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 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 analysed to assess treatment-induced expression changes that differed between highly reliable excellent responders 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 IFN 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.

CONCLUSION

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.

Effectiveness of Korean Red Ginseng on fatigue in patients with rheumatic diseases: a randomized, double-blind, placebo-controlled study

Background

To evaluate the effectiveness of Korean Red Ginseng (KRG) in managing fatigue in Korean patients with rheumatic diseases.

Methods

Patients were randomly assigned to KRG (2 g/day, n = 60) or placebo (n = 60) groups for 12 weeks of blind phase and then open-label KRG from weeks 12 to 24 (placebo-KRG, continuous-KRG). The primary outcome was the improvement rate in fatigue, defined by an increase in Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue scores at 12 weeks. Secondary outcomes included changes in FACIT-Fatigue and fatigue visual analog scale (VAS) between 0 and 12 weeks and those changes in both indices at 24 weeks.

Results

The study enrolled 120 patients (Sjogren syndrome [n = 53], rheumatoid arthritis [n = 43], or both diseases [n = 24]). The mean age was 50.9 ± 11.6 years, with 97.5% being female. Baseline characteristics were similar between the two groups. The improvement rate in FACIT-Fatigue after 12 weeks was higher in the KRG group than in the placebo group, but the difference was statistically insignificant (38.3% vs. 26.7%, p = 0.242). Improvement in fatigue was observed in both groups by increases in FACIT-F (4.6 vs. 4.0) and reductions in fatigue VAS (-16.0 vs. -12.2) scores at 12 weeks. The most frequently reported adverse events during KRG use were pruritus and urticarial, with no significant difference between the two groups.

Conclusions

Both KRG and placebo groups showed significant reductions in fatigue. KRG treatment for 24 weeks did not reduce fatigue symptoms more than the placebo in patients with rheumatic diseases.

Medication utilisation trends during pregnancy and factors influencing adverse pregnancy outcomes in patients with rheumatoid arthritis

OBJECTIVES

We aimed to investigate medication utilisation trends during pregnancy and identify factors associated with adverse pregnancy outcomes (APOs) in patients with rheumatoid arthritis (RA).

METHODS

Female patients with RA aged 20-50 years were identified from the Korean national health insurance database between 2010 and 2020. Pregnancy episodes were divided into two groups according to pregnancy outcome: the delivery group and the APO group (abortion and stillbirth). The characteristics and medication utilisation patterns were compared between the two groups, and multivariable logistic regression analysis was conducted to identify the factors associated with APOs.

RESULTS

A total of 5728 pregnancy episodes were included, comprising 4576 delivery episodes and 1152 APO episodes. The mean maternal age for all pregnancy episodes was 33.7 years; 33.3 years in the delivery group and 33.7 years in the APO group. Hydroxychloroquine was the most commonly used conventional synthetic disease-modifying antirheumatic drug (DMARD) during the preconception period and pregnancy in both groups. The prescription rate of all DMARDs decreased rapidly during pregnancy. In the multivariable analysis, use of methotrexate (adjusted OR (aOR): 2.14, 95% CI 1.57 to 2.92) and leflunomide (aOR: 2.68, 95% CI 1.39 to 5.15) within 3 months before conception was associated with APOs.

CONCLUSION

Methotrexate and leflunomide are associated with an increased possibility of APOs, emphasising the importance of appropriate medication adjustment when planning for pregnancy.

Association of HLA-DRB1 locus with treatment response to abatacept or TNF inhibitors in patients with seropositive rheumatoid arthritis

The strongest genetic risk factor for rheumatoid arthritis (RA) has been known as HLA-DRB1 based on amino acid positions 11, 71, and 74. This study analyzed the association between specific HLA-DRB1 locus and treatment response to abatacept or TNF inhibitors (TNFi) in patients with seropositive RA. A total of 374 Korean RA patients were treated with abatacept (n = 110) or TNFi (n = 264). Associations between HLA-DRB1 and treatment response after 6 months were analyzed using multivariable logistic regression. Seropositive RA patients with HLA-DRB1 shared epitope (SE) had a favorable response to abatacept (OR = 3.67, P = 0.067) and an inversely associated response to TNFi (OR 0.57, P = 0.058) based on EULAR response criteria, but the difference was not statistically significant in comparison to those without SE. In analyses using amino acid positions of HLA-DRB1, a significant association was found between valine at amino acid position 11 of SE and good response to abatacept (OR = 6.46, P = 5.4 × 10-3). The VRA haplotype also showed a good response to abatacept (OR = 4.56, P = 0.013), but not to TNFi. Our results suggest that treatment response to abatacept or TNFi may differ depending on HLA-DRB1 locus in seropositive RA, providing valuable insights for selecting optimal therapy.

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.

Increased cardiovascular risk in Korean patients with systemic lupus erythematosus: a population-based cohort study

To determine the increased risk of major adverse cardiovascular events (MACE) in patients with systemic lupus erythematosus (SLE) compared to the general population in Korea. Using data from the National Health Insurance Service database spanning 2008 to 2018, incident SLE patients aged 18 years and above were selected along with a 1:4 age- and sex-matched control group. The crude incidence rate (IR) of MACE was calculated as the number of events per 1000 person-years and the IR ratio (IRR) for MACE was adjusted using generalized estimating equations. Subgroup analysis was conducted to evaluate the risk differences of overall MACE and its composites based on age and sex stratification. The study included 8568 SLE patients and 34,272 controls. The cumulative IR of MACE per 1000 person-years in SLE patients and controls were 4.08 and 1.30, respectively. After adjusting for confounders, SLE patients had a higher risk of MACE compared to the general population (adjusted IRR of 2.40 [95% confidence interval [CI] 1.88-3.05]), with no gender differences observed. The increased risk of MACE in SLE patients was highest in the 18-39 age group (IRR 11.70, 95% CI 5.95-23.01) and gradually decreased with age. The increased risk of ischemic stroke (IRR 2.41, 95% CI 1.84-3.15) and myocardial infarction (IRR 2.19, 95% CI 1.30-3.68) in SLE patients was comparable. The risk of MACE in SLE patients is 2.40 times higher than that of the general population, with a higher relative risk observed in younger individuals.

