, MTX dose of ≥15 mg/week, combination therapy, viral hepatitis, and hospitalizations.

Conclusion

RA patients in Korea were predominantly treated with MTX-based csDMARD combination plus glucocorticoids before initiating biologics, without sufficient MTX dose escalation or glucocorticoid discontinuation. Items 2) and 4) fulfillments were associated with patient age and gender, concomitant treatments, and comorbidities.

Extracellular pyruvate kinase M2 promotes osteoclastogenesis and is associated with radiographic progression in early rheumatoid arthritis

Extracellular PKM2 (exPKM2) levels have been reported to be increased in several cancers and inflammatory diseases, including rheumatoid arthritis (RA). This study aimed to investigate the association of circulating exPKM2 levels with radiographic progression in RA patients and the effect of exPKM2 on osteoclastogenesis. Plasma and synovial fluid exPKM2 levels were significantly elevated in RA patients. Plasma exPKM2 levels were correlated with RA disease activity and were an independent predictor for radiographic progression in RA patients with a disease duration of ≤ 12 months. CD14⁺ monocytes but not RA fibroblast-like synoviocytes secreted PKM2 upon stimulation with inflammatory mediators. Recombinant PKM2 (rPKM2) increased the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells and resorption pit in osteoclast precursors, dose-dependently, even in the absence of receptor activator of nuclear factor-kappa B ligand (RANKL). rPKM2 treatment upregulated the expression of dendrocyte-expressed seven transmembrane protein (DC-STAMP) and MMP-9 via the ERK pathway. Although rPKM2 did not directly bind to RAW264.7 cells, extracellular application of pyruvate, the end-product of PKM2, showed effects similar to those seen in rPKM2-induced osteoclastogenesis. These results suggest that exPKM2 is a potential regulator of RA-related joint damage and a novel biomarker for subsequent radiographic progression in patients with early-stage RA.

Association of rheumatoid arthritis and high sodium intake with major adverse cardiovascular events: a cross-sectional study from the seventh Korean National Health and Nutrition Examination Survey

OBJECTIVES

High salt intake has a harmful effect on hypertension; however, the association between major adverse cardiovascular events (MACE) and salt intake is still controversial. Rheumatoid arthritis (RA) is also characterised by excess cardiovascular risk. However, few studies have investigated the combined role of salt intake and RA in MACE in the general Korean population. Here, we evaluated this relationship among the Korean adult population.

DESIGN

Retrospective, cross-sectional.

SETTING

Population-based survey in Korea.

METHODS

This study was based on the data of the seventh Korean National Health and Nutrition Examination Survey (2016-2018). The estimated 24-hour urinary sodium excretion (24HUNa), a surrogate marker for daily sodium intake, was calculated using the Tanaka equation and was stratified into five groups (<3, 3-3.999, 4-4.999, 5-5.999 and ≥6 g/day). Finally, data from 13 464 adult participants (weighted n=90 425 888) were analysed; all analyses considered a complex sampling design. Multivariable logistic regression for MACE as primary dependent variable was performed and adjusted for potential covariates.

RESULTS

Participants with MACE had higher 24HUNa levels and RA proportion than those without MACE (p<0.001). The association of MACE with 24HUNa was J-shaped with a gradual increase from about 3 g/day. The highest 24HUNa (≥6 g/day) group was significantly associated with increased prevalence of MACE compared with the reference group (3-3.999 g/day) after adjusting for all associated covariates (OR 6.75, 95% CI 1.421 to 32.039). In the multivariate logistic regression analysis, RA (OR 2.05, 95% CI 1.283 to 3.264) and the highest 24HUNa group (OR 6.35, 95% CI 1.337 to 30.147) were significantly associated with MACE even after adjusting for baseline covariates.

CONCLUSIONS

These nationally representative data suggest that RA and extremely high sodium intake are associated with MACE in the general adult Korean population. Avoiding extremely high salt intake and considering RA as an important risk factor for MACE might help promote public cardiovascular health.

Association of Serum Biomarkers With Pulmonary Involvement of Rheumatoid Arthritis Interstitial Lung Disease: From KORAIL Cohort Baseline Data

Objective

The increase in mortality in rheumatoid arthritis (RA) patients with interstitial lung disease (ILD) is well known However, there are few studies on serum markers that can evaluate acute exacerbation or prognosis in RA-ILD patients The purpose of this study was to identify the association between biomarkers and lung lesions in patients with RA-ILD.

Methods

We analyzed 153 patients with serum samples in a prospective, multicenter cohort of Korean RA-ILD patients The serum levels of biomarkers, matrix metalloproteinase (MMP-7), surfactant protein-D (SP-D), and Krebs von den Lungen-6 (KL-6) were measured and correlated with forced vital capacity (FVC), diffusing capacity for carbon monoxide (DLCO) and the results of computed tomography (CT) CT results were interpreted semi-quantitatively according to the extent of lung lesions (grade 1, 0%∼25%; grade 2, 26%∼50%; grade 3, 51%∼75%; grade 4, 76%∼100%).

