Comparative effectiveness of tofacitinib and tumour necrosis factor inhibitors in patients with rheumatoid arthritis in real-world practice: a prospective observational study.

OBJECTIVE: To assess the effectiveness of tofacitinib vs tumour necrosis factor inhibitors (TNFi) in Korean patients with rheumatoid arthritis (RA). METHODS: The study used data from a single academic referral hospital's registries of biologic disease-modifying anti-rheumatic drugs (bDMARDs) and tofacitinib and examined remission rates based on the disease activity score (DAS)28-erythrocyte sedimentation rate (ESR) after 12 months. Multivariable logistic regression analysis was used to estimate the odds ratio (OR) for achieving remission with tofacitinib compared with TNFi, adjusting for potential confounders. RESULTS: This analysis included 665 patients (200 on tofacitinib and 455 on TNFi) who were followed up for at least 12 months. Of these, 96 patients in the tofacitinib group (48.0%) and 409 patients in the TNFi group (89.9%) were treatment-naïve to bDMARDs. Intention-to-treat analysis revealed no significant difference in the remission rates between the two groups (18.0% vs 19.6%, p = 0.640). Multivariable analysis demonstrated comparable remission rates with tofacitinib and TNFi (OR 1.204, 95% confidence interval [CI] 0.720-2.013). In the subpopulation naïve to JAKi and bDMARD, tofacitinib showed better remission rates than TNFi (OR 1.867, 95% CI 1.033-3.377). Tofacitinib had more adverse events (AEs) but similar rates of serious AEs (SAEs) to TNFi. CONCLUSION: In real-world settings, there was no significant difference in remission rates at 12 months between the tofacitinib and TNFi groups. In terms of safety, tofacitinib exhibited a higher incidence of AEs compared with TNFi, while the occurrence of SAEs was comparable between the groups. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT02602704.

Cost-of-illness changes before and after the diagnosis of systemic lupus erythematosus: a nationwide, population-based observational study in Korea.

OBJECTIVES: To estimate the direct healthcare cost progression from before to after systemic lupus erythematosus (SLE) diagnosis and to compare healthcare costs by disease severity. METHODS: Patients with incident SLE diagnosed between 2008 and 2018 were identified from the Korean National Health Insurance database. Annual direct healthcare costs for 5 years before and after SLE were estimated and compared with those of age-, sex-, and calendar month-matched (1:4) controls, without SLE. Direct healthcare costs were compared by disease severity of SLE using regression analysis. RESULTS: Among 11 173 patients with SLE and 45 500 subjects without SLE, annual direct healthcare costs per person increased in the year before SLE diagnosis and peaked in the first year after diagnosis. They were 7.7-fold greater in the SLE patients than in the subjects without SLE ($5,871 vs $759). Severe SLE was associated with 3.284-fold (95% CI 3.075-3.507) higher annual costs than mild SLE during the year after diagnosis. Older age (age 60-79 years), lupus nephritis, interstitial lung diseases, and comorbidities such as avascular necrosis and chronic kidney disease were associated with higher annual direct healthcare costs (times [95% CI]) in the first year after diagnosis; aged 60-69, 1.119 [1.034-1.211], aged 70-79, 1.470 [1.342-1.611], 1.794 [1.711-1.881], 1.435 [1.258-1.638], 6.208 [4.541-8.487], and 1.858 [1.673-2.064], respectively. CONCLUSION: Patients with SLE incurred significantly high direct healthcare costs than subjects without SLE during the first year after diagnosis. Disease severity, older age, major organ involvements and comorbidities were associated with increased healthcare costs.

Transcriptomic network analysis reveals key drivers of response to anti-TNF biologics in patients with rheumatoid arthritis.