Identifying pregnancy episodes and estimating the last menstrual period using an administrative database in Korea: an application to patients with systemic lupus erythematosus

OBJECTIVES

This study developed an algorithm for identifying pregnancy episodes and estimating the last menstrual period (LMP) in an administrative claims database and applied it to investigate the use of pregnancy-incompatible immunosuppressants among pregnant women with systemic lupus erythematosus (SLE).

METHODS

An algorithm was developed and applied to a nationwide claims database in Korea. Pregnancy episodes were identified using a hierarchy of pregnancy outcomes and clinically plausible periods for subsequent episodes. The LMP was estimated using preterm delivery, sonography, and abortion procedure codes. Otherwise, outcome-specific estimates were applied, assigning a fixed gestational age to the corresponding pregnancy outcome. The algorithm was used to examine the prevalence of pregnancies and utilization of pregnancy-incompatible immunosuppressants (cyclophosphamide [CYC]/mycophenolate mofetil [MMF]/methotrexate [MTX]) and non-steroidal anti-inflammatory drugs (NSAIDs) during pregnancy in SLE patients.

RESULTS

The pregnancy outcomes identified in SLE patients included live births (67%), stillbirths (2%), and abortions (31%). The LMP was mostly estimated with outcome-specific estimates for full-term births (92.3%) and using sonography procedure codes (54.7%) and preterm delivery diagnosis codes (37.9%) for preterm births. The use of CYC/MMF/MTX decreased from 7.6% during preconception to 0.2% at the end of pregnancy. CYC/MMF/MTX use was observed in 3.6% of women within 3 months preconception and 2.5% during 0-7 weeks of pregnancy.

CONCLUSIONS

This study presents the first pregnancy algorithm using a Korean administrative claims database. Although further validation is necessary, this study provides a foundation for evaluating the safety of medications during pregnancy using secondary databases in Korea, especially for rare diseases.

Risk of end-stage renal disease in patients with early-onset lupus nephritis: A population-based cohort study

OBJECTIVE

To compare the risk of end-stage renal disease (ESRD) between patients with early-onset lupus nephritis (EOLN) and those with delayed-onset LN (DOLN).

METHODS

This retrospective study of incident cases of systemic lupus erythematosus (SLE) used nationwide Korean claims databases and data from 2008 through 2018. We divided LN patients into two groups: the EOLN group (with LN onset within 12 months of SLE diagnoses) and the DOLN group (with LN onset later than 12 months after SLE diagnoses). Patients were observed from the date of LN diagnosis to the development of ESRD, death, or the last follow-up. Cox proportional hazards modeling was used to predict hazard ratios (HRs) for progression to ESRD with death as a competing risk.

RESULTS

We identified 3779 incident SLE patients who developed LN during follow-up: 60 % (n = 2281) had EOLN, and 40 % (n = 1489) had DOLN. Sixty-nine patients with EOLN (3.0 %) and 29 patients with DOLN (1.9 %) progressed to ESRD. After adjusting for confounders, the ESRD risk associated with EOLN was comparable to the risk associated with DOLN (HR 1.10, 95 % confidence interval [CI] 0.57 to 2.11). In the subgroup of patients on aggressive immunosuppressive therapy (670 with EOLN and 179 with DOLN), the ESRD risk was higher in the DOLN group (HR 2.6, 95 % CI 1.11 to 6.10).

CONCLUSION

The risk of ESRD was comparable between patients with EOLN and DOLN. However, among patients on aggressive immunosuppressive therapy, compared with EOLN, DOLN was associated with a higher risk of progression to ESRD.

Epidemiology of systemic lupus erythematosus in Korea

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by diverse organ system disabilities, predominantly affecting young females. The clinical manifestations of SLE encompass various organs, including the kidney, cardiovascular system, and central nervous system. Young females with SLE experience higher mortality rates than the general population, making it imperative to gain insights into the disease patterns and associated factors. The current review examines the epidemiological studies to analyze the prevalence, incidence, and mortality trends of SLE in Korea and compares them with the findings from other countries. We aim to identify potential similarities, differences, and factors contributing to the burden of SLE in different populations by exploring the comparative epidemiological aspects. The knowledge derived from this comparison would aid in advancing the overall management of SLE in Korea.

Risk of venous thromboembolism in Korean patients with rheumatoid arthritis treated with Janus kinase inhibitors: A nationwide population-based study

OBJECTIVE

There was a safety concern about an increased risk of thromboembolic events in patients with rheumatoid arthritis (RA) treated with Janus kinase inhibitors (JAKis). This study aimed to determine the risk of venous thromboembolism (VTE) in Korean patients with RA treated with JAKis compared with tumour necrosis factor (TNF) inhibitors.

METHODS

Using the National Health Insurance Service database between 2015 and 2019, patients with prevalent RA who started JAKi or TNF inhibitor were selected as the study population. All participants were naïve to targeted therapy. Patients that had experienced any VTE event or used anticoagulant agents within 30 days were excluded. Demographic and clinical characteristics were all balanced by stabilised inverse probability of treatment weighting (sIPTW) using propensity score. The Cox proportional hazard model considering death as a competing risk was used to evaluate the risk of VTE in JAKi users compared with TNF inhibitor users.

RESULTS

A total of 4,178 patients were included: 871 JAKi users and 3,307 TNF inhibitor users were followed up for 1,029.2 person-years (PYs) and 5,940.3 PYs, respectively. With a balanced sample after sIPTW, the incidence rates (IR) of VTE were 0.06 per 100 PYs (95% confidence interval [CI] 0.00-1.23) in JAKi users and 0.38 per 100 PYs (95% CI 0.25-0.58) in TNF inhibitor users. The hazard ratio was 0.18 (95% CI 0.01-3.47) after adjusting for unbalanced variables after performing sIPTW.

CONCLUSION

There is no increased risk of VTE in RA patients treated with JAKis compared with TNF inhibitors in Korea.

Comparative effectiveness of JAK inhibitors and biologic disease-modifying antirheumatic drugs in patients with rheumatoid arthritis

Background/Aims

We aimed to compare the effectiveness and safety of Janus kinase inhibitors (JAKi) vs. biologic disease- modifying antirheumatic drugs (bDMARD) in Korean patients with rheumatoid arthritis (RA) who had an inadequate response to conventional synthetic DMARDs.