Results

MMP-7, SP-D, and KL-6 were negatively correlated with FVC (MMP-7, r=-0267, p=0001; SP-D, r=-0250, p=0002; KL-6, r=-0223, p=0006) and DLCO (MMP-7, r=-0404, p<0001; SP-D, r=-0286, p=0001; KL-6, r=-0226, p=0007) In addition, MMP-7, SP-D, and KL-6 tended to increase with higher grades of lung lesions on CT (MMP-7, p=0013; SP-D, p<0001; KL-6, p<0001).

Conclusion

MMP-7, SP-D, and KL-6 can be used to evaluate the functional and anatomical status of lung involvement in the RA-ILD patients.

Baseline disease activity influences subsequent achievement of patient acceptable symptom state in Sjögren's syndrome

OBJECTIVES

To investigate longitudinal changes of the EULAR SS Patient-Reported Index (ESSPRI) and EULAR SS Disease Activity Index (ESSDAI), and identify factors associated with patient acceptable symptom state (PASS) in patients with primary SS (pSS).

METHODS

We assessed ESSPRI, ESSDAI, clinical ESSDAI (ClinESSDAI), EULAR Sicca Score, EuroQoL 5-dimension (EQ-5D), Fatigue Severity Score, Beck Depression Inventory, and patient global assessment (PGA) for pSS, and visual analogue scale (VAS) scores for glandular and extra-glandular symptoms at baseline and follow-up. The responses to the currently available standards of care were evaluated by the PASS, the minimal clinically important improvement (MCII) of ESSPRI and ESSDAI, and a modified SS Responder Index-30 (mSSRI-30) response.

RESULTS

Among 115 patients enrolled, 102 (88.7%) completed a median 3-year follow-up. The ESSPRI, ClinESSDAI and EQ-5D levels remained stable, although the PGA and ESSDAI significantly improved (both P <0.05). Of the 102 patients, 52 (51.0%) patients achieved the PASS at the follow-up and tended to attain the ESSPRI-MCII and mSSRI-30 (both P < 0.001) more frequently than the non-PASS group. Multivariate analysis revealed that the PASS was significantly associated with baseline ESSPRI negatively [odds ratio (OR) 0.609] and ESSDAI positively (OR 1.224). When categorized using baseline ESSPRI and ESSDAI, a subgroup of low ESSPRI and high ESSDAI reached a PASS achievement rate of 79.3%.

CONCLUSION

Although longitudinal changes in ESSPRI and ClinESSDAI are stable in pSS, baseline ESSPRI and ESSDAI could provide prognostic information on the subsequent achievement of PASS, using currently available treatments. A categorization model using ESSPRI and ESSDAI may have clinical implications.

Subclinical sacroiliitis detected by abdominopelvic computed tomography in Korean patients with Crohn's disease

BACKGROUND/AIMS

Sacroiliitis is a frequent extraintestinal manifestation of inflammatory bowel diseases (IBDs). This study aimed to assess the prevalence of sacroiliitis using a validated screening tool based on abdominopelvic computed tomography (APCT) in Korean patients with Crohn's disease (CD) and examine potential associations between clinical characteristics and sacroiliitis.

METHODS

One hundred five patients with CD undergoing APCT for any indication at an IBD clinic were matched 1:1 for age and sex with 105 controls without underlying chronic illnesses. Using a validated APCT screening tool that defines sacroiliitis as either ankylosis or a total erosion score (TES) ≥ 3, all computed tomography scans were assessed by two independent, blinded radiologists. We compared the prevalence of sacroiliitis between CD patients and controls and clinical characteristics between CD patients with and without sacroiliitis.

RESULTS

The prevalence of sacroiliitis was significantly higher in CD patients than in controls (13.3% vs. 4.8%, p = 0.030). All subjects with sacroiliitis had a TES ≥ 3, but no ankylosis. The assessment of sacroiliitis in APCT showed excellent interreader reliability (Cohen's kappa = 0.933 for presence of sacroiliitis). Sacroiliitis in CD patients was bilateral and asymptomatic. There were no significant associations between sacroiliitis and any demographic data or clinical characteristics in these patients.

CONCLUSION

The prevalence of APCT-detected sacroiliitis in CD patients was higher than that in controls, but the condition was asymptomatic. The clinical significance of asymptomatic sacroiliitis in Korean CD patients remains unclear.

Patient perspectives on biological treatments for inflammatory arthritis: A multi-center study in Korea

Objectives: The aim of this study was to evaluate the patient’s perception of the use of biological disease-modifying anti-rheumatic drugs (bDMARDs) and provide a basis for physicians to understand the patient’s perspective.

Patients and methods: Between December 2018 and June 2019, a total of 307 patients (162 males, 145 females; mean age: 48 years; range, 18 to 81 years) were included in this investigator-initiated, multi-center, observational, and cross-sectional study in six rheumatology centers. We asked patients using bDMARDs to treat rheumatoid arthritis (RA) or ankylosing spondylitis (AS) to complete a questionnaire regarding major considerations and satisfaction with bDMARDs, preferred administration route, knowledge about bDMARDs, experiences of adverse events, non-adherence, and expectations of their healthcare provider. The satisfaction of physician and clinical information on the patient's disease and treatment were also collected.