OBJECTIVE: Anti-TNF biologics have been widely used to ameliorate disease activity in patients with rheumatoid arthritis (RA). However, a large fraction of patients show a poor response to these agents. Moreover, no clinically applicable predictive biomarkers have been established. This study aimed to identify response-associated biomarkers using longitudinal transcriptomic data in two independent RA cohorts. METHODS: RNA sequencing data from peripheral blood cell samples of Korean and Caucasian RA cohorts before and after initial treatment with anti-TNF biologics were analyzed to assess treatment-induced expression changes that differed between highly reliable excellent and null responders. Weighted correlation network, immune cell composition, and key driver analyses were performed to understand response-associated transcriptomic networks and cell types and their correlation with disease activity indices. RESULTS: In total, 305 response-associated genes showed significantly different treatment-induced expression changes between excellent and null responders. Co-expression network construction and subsequent key driver analysis revealed that 41 response-associated genes played a crucial role as key drivers of transcriptomic alteration in four response-associated networks involved in various immune pathways: type I interferon signalling, myeloid leucocyte activation, B cell activation, and NK cell/lymphocyte-mediated cytotoxicity. Transcriptomic response scores that we developed to estimate the individual-level degree of expression changes in the response-associated key driver genes were significantly correlated with the changes in clinical indices in independent patients with moderate or ambiguous response outcomes. CONCLUSIONS: This study provides response-specific treatment-induced transcriptomic signatures by comparing the transcriptomic landscape between patients with excellent and null responses to anti-TNF drugs at both gene and network levels.

Korean LupusPRO: Cross-Cultural validation study for systemic lupus erythematosus.

OBJECTIVE: To establish the reliability and validity of the Korean version of LupusPRO version 1.7 (v1.7) for systemic lupus erythematosus (SLE) patients. METHODS: LupusPRO v1.7 was translated into Korean, followed by pretesting among five native Korean speakers. We administered the LupusPRO v1.7 survey to five SLE patients and made minor changes to clarify the language. Then, 133 SLE patients participated in the validation procedure. In each domain, the internal consistency reliability (ICR) and test-retest reliability (TRR) were assessed using Cronbach's alpha and the intra-class correlation coefficient (ICC), respectively. Criterion validity was evaluated using Spearman's correlation coefficient with the other measures such as SF-36, EQ-5D VAS, and SELENA-SLEDAI PGA. Construct validity was assessed by confirmatory factor analysis (CFA) using the unweighted least square estimation method. RESULTS: The mean age of the 133 patients was 36.14 years, and 97% of them were women. Analysis of 130 returned questionnaires revealed that most ICRs of the Korean LupusPRO v1.7 domains were acceptable, with Cronbach's alphas in the range of 0.579-0.949, and most TRRs were good with ICCs from 0.582 to 0.851. Criterion validities presented significant correlations between the LupusPRO v1.7 and other measures validated. In the analysis of the CFA model, the goodness of fit indices demonstrated an acceptable fit. Factor loadings for most individual items were between 0.548 and 0.985. The average variance extracted (AVE) and composite reliability (CR) of most domains were greater than 0.5 and 0.7, respectively, demonstrating acceptable convergent and discriminant validities. CONCLUSIONS: The Korean version of LupusPRO v.17 had acceptable reliability and validity.

COX-2 Inhibitor Use as an Early Treatment Option for Knee Osteoarthritis Patients in Korea: A Population-Based Cross-Sectional Study.

BACKGROUND: To investigate the use of cyclooxygenase-2 (COX-2) inhibitors as an initial drug treatment for knee osteoarthritis (OA) patients. METHODS: From 2013 to 2015, patients with knee OA were identified from the Korean nationwide claims database. Among them, we extracted incident cases of knee OA to identify the initial drug treatment. Trends in the use of non-steroid anti-inflammatory drugs (NSAIDs) including COX-2 inhibitors were analyzed during the first year after their diagnosis. Associated factors for COX-2 inhibitor use were examined using a multivariate logistic regression model. RESULTS: We identified 2,857,999 incident knee OA patients (955,259 in 2013, 981,314 in 2014, and 921,426 in 2015). The mean ± standard deviation age of patients was 64.2 ± 9.8 years. The frequency of COX-2 inhibitor use as initial treatment increased from 3.5% in 2013 to 7.2% in 2015 (P < 0.01). In patients taking the medication regularly for one year after diagnosis (medication possession ratio ≥ 50%), COX-2 inhibitor use also rapidly increased from 5.5% in 2013 to 11.1% in 2015 (P < 0.01). However, the frequencies of non-selective NSAID and analgesic use did not decrease remarkably. Factors associated with patients using COX-2 inhibitors on initial drug treatment were older age (odds ratio [OR], 1.08), female (OR, 1.24), and comorbidity (OR, 1.03). Type of institution, physician speciality, and insurance type of patients were also associated. CONCLUSION: In Korea, COX-2 inhibitors have rapidly increased as an initial treatment for knee OA patients, but it has not appeared to reduce the use of non-selective NSAIDs and analgesics.