Methods

A quasi-experimental, multi-center, prospective, non-randomized study was conducted to compare response rates between JAKi and bDMARDs in patients with RA naïve to targeted therapy. An interim analysis was performed to estimate the proportion of patients achieving low disease activity (LDA) based on disease activity score (DAS)-28- erythroid sedimentation rate (ESR) (DAS28-ESR) at 24 weeks after treatment initiation and to evaluate the development of adverse events (AEs).

Results

Among 506 patients enrolled from 17 institutions between April 2020 and August 2022, 346 (196 JAKi group and 150 bDMARD group) were included in the analysis. After 24 weeks of treatment, 49.0% of JAKi users and 48.7% of bDMARD users achieved LDA (p = 0.954). DAS28-ESR remission rates were also comparable between JAKi and bDMARD users (30.1% and 31.3%, respectively; p = 0.806). The frequency of AEs reported in the JAKi group was numerically higher than that in the bDMARDs group, but the frequencies of serious and severe AEs were comparable between the groups.

Conclusions

Our interim findings reveal JAKi have comparable effectiveness and safety to bDMARDs at 24 weeks after treatment initiation.

Increased risk of herpes zoster with tofacitinib treatment in Korean patients with rheumatoid arthritis: a single-center prospective study

We aimed to determine the risk of herpes zoster (HZ) in Korean rheumatoid arthritis (RA) patients on tofacitinib compared with tumor necrosis factor inhibitor (TNFi) treatment. From the prospective cohorts of RA patients who started tofacitinib or TNFi in an academic referral hospital in Korea, patients who started tofacitinib between March 2017 and May 2021 and those who started TNFi between July 2011 and May 2021 were included. Baseline characteristics of tofacitinib and TNFi users were balanced through inverse probability of treatment weighting (IPTW) using the propensity score including age, disease activity of RA and medication use. The incidence rate of HZ in each group and incidence rate ratio (IRR) were calculated. A total of 912 patients were included: 200 tofacitinib and 712 TNFi users. There were 20 cases of HZ among tofacitinib users and 36 among TNFi users during observation period of 331.4 person-years (PYs) and 1950.7 PYs, respectively. In IPTW analysis with a balanced sample, IRR of HZ was 8.33 (95% confidence interval 3.05-22.76). Tofacitinib use increased the risk of HZ compared with TNFi in Korean patients with RA, but the rate of serious HZ or permanent discontinuation of tofacitinib due to HZ event was low.

Clinical characteristics of rheumatoid arthritis patients with interstitial lung disease: baseline data of a single-center prospective cohort

BACKGROUND

To introduce a prospective cohort for rheumatoid arthritis (RA) patients with interstitial lung disease (ILD) and to identify their clinical features in comparison with RA patients without ILD.

METHODS

Using a multidisciplinary collaborative approach, a single-center cohort for RA patients with ILD (RA-ILD) was established in May 2017, and enrolment data from May 2017 to March 2021 were used to compare the clinical features of RA patients without ILD (RA-non ILD). Multivariable logistic regression analysis was used to identify factors associated with ILD in RA patients.

RESULTS

Among 148 RA-ILD and 410 RA-non ILD patients, participants in the RA-ILD group were older (65.8 ± 9.9 vs. 58.0 ± 10.4 years, P < 0.001) and included more males (35.8% vs. 14.6%, P < 0.001) than in the RA-non ILD group. The RA-ILD group had a higher proportion of late-onset RA patients (age ≥ 60 years) than in the comparator group (43.9% vs. 14.2%, P < 0.001). Multivariable logistic regression analysis showed that higher age at RA onset (OR 1.056, 95% CI 1.021-1.091), higher body mass index (BMI; OR 1.65, 95% CI 1.036-2.629), smoking history (OR 2.484, 95% CI 1.071-5.764), and oral glucocorticoid use (OR 3.562, 95% CI 2.160-5.874) were associated with ILD in RA patients, whereas methotrexate use was less likely to be associated with ILD (OR 0.253, 95% CI 0.155-0.412).

CONCLUSIONS

Higher age at RA onset, smoking history, and higher BMI were associated with the presence of ILD among RA patients. Oral glucocorticoids were more frequently used whereas methotrexate was less likely to be used in RA-ILD patients.

Factors associated with selection of targeted therapy in patients with rheumatoid arthritis

OBJECTIVE

Deciding which drug to choose for targeted therapy is an important step in sequential treatment for rheumatoid arthritis (RA). This study aimed to identify factors for selecting Janus kinase inhibitors (JAKis) rather than biologic disease-modifying antirheumatic drugs (bDMARDs) in patients with RA in real-world practice.

METHODS

We selected RA patients starting JAKis or bDMARDs from single-center prospective cohorts in Korea. Patients were divided into JAKi, tumor necrosis factor (TNF) inhibitor, and non-TNF inhibitor groups. We performed multinomial logistic regression analyses to identify factors associated with selecting JAKis.

RESULTS

145, 205, and 89 patients were included in the JAKi, TNF inhibitor, and non-TNF inhibitor groups. In multinomial regression analysis, the JAKi group was older than the TNF inhibitor group (OR 1.03, 95% confidence interval [CI] 1.01-1.05) but younger than the non-TNF inhibitor group (OR 0.97, CI 0.95-1.00). The JAKi group was less likely to have chronic pulmonary diseases compared with the TNF inhibitor group (OR 0.07, CI 0.01-0.56) or the non-TNF inhibitor group (OR 0.06, CI 0.01-0.50). Higher disease activity assessed by physician (OR 1.80, CI 1.51-2.38) and previous tacrolimus use (OR 2.05, CI 1.20-3.51) were factors suggesting selection of JAKis than TNF inhibitors.

CONCLUSION

Age, pulmonary comorbidities, previous tacrolimus use, and high disease activity assessed by physician were factors influencing the selection of JAKis for RA patients in Korea.

MUC5B promoter variant rs35705950, rare but significant susceptibility locus in rheumatoid arthritis-interstitial lung disease with usual interstitial pneumonia in Asian populations

BACKGROUND

MUC5B variant rs35705950 is the common and most significant risk variant for rheumatoid arthritis-interstitial lung disease (RA-ILD) in Western populations. However, little is known about its significant association with RA-ILD in Asian populations. We here investigate the association of rs35705950 with Korean patients with RA-ILD.