Results: Of the patients, 139 had RA and 168 had AS. Median disease duration was six years in RA and five years in AS. A total of 80.1% of the patients and 77.1% of the physicians indicated being satisfied or very satisfied with the therapeutic effect of the current bDMARD. Most patients were open to intravenous or subcutaneous injection, with the most preferred route of administration being subcutaneous (41.3%), followed by intravenous (32.0%), and oral (26.7%). The patients considered therapeutic effect to be more important than cost or convenience while choosing a bDMARD (69.3%), and most were willing to be educated about therapeutic effects (46.1%). Only 35.2% of the patients reported well and/or very well knowledge about the therapeutic effects, side effects, and administration methods of their current bDMARD, and 86.6% cited their physician as the primary source of information about biological treatment.

Conclusion: Patients value therapeutic effect more than cost or convenience while selecting a bDMARD, and consider their physicians to be the primary information source. Therefore, it is important for physicians to provide appropriate education and encourage patients to cooperate actively with treatment.

Fucoxanthin Suppresses Osteoclastogenesis via Modulation of MAP Kinase and Nrf2 Signaling

Fucoxanthin (FX), a natural carotenoid present in edible brown seaweed, is known for its therapeutic potential in various diseases, including bone disease. However, its underlying regulatory mechanisms in osteoclastogenesis remain unclear. In this study, we investigated the effect of FX on osteoclast differentiation and its regulatory signaling pathway. In vitro studies were performed using osteoclast-like RAW264.7 cells stimulated with the soluble receptor activator of nuclear factor-κB ligand or tumor necrosis factor-alpha/interleukin-6. FX treatment significantly inhibited osteoclast differentiation and bone resorption ability, and downregulated the expression of osteoclast-specific markers such as nuclear factor of activated T cells 1, dendritic cell-specific seven transmembrane protein, and matrix metallopeptidase 9. Intracellular signaling pathway analysis revealed that FX specifically decreased the activation of the extracellular signal-regulated kinase and p38 kinase, and increased the nuclear translocation of phosphonuclear factor erythroid 2-related factor 2 (Nrf2). Our results suggest that FX regulates the expression of mitogen-activated protein kinases and Nrf2. Therefore, FX is a potential therapeutic agent for osteoclast-related skeletal disorders including osteoporosis and rheumatoid arthritis.

Sex differences in clinical characteristics and their influence on clinical outcomes in an observational cohort of patients with rheumatoid arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is more prevalent in women, but sex differences remain incompletely understood. This study aimed to elucidate sex differences in clinical characteristics and their potential impact on clinical outcomes in a large Korean cohort of patients with RA.

METHODS

In total, 5376 RA patients from the KORean Observational study Network for Arthritis (KORONA) database were examined at baseline and for 3 consecutive years using the disease activity score 28 (DAS28), health assessment questionnaire (HAQ), and patient-reported outcomes (PROs). Within a subgroup with active disease (DAS28≥3.2) at baseline, sex impacts on clinical outcome during follow-up were analyzed using generalized estimating equation (GEE) models. The factors related to achieving clinical remission were analyzed using Cox-proportional hazard regression.

RESULTS

At baseline, women (n=4574) were younger and had more erosive disease and longer disease duration than men (n=802) with higher scores in DAS28, HAQ, and PROs. The prevalence of interstitial lung disease, cardiovascular disease, and diabetes in men was higher than that of women. In a RA subgroup with active disease at baseline, GEE analyses demonstrated that women RA significantly influenced the rate of change of DAS28 over time. In that group, men are associated with achieving DAS28 sustained remission and point remission.

CONCLUSIONS

Women with RA in Korea report higher levels of disease activity and PROs compared to men, whereas most comorbidities were more prevalent in men. The longitudinal change in disease activity and the rate of achieving clinical remission were found to be worse in women with RA.

Risk prediction model in rheumatoid arthritis-associated interstitial lung disease

BACKGROUND AND OBJECTIVE

RA-ILD has a variable clinical course, and its prognosis is difficult to predict. Moreover, risk prediction models for prognosis remain undefined.

METHODS

The prediction model was developed using retrospective data from 153 patients with RA-ILD and validated in an independent RA-ILD cohort (n = 149). Candidate variables for the prediction models were screened using a multivariate Cox proportional hazard model. C-statistics were calculated to assess and compare the predictive ability of each model.

RESULTS

In the derivation cohort, the median follow-up period was 54 months, and 38.6% of the subjects exhibited a UIP pattern on HRCT imaging. In multivariate Cox analysis, old age (≥60 years, HR: 2.063), high fibrosis score (≥20% of the total lung extent, HR: 4.585), a UIP pattern (HR: 1.899) and emphysema (HR: 2.596) on HRCT were significantly poor prognostic factors and included in the final model. The prediction model demonstrated good performance in the prediction of 5-year mortality (C-index: 0.780, P < 0.001); furthermore, patients at risk were divided into three groups with 1-year mortality rates of 0%, 5.1% and 24.1%, respectively. Predicted and observed mortalities at 1, 2 and 3 years were similar in the derivation cohort, and the prediction model was also effective in predicting prognosis of the validation cohort (C-index: 0.638, P < 0.001).