Prevalence, incidence and cause-specific mortality of rheumatoid arthritis-associated interstitial lung disease among older rheumatoid arthritis patients.

OBJECTIVE: We aimed to investigate the prevalence, incidence and cause-specific mortality of RA-associated interstitial lung disease (RA-ILD) among older US patients with RA. METHODS: We performed a nationwide cohort study using Medicare claims data (parts A, B and D for 2008-2017). RA was identified with a validated algorithm using RA diagnosis codes and DMARD prescription. RA-ILD was identified with a validated algorithm using ILD diagnosis codes by a rheumatologist/pulmonologist. RA-ILD was categorized as prevalent or incident relative to the initial RA observation (baseline/index date). We compared the total mortality of RA-ILD to RA without ILD using multivariable Cox regression, adjusting for baseline covariates. For cause-specific mortality, Fine and Gray subdistribution hazard ratios (sdHRs) were estimated to handle competing risks of alternative mortality causes. RESULTS: Among 509 787 RA patients (mean age 72.6 years, 76.2% female), 10 306 (2.0%) had prevalent RA-ILD at baseline. After baseline, 13 372 (2.6%) developed RA-ILD during 1 873 127 person-years of follow-up (median 3.0 years/person). During follow-up, 38.7% of RA-ILD patients died compared with 20.7% of RA patients without ILD. After multivariable adjustment, RA-ILD had an HR of 1.66 (95% CI 1.60, 1.72) for total mortality. Accounting for competing risk of other causes of death, RA-ILD had an sdHR of 4.39 (95% CI 4.13, 4.67) for respiratory mortality and an sdHR of 1.56 (95% CI 1.43, 1.71) for cancer mortality compared with RA without ILD. CONCLUSIONS: RA-ILD was present or developed in nearly 5% of patients in this nationwide study of older patients with RA. Compared with RA without ILD, RA-ILD was associated with excess total, respiratory and cancer mortality that was not explained by measured factors.

Validation of claims-based algorithms to identify patients with psoriasis.

PURPOSE: Accurately identifying patients with psoriasis (PsO) is crucial for generating real-world evidence on PsO disease course and treatment utilization. METHODS: We developed nine claims-based algorithms for PsO using a combination of the International Classification of Diseases (ICD)-9 codes, specialist visit, and medication dispensing using Medicare linked to electronic health records data (2013-2014) in two healthcare provider networks in Boston, Massachusetts. We calculated positive predictive value (PPV) and 95% confidence interval (CI) for each algorithm using the treating physician's diagnosis of PsO via chart review as the gold standard. Among the confirmed PsO cases, we assessed their PsO disease activity. RESULTS: The nine claims-based algorithms identified 990 unique patient records. Of those, 918 (92.7%) with adequate information were reviewed. The PPV of the algorithms ranged from 65.1 to 82.9%. An algorithm defined as ≥1 ICD-9 diagnosis code for PsO and ≥1 prescription claim for topical vitamin D agents showed the highest PPV (82.9%). The PPV of the algorithm requiring ≥2 ICD-9 diagnosis codes and ≥1 prescription claim for PsO treatment excluding topical steroids was 81.1% but higher (82.5%) when ≥1 diagnosis was from a dermatologist. Among 411 PsO patients with adequate information on PsO disease activity in EHRs, 1.5-5.8% had no disease activity, 31.3-36.8% mild, and 26.9-35.1% moderate-to-severe across the algorithms. CONCLUSIONS: Claims-based algorithms based on a combination of PsO diagnosis codes and dispensing for PsO-specific treatments had a moderate-to-high PPV. These algorithms can serve as a useful tool to identify patients with PsO in future real-world data pharmacoepidemiologic studies.