METHODS

In this cross-sectional study, we genotyped rs35705950 in 2444 patients with RA. Among them, 683 patients with RA who have chest CT were divided into RA-ILD and RA-noILD. RA-ILD was classified as usual interstitial pneumonia (UIP) and other than UIP. The associations of rs35705950 with RA-ILD and its subtype were analysed using multivariable regression adjusted for age at RA diagnosis. Meta-analysis of a previously reported Japanese dataset and Korean dataset obtained for this study was conducted.

RESULTS

The minor allele (T) frequency of rs35705950 was 0.37%, 1.43% and 2.38% in 2444 patients with RA, 105 patients with RA-ILD and 63 patients with UIP, respectively. Genotypic association of rs35705950 with RA-ILD was insignificant (OR 2.49, 95% CI 0.64 to 9.69, p=0.187), but showed significant association with UIP (OR 4.90, 95% CI 1.23 to 19.59, p=0.024) compared with RA-noILD. In meta-analysis (123 UIP and 878 RA-noILD) combining our data with previously reported Japanese data, this variant was found to be significantly associated with UIP (OR 3.51, 95% CI 1.19 to 10.37, p=0.023).

CONCLUSION

MUC5B variant rs35705950 is a rare but significant risk factor for Asian patients with RA-ILD with UIP, suggesting a sharing of the genetic background between Asian and Western populations.

Association between malignancy risk and Janus kinase inhibitors versus tumour necrosis factor inhibitors in Korean patients with rheumatoid arthritis: a nationwide population-based study

OBJECTIVE

To determine the risk of malignancy in Korean patients with rheumatoid arthritis (RA) receiving Janus kinase inhibitors (JAKis) compared with tumour necrosis factor inhibitors (TNFis).

METHODS

A retrospective cohort of patients with RA initiating their first JAKi or TNFi was established using the Korean National Health Insurance database between 2015 and 2019. They were followed up from treatment initiation to the occurrence of malignancy, drug discontinuation, death or until December 2019. Baseline features of the patients were balanced through inverse probability of treatment weighting (IPTW) using a propensity score. A Cox proportional hazard model was established to estimate the HR for malignancy risk in JAKi users compared with TNFi users.

RESULTS

A total of 4929 patients (1064 JAKi-treated and 3865 TNFi-treated patients) were included, and the observation periods were 1288.6 person-years (PYs) for JAKi users and 6823.8 PYs for TNFi users. The incidence rates of overall malignancy were 0.54 per 100 PYs (95% CI 0.26 to 1.14) in JAKi users and 0.85 per 100 PYs (95% CI 0.66 to 1.10) in TNFi users. In IPTW analysis with a balanced sample (4101 JAKi-treated and 5131 TNFi-treated patients), HR was 0.83 (95% CI 0.55 to 1.27) for overall malignancy: 0.77 (95% CI 0.50 to 1.19) for solid malignancy and 2.86 (95% CI 0.41 to 20.00) for haematological malignancy.

CONCLUSION

Malignancy risk in Korean patients with RA was not increased with JAKi use compared with TNFi use.

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.

Validation of the Korean Leeds satisfaction questionnaire in rheumatoid arthritis with Rasch models

OBJECTIVES

We conducted the cross-cultural adaptation and validation of the Leeds Satisfaction Questionnaire (LSQ) for patients with rheumatoid arthritis (RA) in Korea.

METHODS

The adaptation of the LSQ from English into Korean was based on guidelines for cross-cultural adaptation for self-report measures. Patients with RA were recruited from an outpatient clinic of a university hospital in South Korea. Validation of the Korean-LSQ with Rasch models was carried out using WINSTEPS. Model fit was determined by Infit and Outfit statistics (≥0.50 and ≤1.50), including the separation index (≥2.00) and reliability index (≥0.80).

RESULTS

The data set comprised 125 patients (82.4% female), with median (interquartile range) age 49.0 (37-57) years, and disease duration of 2.5 (1.2-3.8) years. The total and subscale scores of the Korean-LSQ demonstrated excellent or good test-retest reliability (0.88 for total, 0.71-0.82 for subscales), and items in the scale also revealed a high internal consistency (α = 0.93). The six subscales of the Korean-LSQ were found to have a good fit to the Rasch model and good reliability (Person separation index = 2.63 and reliability index = 0.87; item separation index = 37.03 and reliability index >0.99). In addition, the unidimensionality of the scale was confirmed by the principal component analysis based on the Rasch residuals.

CONCLUSION

Fit to the Rasch model confirmed that the construct validity, reliability, and unidimensionality of the LSQ were preserved following the adaptation into Korean. The Korean-LSQ is a valid and reliable tool for measuring satisfaction with care in Korean patients with RA.

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.

Risk factors for herpes zoster in Korean patients with rheumatoid arthritis treated with JAK inhibitor: a nested case-control study

OBJECTIVE

To determine the risk of herpes zoster (HZ) in Korean patients with rheumatoid arthritis (RA) receiving Janus kinase inhibitors (JAKis).

METHODS

We performed a nested case-control study with 1:10 matching for sex and age using single-centre prospective cohorts of patients with RA receiving targeted therapy in Korea. Then we performed conditional logistic regression analyses to determine the risk associated with JAKi use compared with biologic disease-modifying antirheumatic drug (bDMARD) use, with adjusting for various factors. We also used logistic regression analysis to identify other risk factors for the development of HZ in JAKi users.

RESULTS

From a total of 1147 patients, 61 cases and 610 matched controls were selected. In conditional logistic regression analysis, JAKi use did not increase the risk of HZ development (OR 1.35, 95% CI 0.70 to 2.61) after adjusting for other factors. Rather, duration of RA less than 10 years (OR 0.54, 95% CI 0.30 to 0.97) and having had three or more previous targeted therapies (OR 5.29, 95% CI 1.45 to 19.31) were risk factors for HZ. Among JAKi users, higher disease activity score 28-erythrocyte sedimentation rate (DAS28-ESR) (OR 1.44, 95% CI 1.06 to 1.97) was identified as a risk factor in addition to three or more previous targeted therapies (OR 10.12, 95% CI 1.92 to 53.49).