CONCLUSION

Our results suggest that a risk prediction model based on HRCT variables could be useful for patients with RA-ILD.

Risk factors associated with initiation of a biologic disease modifying anti-rheumatic drug in patients with rheumatoid arthritis: A nested case-control study on 34,925 patients

OBJECTIVE

To identify risk factors of biological disease-modifying anti-rheumatic drugs (bDMARDs) initiation in patients with rheumatoid arthritis (RA).

METHODS

Using the 2002-2016 Korea National Health Insurance database, we conducted a nested case-control study on seropositive RA patients. Cases (bDMARD users) and controls (users of conventional synthetic DMARDs only) were 1:4 matched on the calendar year/month of RA diagnosis and index dates (bDMARD initiation dates). Potential risk factors from two time periods, 1-year post-RA-diagnosis and 1-year pre-index, were separately assessed on the association with bDMARD initiation by conditional logistic regression analyses.

RESULTS

The study included 6985 cases and 27,940 controls. Older age, female gender, use of methotrexate (MTX), leflunomide, or tacrolimus as a first csDMARD, higher initial MTX dose, and initial csDMARD combination during 1-year post-diagnosis were negatively associated with later bDMARD initiation, while use of sulfasalazine as a first csDMARD, corticosteroid therapy, and higher maximal MTX dose were positively associated. Among covariates from 1-year period before bDMARD initiation, use of leflunomide, sulfasalazine, or tacrolimus, parenteral MTX, higher maximal MTX dose, corticosteroid, and csDMARD combination were positively associated with subsequent bDMARD initiation. Effects of comorbidities on bDMARD initiation were heterogenous across involved systems.

CONCLUSION

In this population-based nationwide study, we identified period-specific risk factors of bDMARD initiation among RA patients in Korea. Overall, initial aggressive RA treatment after diagnosis was associated with less use of later bDMARD, while highly intensive therapy observed just before bDMARD initiation rather reflects refractory nature of RA during this period, and did not prevent bDMARD use.

Methotrexate-loaded multifunctional nanoparticles with near-infrared irradiation for the treatment of rheumatoid arthritis

Backgrounds

Despite the advances of rheumatoid arthritis (RA) therapeutics, several patients do not receive adequate treatment due to the toxicity and/or insufficient response of drugs. The aim of this study is to design photothermally controlled drug release from multifunctional nanoparticles (MNPs) at a near-infrared (NIR) irradiated site to improve therapeutic efficacy for RA and reduce side effects.

Methods

Au film was deposited onto methotrexate (MTX)-loaded poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PLGA) nanoparticles, resulting in MTX-loaded MNPs. The synergistic effects of MTX-loaded MNPs with NIR irradiation were investigated using RA fibroblast-like synoviocytes (FLSs) and collagen-induced arthritis (CIA) mice.

Results

Upon NIR irradiation, NIR resonance of the Au half-shell generated heat locally, accelerating MTX release from PLGA nanoparticles. In vivo NIR images of MTX-loaded MNPs indicated effective delivery of the MNPs to the inflamed joints. Moreover, in collagen-induced arthritis mice, MTX-loaded MNPs containing 1/1400 of MTX solution (repeated-dose administration) had therapeutic effects comparable to conventional treatment with MTX solution. In vitro experiments showed higher therapeutic efficacy of MTX-loaded MNPs with NIR irradiation than that of chemotherapy alone.

Conclusions

A combination therapy of MTX-loaded MNP and NIR irradiation showed durable and good treatment efficacy for the suppression of arthritis in a single administration of small dose of MTX. Our results demonstrate that the treatment modality using drug-loaded MNP with NIR irradiation may be a promising therapeutic strategy for the treatment of RA and allow in vivo NIR optical imaging.

Autoantibody Biomarkers in Rheumatic Diseases

Autoantibodies encountered in patients with systemic rheumatic diseases bear clinical significance as a biomarker to help or predict diagnosis, clinical phenotypes, prognosis, and treatment decision-making. Furthermore, evidence has accumulated regarding the active involvement of disease-specific or disease-associated autoantibodies in the pathogenic process beyond simple association with the disease, and such knowledge has become essential for us to better understand the clinical value of autoantibodies as a biomarker. This review will focus on the current update on the autoantibodies of four rheumatic diseases (rheumatoid arthritis, myositis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody associated vasculitis) where there has been a tremendous progress in our understanding on their biological effects and clinical use.

Clinical features and risk factors for gout attacks during anti-tuberculosis treatment: A case-control study in South Korea

AIM

This study aimed to investigate the clinical features and risk factors of gout attacks during anti-tuberculosis (TB) treatment in South Korea.

METHOD

We investigated the clinical characteristics of 49 patients who suffered from gout attacks while taking anti-TB medications. Among them, 25 TB patients having newly developed gout attacks without prior history of gout were set to the gout group. Seventy-five age- and sex-matched TB patients without gout attacks during anti-TB therapy were randomly selected as the control group. The demographics, clinical features, and laboratory findings between the two groups were compared to establish risk factors of gout attack during anti-TB treatment.