Gender differences in factors associated with low quality of life and depression in Korean patients with ankylosing spondylitis.

PURPOSE: To identify predictors of low health-related quality of life (HRQoL) and depression in ankylosing spondylitis (AS) patients with a focus on gender differences. METHODS: We conducted a cross-sectional cohort study. Both AS-related clinical data and contextual factors were obtained. HRQoL and depressive mood were assessed by EuroQol-5 dimension (EQ-5D) and the Center for Epidemiological Studies Depression Scale (CES-D), respectively. Gender-stratified multivariable logistic regression analyses were performed. RESULTS: Among 211 patients, 161 were males. Males had similar disease activity and higher radiographic damage compared with females. There was no significant difference in EQ-5D index score between genders. CES-D score was higher in females. Higher ASDAS-C-reactive protein (CRP) was associated with low HRQoL in both males (Odds ratio [OR] 4.25, 95% confidence interval [CI] 2.42-7.46) and females (OR 2.94, 95% CI 1.02-8.48). Being employed was associated with decreased possibility of having low HRQoL in males (OR 0.39, 95% CI 0.16-0.95). Regarding depression, higher ASDAS-CRP (OR 1.87, 95% CI 1.03-3.40), current smoking (OR 2.98, 95% CI 1.09-8.15), and being employed (OR 0.17, 95% CI 0.06-0.46) were associated with depression in males. For females, living with a partner was related to depression (OR 0.08, 95% CI 0.01-0.93). CONCLUSION: AS patients with high disease activity are likely to be suffering from low HRQoL. Both disease-related factors and contextual factors were associated with depression, and predictors showed some differences between genders. Awareness of gender differences in comprehensive assessment can lead us to better personalized management in AS patients.

Uptake of Biosimilars and Its Economic Implication for the Treatment of Patients with Rheumatoid Arthritis in Korea.

BACKGROUND: We aimed to examine the uptake of infliximab and etanercept biosimilars in patients with rheumatoid arthritis (RA) and its economic implication for healthcare expenditure. METHODS: Using Korean Health Insurance Review and Assessment Service National Patient Samples, we extracted RA patients who used biologic disease modifying anti-rheumatic drugs (bDMARDs) between 2009 and 2018. Descriptive statistics were used to explain the basic features of the data. We calculated the proportion of users of each bDMARD among total patients with bDMARDs half-yearly. We assessed changes in the utilization proportions of bDMARDs including 4 tumor necrosis factor inhibitors (TNFis) and 2 non-TNFis, which have been approved for RA in Korea: etanercept, infliximab, adalimumab, golimumab, tocilizumab, and abatacept, and analyzed the changes in market share of biosimilars among the bDMARDs after their introduction. Overall trends of medical costs for each bDMARD were presented over the 10-year period. RESULTS: Since the introduction of the biosimilar TNFis in 2012, the proportion of their use among bDMARDs steadily increased to 15.8% in 2018. While there has been a gradual increase in the use of biosimilar TNFis, the use of the corresponding originators has been decreasing. The introduction of biosimilar TNFis has resulted in a decrease in the medical costs of patients using either originator or biosimilar TNFis. CONCLUSION: In Korea, the proportional use of biosimilar TNFis has gradually increased since their introduction. The availability of less expensive biosimilar TNFis seems to have brought about a decrease in the medical costs of users of the originators.

Risk of Tuberculosis Development in Patients with Rheumatoid Arthritis Receiving Targeted Therapy: a Prospective Single Center Cohort Study.