CONCLUSIONS

The number of previous targeted therapies, but not JAKi use, was identified as a risk factor for HZ development in Korean patients with RA in a real-world setting. High disease activity was an additional risk factor for JAKi users.

Comparative Effectiveness of Azathioprine Versus Cyclosporine as an Initial Treatment for Idiopathic Inflammatory Myopathies: A Population-Based Observational Study

Objective

To compare the effectiveness of azathioprine (AZA) and cyclosporine (CsA) as initial treatments for patients with idiopathic inflammatory myopathies (IIM).

Methods

A retrospective cohort study was conducted using information from the National Health Insurance Service database of Republic of Korea. Patients with IIM who had started AZA or CsA as initial treatment between January 2007 and December 2011 were selected for the study. They were followed from the day of treatment initiation to the occurrence of study outcomes or the end of the study until December 2016. Effectiveness outcomes, defined as switching the drug or adding immunosuppressants, and discontinuation of corticosteroids, were compared between the two groups. The Cox proportional-hazards model was used to calculate the adjusted relative risk (aRR) with 95% confidence interval (CI) between the AZA and CsA groups.

Results

A total of 376 patients with incident IIM who used AZA (n = 288) or CsA (n = 88) were identified. The aRR of switching the drug or adding immunosuppressants (1.45 [95% CI 0.99–2.11]) was not significantly different between the CsA and AZA groups. Among patients who were treated with corticosteroids at baseline, the rate of discontinuation of corticosteroids was not different between the two groups (1.69 [95% CI 0.82–3.47]).

Conclusions

The effectiveness of AZA and CsA as initial treatments for the management of IIM was comparable.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-021-00392-y.

Increased risk of malignancy in patients with systemic lupus erythematosus: population-based cohort study in Korea

Background

This study aimed to evaluate the crude incidence rates and relative risk of malignancy in Korean patients with SLE.

Methods

We conducted a retrospective nationwide cohort study using databases from the National Health Insurance Service in Korea. All prevalent SLE patients aged over 19 were identified from January 2012 to December 2014 and observed until the diagnosis of malignancy, death, or end of the study, December 2015. The crude incidence rates (IRs) and standardised incidence ratios (SIRs) of overall and site-specific malignancies in SLE patients were estimated.

Results

We identified 17,854 SLE patients and during the observation period (60,511 person-years [PYs]), 768 solid malignancies (126.9/10,000 PYs) and 68 haematologic malignancies (11.2/10,000 PYs) occurred in SLE patients. In SLE patients, breast and reproductive system and thyroid cancers occurred predominantly, followed by liver and colon cancers. The SIRs of overall, solid, and haematologic malignancies of SLE patients compared to the general population were 1.8 (95% confidence interval [CI] 1.6–1.9), 1.7 (95% CI 1.5–1.8), and 5.9 (95% CI 4.8–7.3), respectively. In solid malignancies, head and neck (2.7, 95% CI 1.1–4.2), bladder (2.4, 95% CI 1.1–3.8), liver (1.9, 95% CI 1.4–2.3), pancreas (1.9, 95% CI 1.3–2.6), lung (1.8, 95% CI 1.2–2.4), colon (1.7, 95% CI 1.3–2.2), thyroid (1.6, 95% CI 1.3–1.8) and breast and reproductive system (1.5, 95% CI 1.2–1.7) cancers are at increased risk in SLE patients.

Conclusion

An increased risk of haematologic and solid malignancies was observed in Korean patients with SLE compared to the general population.

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.

The usefulness of trabecular bone score in patients with ankylosing spondylitis

BACKGROUNDS/AIMS

This study was performed to reveal the usefulness of the trabecular bone score (TBS) in assessing bone strength in patients with ankylosing spondylitis (AS) in comparison with dual-energy X-ray absorptiometry (DXA) methods.

METHODS

A total of 215 AS patients (75.8% male) were enrolled from a single university hospital in Korea. Demographic and clinical information were assessed. Patients completed X-rays of the cervical and lumbar spine (L-spine), and spinal ankyloses were quantified using the modified Stoke AS Spine Score (mSASSS). Hip, anteroposterior and lateral L-spine bone mineral density (BMD) and TBS were assessed by DXA methods. Clinical characteristics and bone strength measurement results were compared between male and female AS patients. The accuracy of each bone strength evaluation method in predicting Fracture Risk Assessment Tool (FRAX) scores indicating moderate or higher fracture risk was compared by receiver operating characteristic curves in patients aged ≥ 40 years. Correlations between each bone strength measurement method and mSASSS were examined.

RESULTS

Male patients showed higher mSASSS and less prevalent peripheral joint involvement compared to female patients (p < 0.05). TBS, hip BMD, and L-spine lateral BMD showed comparably high areas under the curve (AUCs) for predicting FRAX-major osteoporotic fractures (MOF) ≥ 10% (AUC ranged 0.72 to 0.76). TBS negatively correlated with mSASSS in both male and female patients (p < 0.01).

CONCLUSION

TBS could predict the risk of MOF and is not influenced by spinal osteoproliferation in AS patients, even in those with advanced spinal changes.

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.

Effectiveness of bazedoxifene in preventing glucocorticoid-induced bone loss in rheumatoid arthritis patients

Objective

To evaluate the effectiveness of bazedoxifene in preventing bone loss in patients with rheumatoid arthritis (RA) receiving low-dose glucocorticoids (GCs).

Methods

In this randomized, controlled, open-label study, we assigned postmenopausal women with osteopenia who had been receiving low-dose GCs for RA to two groups: a group receiving bazedoxifene (20 mg/day) with elemental calcium 1200 mg and vitamin D 800 IU daily (bazedoxifene group) and a group receiving the same doses of calcium and vitamin D only (control group). As primary outcome, bone mineral density (BMD) change in the lumbar spine (L-spine) from baseline to 48 weeks was assessed. Changes in BMD in the femur, trabecular bone score, bone turnover markers, and development of fracture were assessed as secondary outcomes. For intention-to-treat analysis, 20 completed data sets were created by applying multiple imputations by chained equations.

Results

A total of 114 patients (57 patients in each group) were recruited. A significant increase in L-spine BMD (0.015 g/cm², P = 0.007) was observed in the bazedoxifene group, and the increase was significantly higher than in the control group (0.013, 95% CI 0.0003–0.026, P = 0.047). Reductions in bone turnover markers in the bazedoxifene group were significantly greater than in the control group. Only one fracture was observed in the bazedoxifene group, while four fractures developed in the control group.