RESULTS

The gout patients had a mean age of 67.7 ± 13.2 years and 39 patients (79.6%) were male. Approximately half of the patients experienced an attack within 2 months of treatment initiation. The attacks typically involved lower extremity joints (87.8%). The serum uric acid (SUA) levels were significantly elevated at 2 and 6 months after starting anti-TB medication compared with those at baseline. In the case-control study, the factors associated with gout attack were higher body mass index (BMI), higher pre-treatment SUA levels, dyslipidemia, and reduced renal function. In the multivariate model, higher BMI, chronic kidney disease (CKD), and pre-treatment hyperuricemia (SUA ≥ 6.8 mg/dL) were independent risk factors of gout attack while taking anti-TB medication.

CONCLUSIONS

Patients with high BMI, CKD, and pre-treatment hyperuricemia are at a higher risk of gout attack during TB treatment.

Impact of sleep quality on clinical features of primary Sjögren's syndrome

BACKGROUND/AIMS

This study aimed to investigate the inf luence of poor sleep quality on clinical features of primary Sjögren's syndrome (pSS).

METHODS

Sleep quality was cross-sectionally assessed using the Pittsburgh Sleep Quality Index (PSQI), and demographic, clinical, and laboratory data were collected from 115 Korean patients with pSS. The patients completed questionnaires on the European League Against Rheumatism (EULAR) SS Patient Reported Index (ESSPRI), quality of life (EuroQOL five dimensions questionnaire [EQ-5D]), fatigue (fatigue severity score [FSS]), and depression (Beck Depression Inventory [BDI] II]). Symptoms and patient global assessment (PGA) were evaluated with a 100-mm visual analogue scale (VAS). The EULAR sicca score (ESS), ESSPRI, and EULAR SS Disease Activity Index (ESSDAI) were calculated at study enrollment.

RESULTS

Fifty-three patients (46.1%) had poor sleep quality and 32.4% of 71 patients without depression were poor sleepers. Poor sleepers had a significantly lower EQ-5D or ESSDAI and a significantly higher FSS, BDI-II, PGA, ESS, ESSPRI, or VAS scores for extra-glandular symptoms than good sleepers. Neutrophil and lymphocyte counts were significantly higher and immunoglobulin G levels tended to decrease in poor sleepers. Additionally, PSQI was negatively correlated with EQ-5D and ESSDAI and positively with ESS, FSS, BDI-II, PGA, VAS scores for their symptoms, and ESSPRI. Multivariate analysis revealed that poor sleep quality remained the independent determinants of the unsatisfactory symptom state (ESSPRI ≥ 5).

CONCLUSION

Our results showed that poor sleep quality could significantly affect the patient-oriented outcomes and physician-reported activity index of pSS patients through the various effects of sleep quality on the psychological or somatic symptoms and the immune system.

Association between socioeconomic status and comorbidities among patients with rheumatoid arthritis: results of a nationwide cross-sectional survey

Objectives

We examined the association between socioeconomic status (SES) and comorbidity distribution among patients with RA.

Methods

Information on comprehensive health status of 1088 RA patients (weighted n = 612 303) was obtained from the 2007–2015 Korea National Health and Nutrition Examination Survey database. SES components were household equivalence income, education and area of residence. To minimize confounding by age, patients were stratified by median age (63 years). Age-adjusted odds ratio (OR) with 95% confidence interval (95% CI) was estimated, comparing weighted prevalence of individual comorbidities between low and high SES groups in each age stratum.

Results

Among RA patients aged <63 years (mean 49 years, 70% female), we observed age-adjusted associations of depression (OR 2.13, 95% CI 1.01, 4.53), depressive mood (OR 2.68, 95% CI 1.54, 4.65), suicide ideation (OR 3.01, 95% CI 1.79, 5.07), diabetes (OR 3.09, 95%CI 1.31, 7.29), obesity (OR 2.04, 95% CI 1.30, 3.20), hypertriglyceridemia (OR 2.36, 95% CI 1.28, 4.34) and osteoarthritis (OR 2.12, 95% CI 1.13, 3.99) with low income, of suicide ideation with low education (OR 2.25, 95% CI 1.14, 4.44), but no association of any comorbidities with area of residence. Unhealthy behavior patterns were comparable between low- and high-income groups but patients with low income reported a numerically higher rate of failed access to necessary healthcare services. We did not find any association between SES and comorbidities among those aged ⩾63 years (mean 72 years, 83% female).

Conclusion

Among Korean RA patients aged <63 years, socioeconomic inequalities of multiple comorbidities in mental, cardiometabolic and musculoskeletal systems were found.

Novel susceptibility alleles in HLA region for myositis and myositis specific autoantibodies in Korean patients

OBJECTIVES

HLA genes are a major genetic risk factor for myositis and myositis specific antibodies (MSAs), exhibiting unique HLA backgrounds for myositis in different ethnic groups. This is the first large scale Korean study to genotype the HLA-DRB1 and -DPB1 alleles and to examine their association with myositis and MSAs.