BACKGROUND: Patients with rheumatoid arthritis (RA) undergoing targeted therapy have a higher risk of developing tuberculosis (TB). This requires diagnosis and treatment of latent tuberculosis infection (LTBI). We aimed to evaluate whether diagnosis and treatment of LTBI in RA are effective in Korea, and to estimate the risk of TB development by calculating the incidence rate of active TB among RA patients receiving targeted therapy. METHODS: We analyzed data from two prospective cohort studies of RA patients who received biologic disease-modifying antirheumatic drugs (bDMARDs) or Janus kinase (JAK) inhibitor. We selected new starters of targeted therapy and classified them into three groups receiving tumor necrosis factor (TNF) inhibitor, non-TNF inhibitor, and JAK inhibitor, respectively. We then compared LTBI prevalence, treatments, and active TB incidence during first-line therapy in each group. RESULTS: A total of 765 RA patients (574 TNF inhibitor users, 132 non-TNF inhibitor users, and 59 JAK inhibitor users) were included in this study. Observation periods were 1,255.2 person-years (PYs), 264.7 PYs, and 53.3 PYs, respectively. All 765 patients underwent LTBI screening, and the positivity rate was 26.5% (n = 203). Of the 203 LTBI-positive patients, 189 (93.1%) received treatment. Only one patient, who was in the TNF inhibitor group, and was negative for the interferon gamma release assay (IGRA), did not receive LTBI treatment and developed active TB during follow-up. CONCLUSION: Although the prevalence of LTBI in RA patients who started targeted therapy was slightly elevated, the Korean guidelines specifying LTBI screening and treatment were effective in preventing latent TB from becoming active.

Fracture Risk and Its Prevention Patterns in Korean Patients with Polymyalgia Rheumatica: a Retrospective Cohort Study.

BACKGROUND: To evaluate the incidence of fractures and fracture risk factors in Korean patients with polymyalgia rheumatica (PMR). METHODS: All PMR patients who visited a rheumatology clinic at a tertiary referral hospital between March 2005 and March 2018 were retrospectively assessed. We estimated bone mineral density (BMD) screening rate within 6 months of the first visit and classified the patients according to the performance and results of BMD screening. Incidence rates (IRs) of fractures were calculated in each group and risk factors for fractures were identified using Poisson regression analysis. RESULTS: A total of 95 PMR patients with median (interquartile range) age of 64.0 (56.0-72.0) years were included. Baseline BMD was assessed in only 55.8% of these patients (n = 53); 24 patients with osteoporosis, 20 with osteopenia, and 9 with normal BMD. During 433.1 person-years (PYs) of observation, 17 fractures occurred in 12 patients (IR, 3.93 [95% confidence interval (CI), 2.46-6.26]/100 PYs); 8.32 (95% CI, 4.09-16.90)/100 PYs in the osteopenia group, 3.40 (95% CI, 1.30-8.90)/100 PYs in the osteoporosis group, and 3.37 (95% CI, 1.53-7.39)/100 PYs in the no BMD test group. Risk factors for fractures were female sex, advanced age (≥ 65 years), longer follow-up duration, initial glucocorticoid dose ≥ 10 mg/day, and higher cumulative glucocorticoid dose over the first 6 months. CONCLUSION: The incidence rate of fractures in Korean patients with PMR was 3.93/100 PYs. Female sex, advanced age, longer follow-up duration, and increased glucocorticoid dose are risk factors for osteoporotic fracture.

Genome-wide association study in a Korean population identifies six novel susceptibility loci for rheumatoid arthritis.

OBJECTIVE: Genome-wide association studies (GWAS) in rheumatoid arthritis (RA) have discovered over 100 RA loci, explaining patient-relevant RA pathogenesis but showing a large fraction of missing heritability. As a continuous effort, we conducted GWAS in a large Korean RA case-control population. METHODS: We newly generated genome-wide variant data in two independent Korean cohorts comprising 4068 RA cases and 36 487 controls, followed by a whole-genome imputation and a meta-analysis of the disease association results in the two cohorts. By integrating publicly available omics data with the GWAS results, a series of bioinformatic analyses were conducted to prioritise the RA-risk genes in RA loci and to dissect biological mechanisms underlying disease associations. RESULTS: We identified six new RA-risk loci (SLAMF6, CXCL13, SWAP70, NFKBIA, ZFP36L1 and LINC00158) with pmeta<5×10-8 and consistent disease effect sizes in the two cohorts. A total of 122 genes were prioritised from the 6 novel and 13 replicated RA loci based on physical distance, regulatory variants and chromatin interaction. Bioinformatics analyses highlighted potentially RA-relevant tissues (including immune tissues, lung and small intestine) with tissue-specific expression of RA-associated genes and suggested the immune-related gene sets (such as CD40 pathway, IL-21-mediated pathway and citrullination) and the risk-allele sharing with other diseases. CONCLUSION: This study identified six new RA-associated loci that contributed to better understanding of the genetic aetiology and biology in RA.