Conclusion

In postmenopausal patients with RA receiving low-dose GCs, bazedoxifene improved BMD and reduced bone turnover markers. However, the change in BMD did not exceed the least significant change.

Trial registration

ClinicalTrials.gov, NCT02602704.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02564-1.

Developing the Korean Educational Needs Assessment Tool (Korean ENAT) in rheumatoid arthritis: cross-cultural validation using Rasch analysis

BACKGROUND/AIMS

This study was performed to undertake cross-cultural adaptation and validation of the Educational Needs Assessment Tool (ENAT) in rheumatoid arthritis (RA) for use in Korea.

METHODS

The study involved two main phases: cross-cultural adaptation of the ENAT from English into Korean, and validation of the Korean ENAT. The first phase followed the established process of cross-cultural adaptation of self-report measures, and in the second phase, the Korean ENAT data were analyzed using the Rasch measurement model. Fit to the model was determined using the observed data infit and outfit statistics. Additional tests of validity included unidimensionality and internal consistency.

RESULTS

Adequate conceptual equivalence was achieved following the adaptation process. A total of 123 patients completed the Korean ENAT. The mean age was 46.7 ± 12.3 years and the majority of patients (81.3%) were female. Thirty-five of the 39 items gave good fit to the model. The four items deviating from the model had infit and outfit > 1.50. The item separation index (5.26) and item reliability index (0.97) provided evidence for good reliability of items. All seven domains of the Korean ENAT fit the Rasch model. The internal consistency of the Korean ENAT was high, and unidimensionality was confirmed (person separation index, 3.41; reliability index, 0.92; item separation index, 16.82; reliability index, 1.00).

CONCLUSION

Using the standard procedure for cross-cultural adaptation, the ENAT has been adapted into Korean, and Rasch analysis has confirmed the construct validity, reliability, and unidimensionality of the Korean ENAT.

Comparison of healthcare resource utilization and medical costs between patients with seropositive and seronegative rheumatoid arthritis

Objectives:

To compare healthcare utilization and medical costs between patients with seronegative (SN) and seropositive (SP) rheumatoid arthritis (RA).

Methods:

We conducted a nationwide population study using the Korean health insurance claims database in 2016. We divided patients with RA into SN and SP groups and compared healthcare utilization including medications, medical utilization, and direct medical costs for 1 year between the groups in a cross-sectional analysis. Differences in costs between patients with SPRA and SNRA were assessed using the quantile regression model. We performed longitudinal analysis using data from 2012 and 2016 to examine changes over time.

Results:

A total of 103,815 SPRA and 75,809 SNRA patients were included in the analyses. The SPRA group used significantly more methotrexate (73.2% versus 30.3%) and biologic agents (7.9% versus 2.9%) than the SNRA group. The number of RA-related outpatient visits [6.0 ± 3.7 versus 4.4 ± 4.0 times/year, standardized difference (SD) = 0.41] and annual medical costs per patient ($1027 versus $450/year, SD = 0.25) were higher in the SPRA group than the SNRA group. Quantile regression results indicated that the incremental cost of seropositivity on total medical costs of RA patients gradually increased as medical costs approached the upper quantile. The annual direct medical costs for each patient between 2012 and 2016 increased in both groups: by 25.1% in the SPRA group and 37.6% in the SNRA group.

Conclusion:

Annual RA-related direct medical costs and RA-related healthcare utilization per patient are higher in patients with SPRA than those with SNRA.

Update on Glucocorticoid Induced Osteoporosis

Glucocorticoids are used to treat many autoimmune and inflammatory diseases. However, an adverse systemic effect is a deleterious effect on bone, which may lead to glucocorticoid-induced osteoporosis, characterized by a rapid and transient increase in bone resorption and fracture risk, which may increase rapidly within 3 months of commencing oral glucocorticoids. Therefore, early risk assessment and intervention are crucial for preventing fractures in patients receiving glucocorticoids. Recent practice guidelines recommend an assessment for fracture risk in patients beginning or receiving glucocorticoids for more than 3 months, and they have suggested fracture risk assessment tool values for identifying patients who need preventive treatment. Bisphosphonates are currently the recommended first-line therapy for the prevention and treatment of glucocorticoid-induced osteoporosis. These have been shown to increase the bone mineral density in the spine and hip and to decrease the incidence of vertebral fractures. Recently, a more potent antiresorptive agent, denosumab, has been shown to increase the bone density in patients receiving glucocorticoids. Teriparatide has been shown to have a preventive effect on vertebral fractures, but not on nonvertebral fractures. In this article we aimed to provide an update on glucocorticoid-induced osteoporosis by focusing on the assessment of its risk and treatment options.

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.

Intervention Thresholds for Treatment in Patients with Glucocorticoid-Induced Osteoporosis: Systematic Review of Guidelines

Background

In this study, we aimed to evaluate and compare the treatment indication for patients with glucocorticoid-induced osteoporosis (GIOP) in various clinical practice guidelines.

Methods

We searched for potentially relevant studies conducted from January 2000 to March 2020 using online databases, including PubMed, Ovid-EMBASE, Guidelines International Network, National Institute for Health and Clinical Excellence, KoreaMed, KMbase, and KoMGI. We reviewed and analyzed the guidelines that included recommendations on GIOP and fulfilled the inclusion criteria.

Results

A total of 94 articles were selected based on review of the title and abstract; 14 guidelines were assessed upon reviewing the full text. The bone mineral density score for therapeutic intervention of GIOP in postmenopausal women was presented in 7 guidelines, among which 3 guidelines set a T-score of −2.5 or lower and the other 4 guidelines proposed a less stringent cut-off point of −1.5 or lower. Among the 10 guidelines published since 2012 after the emergence of the fracture risk assessment tool (FRAX), 6 guidelines included FRAX in their criteria for defining intervention thresholds. However, they were further divided into fixed-probability (n=3) and age-dependent (n=3) thresholds based on the country.

Conclusions

Recently developed guidelines use FRAX as the criterion for establishing the treatment of patients with GIOP. However, these intervention thresholds need to be adapted for each country.