METHODS

HLA-DRB1 and HLA-DPB1 alleles and MSAs were examined in 179 patients with dermatomyositis (DM, n = 129) or polymyositis (PM, n = 50) and healthy controls (n = 800 for HLA-DRB1, n = 548 for HLA-DPB1). Associations between individual HLA alleles and myositis/MSA were examined. Bonferroni correction was applied for multiple testing comparing patients and controls.

RESULTS

A total of 33 HLA-DRB1 and 24 HLA-DPB1 alleles were genotyped in patients and controls. MSAs were found in 67.0% of patients. Anti-MDA5 (26.8%) and anti-aminoacyl-tRNA synthetase antibodies (15.6%) were most common, followed by anti-Mi2 (9.5%) and anti-TIF1γ antibodies (8.9%). HLA-DRB1*12:02 and HLA-DRB1*14:03 were associated with DM and PM, respectively. HLA-DRB1*12:02 was associated with anti-MDA5, HLA-DRB1*08:03 with anti-ARS, HLA-DRB1*14:03 with anti-SRP, and HLA-DRB1*07:01 with anti-Mi2 antibodies. Although HLA-DRB1*13:01 was associated with anti-TIF1γ antibodies, the frequency of HLA-DRB1*13:01 was rare. HLA-DPB1*02:01 was negatively associated with myositis and PM while HLA-DPB1*17:01 was associated with anti-Mi2 positive DM.

CONCLUSIONS

Unique immunogenetic background was observed for Korean patients with myositis. Novel myositis susceptibility alleles, HLA-DRB1*12:02 and HLA-DRB1*14:03, were identified, together with MSA-associated HLA alleles unique to Korean patients with myositis.

Serum KL-6 levels reflect the severity of interstitial lung disease associated with connective tissue disease

Background

Biomarkers have been actively investigated to supplement functional and imaging modalities to predict the severity, therapeutic responsiveness, and progression of connective tissue disease-associated interstitial lung disease (CTD-ILD). This study aimed to evaluate Krebs von den Lungen 6 (KL-6) as a potential biomarker reflecting the severity of CTD-ILD as assessed through computed tomography (CT) and pulmonary function test (PFT) parameters.

Methods

This retrospective study included 549 Korean patients with rheumatoid arthritis, systemic sclerosis, inflammatory myositis, and other CTDs with or without concurrent ILD. Serum KL-6 concentration (U/mL) was measured using the latex-enhanced immunoturbidimetric assay method. CT and PFT results were collected within 1 year of serum collection. A semiquantitative grade of ILD extent was evaluated through CT scan (grade 1, 0–25%; grade 2, 26–50%; grade 3, 51–75%; grade 4, 76–100%).

Results

CTD-ILD patients (n = 165) had elevated serum KL-6 levels compared to CTD patients without ILD (n = 384) (p < 0.001), and those findings were preserved after adjusting for age, sex, and CTD type. The semiquantitative grade of ILD on CT scan was significantly proportional to the KL-6 level, and the optimal cut-off KL-6 value effectively differentiated each ILD grade. The percent diffusing capacity of the lung for carbon monoxide (DLCO) (p < 0.001) and forced vital capacity (FVC) (p < 0.001) parameters had a moderate, negative correlation with the KL-6 level.

Conclusion

Serum KL-6 levels were increased in CTD-ILD patients and had a positive correlation with CT grade and a negative correlation with FVC and DLCO. Serum KL-6 levels may reflect CTD-ILD severity.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1835-9) contains supplementary material, which is available to authorized users.

Circulating Semaphorin 4D as a Marker for Predicting Radiographic Progression in Patients with Rheumatoid Arthritis

Semaphorin 3A (Sema3A) and semaphorin 4D (Sema4D) are molecules which regulate immune responses as well as bone remodeling process. The aim of this study was to evaluate the serum levels of Sema3A and Sema4D and to investigate their clinical significance in rheumatoid arthritis (RA). The serum levels of Sema3A and Sema4D were measured in 130 patients with RA and 65 sex- and age-matched healthy individuals. Circulating levels of biomarkers of RA-related inflammation and bone turnover such as tumor necrosis factor- (TNF-) α, interleukin- (IL-) 6, IL-22, IL-34, osteopontin, Dkk-1, and sclerostin were also measured. Disease activity was determined by the 28-joint disease activity score (DAS28), and radiographic joint damage was assessed by the modified Sharp van der Heijde score (SHS). The serum levels of Sema3A were significantly higher in patients with RA than those in healthy controls (p < 0.001), whereas serum4D levels did not differ between the two groups. The levels of Sema4D showed a positive correlation with C-reactive protein (p = 0.001) and IL-6 (p < 0.001) levels, whereas the levels of Sema3A showed a negative correlation with Dkk-1 (p = 0.007) and TNF-α (p = 0.001). Even though Sema3A and Sema4D levels were comparable between RA patients with DAS28> 3.2 and with DAS28 ≤ 3.2, RA patients with radiographic progression (ΔSHS change/year ≥ 1) had significantly higher baseline levels of Sema4D than those without progression (p = 0.029). Additionally, when RA patients were divided into 3 groups using tertiles of Sema4D levels, the percentage of progressors was significantly increased (p = 0.045). In multivariate logistic regression analysis, serum Sema4D levels were an independent risk factor for radiographic progression. Our results suggest that the baseline levels of Sema4D might be a useful marker to identify RA patients with subsequent radiographic progression and that Sema4D may be an active mediator involved in RA-induced joint damage.