WO3-ZnO and CuO-ZnO nanocomposites as highly efficient photoanodes under visible light illumination.

We prepared ZnO nanocomposites with WO3 or CuO nanostructures to improve the photocatalytic performance of ZnO nanostructures. Characterization of the nanocomposites using scanning electron microscopy, x-ray diffraction, UV-vis spectrometry and photoluminescence revealed the morphologies and wide light absorption range of the materials. The highest current densities of WO3/ZnO and CuO/ZnO nanocomposites were 1.28 mA cm-2 and 2.49 mA cm-2 at 1.23 V (versus a reversible hydrogen electrode) under AM 1.5 100 mW cm-2, which are ~1.2- and 3.5-fold greater than those of bare ZnO nanostructures, respectively. The easy fabrication process suggests that nanocomposites with narrow bandgap materials, such as WO3 and CuO, will improve the performance of electrochemical and optoelectrical devices such as dye-sensitized solar cells and biosensors.

Validation of claims-based algorithms for psoriatic arthritis.

PURPOSE: An increasing number of new medications are being developed and approved for psoriatic arthritis (PsA). To generate real-world evidence on comparative safety and effectiveness of these drugs, a claims-based algorithm that can accurately identify PsA is greatly needed. METHODS: To identify patients with PsA, we developed seven claims-based algorithms based on a combination of diagnosis codes and medication dispensing using the claims data from Medicare parts A/B/D linked to electronic medical records (2012-2014). Two physicians independently conducted a chart review using the treating physician's diagnosis of PsA as the gold standard. We calculated the positive predictive value (PPV) and 95% confidence intervals of each algorithm. RESULTS: Of the total 2157 records identified by the seven algorithms, 45% of the records had relevant clinical data to determine the presence of PsA. The PPV of the algorithms ranged from 75.2% (algorithm 1: ≥2 diagnosis codes for PsA and ≥1 diagnosis code for psoriasis) to 88.6% (algorithm 7: ≥2 diagnosis codes for PsA with ≥1 code by rheumatologist and ≥1 dispensing for PsA medication). Having ≥2 diagnosis codes and ≥1 dispensing for PsA medications (algorithm 6) also had PPV of 82.4%. CONCLUSIONS: All seven claims-based algorithms demonstrated a moderately high PPV of 75% to 89% in identifying PsA. The use of ≥2 diagnosis codes plus ≥1 prescription claim for PsA appears to be a valid and efficient tool in identifying PsA patients in the claims data, while broader algorithms based on diagnoses without a prescription claim also have reasonably good PPVs.

The Prevalence of Sjögren's Syndrome in Rheumatoid Arthritis Patients and Their Clinical Features.

BACKGROUND: To estimate the prevalence of Sjögren's syndrome (SS) in patients with rheumatoid arthritis (RA) and to compare the clinical features of RA patients with and without SS. METHODS: We conducted a retrospective study of RA patients who visited a rheumatology clinic in a tertiary referral hospital in Korea between May 20 and July 22, 2016. All patients fulfilled the classification criteria for RA, and the diagnosis of SS was made clinically by rheumatologists and according to the 2002 American-European Consensus Group (AECG), 2012 American College of Rheumatology (ACR), and 2016 ACR/European League Against Rheumatism (EULAR) classification criteria. The prevalence was estimated as the number of SS patients within the total number of RA patients. The disease activity and treatment pattern of RA were compared between patients with and without SS. RESULTS: Among 827 RA patients, 72 patients (8.7%) were diagnosed with SS by a rheumatologist, though only 60 patients (7.3%) satisfied the 2002 AECG classification criteria for SS. Fifty-two patients (6.3%) and 56 patients (6.8%) fulfilled the 2012 ACR and 2016 ACR/EULAR classification criteria, respectively. The prevalence of SS in RA patients was 10.5%, 17.0%, and 67.6% in rheumatoid factor, antinuclear antibody (≥ 1:80), and anti-Ro antibody positive patients, respectively. CONCLUSION: The prevalence of SS among RA patients was 8.7% according to rheumatologists' diagnosis. The presence of SS did not affect the treatment patterns of RA patients. However, the autoantibody profiles and demographics of RA patients with SS differed from those of patients without SS.