Effect of a Nationwide Real-Time Drug Utilization Review System on Duplicated Nonsteroidal Antiinflammatory Drug Prescriptions in Korea

OBJECTIVE

Since January 2013, a nationwide drug utilization review (DUR) system for therapeutic duplication (TD) of nonsteroidal antiinflammatory drugs (NSAIDs) has been implemented in Korea. Our objective was to perform an interrupted time series study to assess changes in the pattern of NSAIDs use in knee osteoarthritis patients after implementation of the regulations.

METHODS

We compared the prescribing patterns in 2012 and 2013 by means of an interrupted time series study, using the Health Insurance Review and Assessment Service database. TD was defined as use of concurrent NSAIDs either on the same or on different prescriptions for >3 days in a patient. Level change and trend change (with 95% confidence intervals [95% CIs]), and absolute and relative changes in the proportion of TDs, were estimated using segmented regression models. Multivariable logistic regression models were used to explore patient and provider characteristics associated with the TDs.

RESULTS

Approximately 2.5 million patients were prescribed NSAIDs in both 2012 and 2013. The proportion of TDs before and after introduction of the DUR system was 7.4% and 5.6%, respectively. Overall, an absolute reduction of 89% and a relative reduction of 30% in TDs were observed. In the postregulation period, older patients, medical aid subscribers (odds ratio [OR] 1.87 [95% CI 1.84, 1.90]), and veterans (OR 3.28 [95% CI 3.10, 3.46]) were most likely to receive NSAID TDs.

CONCLUSION

The prescription of NSAID TDs decreased with the introduction of the nationwide DUR system. Continuous adherence to the DUR regulations and safety monitoring are needed, especially with the elderly, medical aid subscribers, and veterans.

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.

Risk of malignancy in Korean patients with primary Sjögren's syndrome

OBJECTIVES

To evaluate the risks of overall and site-specific malignancies in Korean patients with primary Sjögren's syndrome (pSS).

METHODS

Using the Korean nationwide healthcare claims database, we constructed a retrospective cohort for prevalent pSS aged over 50 years. After enrollment between January 2012 and December 2014, patients were followed until the development of any malignancy, or until December 2015. Crude incidence rates of malignancies of pSS patients were calculated, and their standardized incidence ratios (SIRs) for malignancies were calculated compared to those in knee osteoarthritis (OA) patients.

RESULTS

A total of 6,359 pSS and 5,476,302 knee OA patients were included in this study. During follow-up (19,474 person-years [PYs]), 310 cases of solid malignancy (158.8/10,000 PYs) and 47 cases of hematologic malignancies (23.5/10,000 PYs) were observed in pSS patients. The risks of overall (SIR 1.30, 95% CI 1.16-1.43), solid (SIR 1.16, 95% CI 1.03-1.29), and hematologic malignancies (SIR 4.80, 95% CI 3.43-6.17) were increased in pSS patients. There was an elevated risk of site-specific malignancy in non-Hodgkin's lymphoma (NHL, SIR 6.45, 95% CI 4.05-8.83), multiple myeloma (SIR 4.88, 95% CI 2.00-7.76), and oropharynx (SIR 4.16, 95% CI 1.90-6.42). The risk of lung cancer was increased only in male pSS patients (2.50, 95% CI 1.02-3.99), while the risk of thyroid cancer was increased in female patients (1.44, 95% CI 1.04, 1.84).

CONCLUSION

In patients with pSS over age 50, the risk of solid cancers such as oropharynx, thyroid, and lung cancers is also increased in addition to NHL.

Treatment strategy for patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting the joints, causing joint destruction, functional disability, and reduced quality of life in patients. The aim of RA treatment is to decrease the inflammation, prevent joint damage, and improve patientsʼ quality of life while minimizing progression of the disease. Both early detection and intervention with disease-modifying anti-rheumatic drugs (DMARDs) have been reported to improve therapeutic outcomes. Treatment with DMARDs should be started immediately after the diagnosis is established, with methotrexate as the best initial drug of choice. Disease activity should be regularly monitored. Targeted therapies can be considered in patients with persistent active disease despite methotrexate therapy. Remission or low disease activity is the preferred treatment target. There are two major classes of DMARDs: conventional synthetic DMARDs and the targeted therapies specific to pro-inflammatory cytokines including biologic DMARDs and small molecule inhibitors. Recently, the importance of shared decision making, in which patients and clinicians make decisions together, and education of the patient has been emphasized in the treatment strategies of RA. This review summarizes the effectiveness and safety of the DMARDs currently available for RA treatment. Recommendations for RA management would also be discussed in this article.

Validation of claims-based algorithms to identify interstitial lung disease in patients with rheumatoid arthritis

OBJECTIVE

To develop and validate claims-based algorithms to identify interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA) METHODS: Using Medicare claims data linked with the electronic medical records (2012-2014), we first selected RA patients based on ≥2 diagnostic codes for RA and ≥1 disease-modifying antirheumatic drugs.Then, to identify ILD in RA, we developed eight claims-based algorithms using a combination of ICD-9 diagnosis codes and procedure codes related to the diagnosis or management of ILD. We assessed the positive predictive value (PPV) for each of the eight algorithms relative to confirmed ILD cases using chest computerized tomography or lung biopsy as the gold standard.

RESULTS

A total of 5,214 RA patients were included in the study, and the ILD cases identified by each algorithm ranged from 181 to 993. The PPV of the diagnosis code-based algorithms ranged from 43.4% (≥1 diagnosis code by any physician) to 52.0% (≥2 diagnosis codes by any physician). When the algorithms further required ≥1 procedure code (e.g., imaging, bronchoscopy), the PPV did not improve. However, the algorithms that required ILD diagnosis codes by specialists (i.e., pulmonologist or rheumatologist) had PPVs of 61.5% with ≥1 code; 72.4% with ≥2 codes.

CONCLUSIONS

In a cohort of RA patients, our algorithm that required ≥2 ILD diagnosis codes by specialists demonstrated a PPV of 72.4% in ascertaining ILD. Our results support the utility of the claims-based algorithm to identify a population-based cohort of RA patients with ILD using large administrative claims data.

Factors for starting biosimilar TNF inhibitors in patients with rheumatic diseases in the real world

Background

To identify factors for starting biosimilar TNF inhibitors (TNFI) in patients with rheumatic diseases.