Impact of Tumor Necrosis Factor Inhibitor Versus Nonsteroidal Antiinflammatory Drug Treatment on Radiographic Progression in Early Ankylosing Spondylitis: Its Relationship to Inflammation Control During Treatment

Objective

To investigate the impact of tumor necrosis factor inhibitor (TNFi) treatment and inflammation control on radiographic progression in early ankylosing spondylitis (AS) over 4 years.

Methods

We included a total of 215 patients with early AS (symptom duration <10 years) treated with TNFi (the TNFi group; n = 135) or with nonsteroidal antiinflammatory drugs (NSAIDs) (the control group; n = 80). Two blinded readers assessed radiographic progression using the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). Inflammation control was inferred from C‐reactive protein (CRP) levels time‐averaged between 2 radiologic assessments. Linear mixed modeling was used to estimate mSASSS changes over radiographic intervals as well as the impact of clinical factors on outcomes.

Results

The TNFi group had longer disease duration, a higher baseline CRP level, and a higher Bath Ankylosing Spondylitis Disease Activity Index than did controls. The time‐averaged CRP level over radiographic intervals was lower with TNFi treatment than with NSAID treatment (mean ± SD 0.27 ± 0.30 mg/dl versus 0.61 ± 0.68 mg/dl; P < 0.001). Overall, mean ± SD mSASSS change over the 2‐year interval was 1.30 ± 2.97 units. In the multivariable model adjusted for age, smoking status, baseline CRP level, and the presence of syndesmophytes at baseline, the TNFi group showed less mSASSS change over the 2‐year interval (β = −0.90 [95% confidence interval {95% CI} −1.51, −0.29]). However, when a time‐averaged CRP level was additionally included, it significantly influenced the mSASSS change (β = 1.02 [95% CI 0.32, 1.71]), decreasing the estimated group difference (β = −0.52 [95% CI −1.17, 0.14]). NSAID indices of both groups were not associated with either time‐averaged CRP levels or mSASSS changes.

Conclusion

Effective suppression of inflammation by TNFi treatment decreases radiographic progression in early AS.

Impact of temporary methotrexate discontinuation for 2 weeks on immunogenicity of seasonal influenza vaccination in patients with rheumatoid arthritis: a randomised clinical trial

OBJECTIVE

To determine whether a 2-week methotrexate (MTX) discontinuation after vaccination improves the efficacy of seasonal influenza vaccination in patients with rheumatoid arthritis (RA).

METHODS

In this prospective randomised parallel-group multicentre study, patients with RA on stable dose of MTX were randomly assigned at a ratio of 1:1 to continue MTX or to hold MTX for 2 weeks after 2016-2017 quadrivalent seasonal influenza vaccine containing H1N1, H3N2, B-Yamagata and B-Victoria. The primary outcome was frequency of satisfactory vaccine response, defined as greater than or equal to fourfold increase of haemagglutination inhibition (HI) antibody titre at 4 weeks after vaccination against ≥2 of four vaccine strains. Secondary endpoints included seroprotection (ie, HI titre ≥1:40) rate, fold change in antibody titres.

RESULTS

The modified intention-to-treat population included 156 patients in the MTX-continue group and 160 patients in the MTX-hold group. More patients in MTX-hold group achieved satisfactory vaccine response than the MTX-continue group (75.5% vs 54.5%, p<0.001). Seroprotection rate was higher in the MTX-hold group than the MTX-continue group for all four antigens (H1N1: difference 10.7%, 95% CI 2.0% to 19.3%; H3N2: difference 15.9%, 95% CI 5.9% to 26.0%; B-Yamagata: difference13.7%, 95% CI 5.2% to 22.4%; B-Victoria: difference 14.7%, 95% CI 4.5% to 25.0%). The MTX-hold group showed higher fold increase in their antibody titres against all four influenza antigens (all p<0.05). Change in disease activity was similar between groups.

CONCLUSIONS

A temporary MTX discontinuation for 2 weeks after vaccination improves the immunogenicity of seasonal influenza vaccination in patients with RA without increasing RA disease activity.

TRIAL REGISTRATION

NCT02897011.

Increased expression of interferon-λ in minor salivary glands of patients with primary Sjögren's syndrome and its synergic effect with interferon-α on salivary gland epithelial cells

OBJECTIVES

To investigate the expressions of interferon (IFN)-λs and their receptor, IL28RA, in minor salivary glands (MSG) of pSS patients and their effects on the salivary gland cells.