Increased risk of malignancy in patients aged over 50 with idiopathic inflammatory myositis compared to patients with osteoarthritis of the knee.

Objectives: To estimate risk of malignancy in patients with idiopathic inflammatory myositis (IIM) compared to patients with knee osteoarthritis (OA).Methods: Patients with IIM and knee OA aged over 50, who had no history of malignancy, were identified using Korean National claims database from January 2012 to December 2014. They had been observed until a malignancy was diagnosed or up to the end of the study, December 2015. The incidence rate (IR) of malignancy in IIM patients was calculated and compared with knee OA patients using standardized incidence ratio (SIR).Results: A total of 634 polymyositis (PM) and 556 dermatomyositis (DM) patients were included. Overall, 100 solid (IR 270.4/10,000 person-years (PY), 95% confidence interval (CI) 217.4-323.4) and 12 hematologic malignancies (IR 32.4/10,000 PY, 95% CI 14.1-50.8) occurred. Compared with knee OA, risk of overall (SIR 1.5, 95% CI 1.2-1.8), solid (SIR 1.4, 95% CI 1.1-1.6), and hematologic malignancy (SIR 5.7, 95% CI 2.5-9.0) were increased in IIM patients. This was due to increased incidence of malignancy in DM (hematologic malignancy, SIR 8.7, 95% CI 2.7-14.7, solid malignancy, SIR 1.5, 95% CI 1.1-1.9).Conclusion: Patients with IIM, especially DM, have an increased risk of malignancy compared to patients with knee OA.

Malignancy risk in Korean male patients with ankylosing spondylitis.

The objective of this study is to determine the overall and specific cancer risks in male patients with ankylosing spondylitis (AS). From the claims database of the Health Insurance and Review Assessment, male patients with AS without prior cancer history were selected (n = 21,780). Stratified random samples of claims data were used as a reference general male population group (n = 342,361). Incidence rates of overall and types of cancer were presented as number of events per 10,000 person-years with 95% confidence interval (CI). A standardized incidence ratio (SIR) was used to represent the association between AS and cancer, accounting for person-years at risk. Compared to a general male population group, the overall incidence of cancer was increased in male patients with AS (SIR 1.25, 95% CI 1.15-1.36). For specific malignancy types, the risks of male reproductive system malignancy (SIR 1.97, 95% CI 1.59-2.35) and pancreatic cancer (SIR 1.75, 95% CI 1.12-2.37) were increased. Male patients with AS had increased cancer risk, especially for male reproductive system and pancreatic cancer.

Incidence and Prevalence of Idiopathic Inflammatory Myopathies in Korea: a Nationwide Population-based Study.

BACKGROUND: This study aimed to estimate the incidence and prevalence of idiopathic inflammatory myopathies (IIM) and associated comorbidities in Korea from 2006 to 2015. METHODS: IIM between 2004 to 2015 were identified using the Korean National Health Insurance Service medical claim database. The case definition required more than one visit based on diagnostic codes including juvenile dermatomyositis (JDM), dermatomyositis (DM), or polymyositis (PM) and registration in the Individual Copayment Beneficiaries Program (ICBP) for rare and intractable diseases. IIM patients with a disease-free period of 24 months before the index date were defined as incident cases. The Elixhauser comorbidity score was calculated. RESULTS: Using the base case definition, 1,150 prevalent patients with IIM (117 JDM, 521 DM, 512 PM) were recorded in 2006 and 2,210 (130 JDM, 1,101 DM, 869 PM) in 2015. The prevalence was estimated at 2.3-4.0 (0.9-1.2 for JDM, 1.2-2.7 for DM, 1.4-2.1 for PM)/100,000 person-year (PY). We identified 218 incident cases of IIM in 2006 (18 JDM, 98 DM, 102 PM) and 191 cases (7 JDM, 83 DM, 101 PM) in 2015. The incidence was estimated at 2.9-5.2 (0.7-1.9 for JDM, 1.8-4.0 for DM, 1.6-3.0 for PM)/1,000,000 PY. The mean age (± standard deviation) of prevalent patients with IIM was 51.2 (± 16.9) years, and the percentage of women was 72.1%. More than two-thirds of patients (70.7%) had more than two comorbidities. Twenty percent of patients had interstitial lung diseases. CONCLUSION: In Korea, the incidence and prevalence of IIM were 2.9-5.2/1,000,000 PY and 2.3-4.0/100,000 PY, respectively.

Update on the prevalence and incidence of rheumatoid arthritis in Korea and an analysis of medical care and drug utilization.

The objectives of this study are to identify the prevalence and incidence of rheumatoid arthritis (RA) and to investigate the patterns of medical care and drug utilization by RA patients in Korea. Korean National Health Insurance claims data were used for analysis. RA patients were defined as those having an RA code from 2009 to 2012 and using disease-modifying anti-rheumatic drugs (DMARDs) within 1 year after the code. RA patients identified in 2010 with a disease-free period for 12 months before the index date, and those who received continuous treatment in 2011-2013 were defined as incident cases. Patterns of medical care and drug utilization were compared among subgroups. The prevalence of RA increased yearly from 0.28% in 2009 to 0.32% in 2012. The incidence of RA in 2010 was 28.5 per 100,000 person-years. The use of biologic DMARDs (bDMARDs) increased from 2.31% in 2009 to 4.05% in 2012. Hydroxychloroquine (57.53-62.45%) was the most commonly used the conventional DMARDs, followed by methotrexate (49.99-51.87%). The use of bDMARDs (1.39 vs. 2.43%) was less frequent in EORA patients than YORA patients. Hydroxychloroquine (74.96 vs. 72.11%) was more frequently used, but methotrexate (55.24 vs. 59.25%) and sulfasalazine (27.96 vs. 32.72%) were used less frequently in EORA patients than in YORA patients. The prevalence of RA has increased in Korea. EORA patients used fewer bDMARDs, methotrexate, and sulfasalazine but more hydroxychloroquine than YORA patients.

Impact of Osteoarthritis on Household Catastrophic Health Expenditures in Korea.

BACKGROUND: Osteoarthritis (OA) is a disease of old age whose prevalence is increasing. This study explored the impact of OA on household catastrophic health expenditure (CHE) in Korea. METHODS: We used data on 5,200 households from the Korea Health Panel Survey in 2013 and estimated annual living expenses and out-of-pocket (OOP) payments. Household CHE was defined when a household's total OOP health payments exceeded 10%, 20%, 30%, or 40% of the household's capacity to pay. To compare the OOP payments of households with OA individuals and those without OA, OA households were matched 1:1 with households containing a member with other chronic disease such as neoplasm, hypertension, heart disease, cerebrovascular disease, diabetes, or osteoporosis. The impact of OA on CHE was determined by multivariable logistic analysis. RESULTS: A total of 1,289 households were included, and households with and without OA patients paid mean annual OOP payments of $2,789 and $2,607, respectively. The prevalence of household CHE at thresholds of 10%, 20%, 30%, and 40% were higher in households with OA patients than in those without OA patients (P < 0.001). The presence of OA patients in each household contributed significantly to CHE at thresholds of 10% (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.16-1.87), 20% (OR, 1.29; 95% CI, 1.01-1.66), and 30% (OR, 1.37; 95% CI, 1.05-1.78), but not of 40% (OR, 1.17; 95% CI, 0.87-1.57). CONCLUSION: The presence of OA patients in Korean households is significantly related to CHE. Policy makers should try to reduce OOP payments in households with OA patients.