METHODS

The expressions of IFN-λs and IL28RA were evaluated in MSG by immunohistochemistry in 15 patients with pSS and in 5 patients with non-SS sicca. Poly(I:C)-induced IL-28A and IL-29 expressions were determined in immortalized human salivary gland acinar (NS-SV-AC) and ductal (NS-SV-DC) cell lines. We assessed the effect of IFN-λs on the expressions of typical interferon-inducible genes, B-cell activating factor (BAFF) and CXCL10, and the synergistic effect of IL-29 and type I or II IFN on their expressions. The serum IL-29 levels were measured in 44 patients with pSS and 22 healthy controls.

RESULTS

IFN-λs expression was significantly higher in MSG from pSS than from non-SS sicca controls. Poly(I:C) treatment led to the induction of IL-28A and IL-29 in the salivary gland cell lines. In the NS-SV-DC cells, IFN-λ significantly increased the levels of BAFF and CXCL10 in a time and dose-dependent manner. Moreover, there was a synergistic effect between IL-29 and IFN-α in the induction of BAFF and CXCL10 expressions by prolonged STAT1 phosphorylation. However, the serum IL-29 levels were not significantly higher in pSS patients than in healthy controls.

CONCLUSIONS

Our results suggest the possibility for IFN-λ to play a role by participating local inflammation in the salivary glands of pSS through direct and indirect regulations of the expressions of BAFF and CXCL10 in salivary gland epithelium.

Behçet's disease risk association fine-mapped on the IL23R-IL12RB2 intergenic region in Koreans

Background

Behçet’s disease (BD) susceptibility had been associated with single-nucleotide polymorphisms (SNPs) in IL23R–IL12RB2, IL10, STAT4, or ERAP1 locus in Japanese, Turkish, Chinese, and other populations, but not in a Korean genome-wide association study (GWAS). We aimed to fine-map BD risk association of these four loci using extensive imputation and additional genotyping for replication.

Methods

In the discovery phase, 369 patients with BD enrolled in the previous Korean GWAS and 2000 controls retrieved from a population-based cohort of healthy Koreans were imputed for their genotypes of all SNPs in the four loci using the Asian data of the 1000 Genomes Project as reference. For genotype imputation of ERAP1 SNPs, the adjacent ERAP2 SNPs were also covered. For the 10 most significantly associated SNPs (8 imputed and 2 GWAS-genotyped), an additional 84 patients with BD and 283 healthy controls were genotyped for replication. The results from the discovery and replication phases were pooled for meta-analysis using the Mantel-Haenszel test to estimate the odds ratio (OR) and 95% confidence interval (CI).

Results

An IL23R–IL12RB2 intergenic SNP rs1495965 was significantly associated with BD risk (OR (95% CI) = 1.5 (1.3, 1.7), P = 2.5 × 10⁻⁷) in the pooled meta-analysis of the discovery (1.4 (1.2, 1.7), P = 4.9 × 10⁻⁷) and replication (1.9 (1.3, 2.6), P = 6.0 × 10⁻⁴) phases. BD risk association was fine-mapped on the intergenic region rather than the two flanking genes, as rs1495966 and rs4655535, almost perfectly correlated with rs1495965 (r² = 0.99), were also located in the same intergenic region. Consistent with previous reports, the P values tended to be lower within IL23R than IL12RB2. On the other hand, several IL10 SNPs were suggested for association in the discovery phase but all failed in the replication phase. No SNP in ERAP1–ERAP2 and STAT4 was suggested even in the discovery phase.

Conclusions

BD susceptibility association was fine-mapped on the intergenic region between IL23R and IL12RB2 as marked by three correlated SNPs, rs1495965, rs1495966, and rs4655535.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1435-5) contains supplementary material, which is available to authorized users.

Delta neutrophil index contributes to the differential diagnosis between acute gout attack and cellulitis within 24 hours after hospitalization

Objective

An acute gout attack is often misdiagnosed as cellulitis. Differentiating these two diseases is crucial when deciding treatment strategies. Delta neutrophil index (DNI) represents the difference between leucocyte subfractions that corresponds to the fraction of immature granulocytes and can predict the bacterial infection burden. The aim of this study was to evaluate the potential of DNI as a predictive marker for differentiating an acute gout attack and cellulitis.

Methods

We reviewed medical records of 184 patients with an acute gout attack and 183 patients with lower limb cellulitis. DNI was automatically determined by the ADVIA 2120 electronic cell analyser. We used logistic regression to determine independent variables for predicting cellulitis among clinical and laboratory markers. We performed a subgroup analysis among patients without MSU crystal confirmation and among patients with normouricaemia.

Results

Patients with an acute gout attack had lower values of DNI than those with cellulitis (0.6 vs 2.8%; P < 0.001). These results were consistent in patients without MSU confirmation and in patients with normouricaemia (0.5 vs 2.8 and 0.7 vs 2.6%, respectively; P < 0.001 for both). A cut-off value of 1.7% was determined to predict cellulitis. Multivariate analysis showed that DNI was the only independent predictive value for cellulitis (odds ratio 9.699). Similar results were found in patients without MSU confirmation and in patients with normouricaemia (odds ratio 18.763 and 5.215, respectively).

Conclusion

This study showed that DNI was an effective independent marker to differentiate between an acute gout attack and cellulitis at the crucial early phase irrespective of MSU crystal confirmation or serum uric acid concentration.