Methods and finding

Using a national claims database, we identified patients with rheumatoid arthritis (RA) or ankylosing spondylitis (AS) who had used TNFIs since they were approved in Korea in 2004. We assessed changes in the proportion of each form of TNFI used between 2004 and 2017. We then selected patients starting on TNFIs between 2013 and 2017 to identify factors for starting biosimilars. In RA (n = 4,216), biosimilars were more likely to be initiated in clinics [odds ratio (OR) 2.54] and in the metropolitan area (OR, 2.02), but were less likely to be initiated in general hospitals (OR 0.40) or orthopedics (OR 0.44). In AS (n = 2,338), biosimilars were common at the hospital level (OR 2.20) and tended to increase over the years (OR 1.16), but were initiated less in orthopedics (OR 0.07). In addition, RA patients were more likely to initiate biosimilars in combination with methotrexate (OR 1.37), but biosimilars were not initiated frequently by patients with higher comorbidity scores (OR 0.97) or receiving glucocorticoids (OR 0.67). The patient factors favoring biosimilar in AS use were not clear.

Conclusions

In Korea, the proportion of biosimilar TNFIs has increased. Type of institution and physician specialty are more important than patient factors in affecting biosimilar use. In RA, biosimilar TNFIs tend to be initiated in combination with MTX, and are less likely to be initiated in patients taking glucocorticoids or in those with high comorbidities.

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.

International descriptive study for comparison of treatment patterns in patients with knee osteoarthritis between Korea and Japan using claims data

AIM

To compare medication prescriptions for patients with knee osteoarthritis (KOA) in the real world in Korea and Japan.

METHODS

This retrospective and descriptive population-based study was conducted using claims data provided by Health Insurance Review and Assessment in Korea and JMDC Inc in Japan. We defined individuals as KOA patients if they had an International Classification of Diseases 10 (ICD10) code for gonarthrosis (M17) and were ≥50 years old in 2012. Korean and Japanese patients were matched for age and sex using frequency matching. Patients were observed for 1 year from the first month of the ICD10 code M17 in 2012. We described baseline characteristics including prevalence of comorbidities, and use of medication for KOA during the observational period.

RESULTS

The median age was 59 and the percentage of women was 61.4 in both countries (N = 1 133 138 in Korea, N = 10 498 in Japan). The prevalence of nonsteroidal anti-inflammatory drug (NSAID) usage in Japan (74.7%) was significantly higher than that in Korea (59.0%). Analgesics such as acetaminophen and symptomatic slow-acting drugs for OA (SYSADOA) were significantly more frequently used in Korea (25.8%) than in Japan (9.4%). Intra-articular injection (IAI) of corticosteroids or hyaluronic acid was performed more frequently in Japanese patients (57.3%) than Korean patients (30.5%).

CONCLUSIONS

Medication patterns for KOA in Korea and Japan are described for the first time. Use of NSAIDs and IAI were more common in Japan, while other pain killers and SYSADOA were more commonly prescribed in Korea.

Factors related to the use of opioids as early treatment in patients with knee osteoarthritis

Objective

To examine factors related to the use of opioids as an early treatment option for knee OA patients

Methods

Using the Korean nationwide claim database, we selected knee OA patients between 2013 and 2015. Among them, patients without any claim of knee OA for 2 years before the index date were included as our study population. We analyzed their first claim for prescriptions, including tramadol and stronger opioids, at the index date of each patient. Using a multinomial model, we identified factors associated with the early use of tramadol and stronger opioids in knee OA patients.

Results

Among a total of 2,857,999 knee OA patients, 12.2% (n = 348,516) were treated with opioids as their first treatment. However, the prevalence of stronger opioid use was only 0.07% (n = 1972). Male sex (OR 1.28 in tramadol, OR 1.13 in stronger opioids) and comorbidities with depression (OR 1.05, 1.46), low back pain (OR 1.13, 1.30), intervertebral disc disorder (OR 1.11, 1.40), and spinal stenosis (OR 1.27, 1.55) were the factors for the early use of tramadol or stronger opioids in knee OA patients. Patients in a tertiary referral hospital tended to use tramadol or stronger opioids than those in clinics (OR 1.04, 56.63, respectively).

Conclusion

In Korea, 12.2% of knee OA patients were treated with opioids as an early treatment, and tramadol was used more commonly than stronger opioids. Male sex and having comorbidities such as depression or musculoskeletal disease are patient factors associated with the early use of opioids in knee OA patients.

Treatment patterns of knee osteoarthritis patients in Korea

BACKGROUND/AIMS

To evaluate the treatment patterns of knee osteoarthritis (OA) patients in South Korea.

METHODS

Using the Korean nationwide claims database, all knee OA patients in Korea during 2014 were identified by the knee OA diagnostic code (M17) or any OA diagnostic code (M15 to M19) in combination with a procedure for a knee X-ray. Patterns of medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids (CSs), analgesics, and symptomatic slow acting drugs for OA (SYSADOA) were analyzed. Prevalence and characteristics of knee OA patients who received a CS intra-articular injection (IAI) were also evaluated.

RESULTS

We identified 2,016,516 knee OA patients whose age (mean ± standard deviation) was 63.2 ± 10.8 years. The number of patients with at least one use of NSAIDs, analgesics, CS, and SYSADOA were 82.5%, 32.2%, 8.6%, and 43.4%, respectively. The use of herbal SYSADOAs was 29.7%. For regular users (medication possession ratios ≥ 50%), the use of NSAIDs was substantially decreased (48.8%), while the use of SYSADOA (37.3%) and CS (6.7%) were not significantly changed. The number of CS IAI users among knee OA patients was 0.18%; they were slightly older (64.4 ± 10.9 vs. 63.2 ± 10.8, p < 0.01) and more skewed towards females (75.7% vs. 71.5%, p < 0.01) than patients who had not received CS IAI.

CONCLUSION

In Korea, the use of SYSADOA or CS in knee OA patients was relatively high. Further studies on the effectiveness and the safety of these treatment options for knee OA are needed.

A paradigm shift in studies based on rheumatoid arthritis clinical registries

Clinical research is the study of aspects of patient health or illness that are closely related to clinical practice. In the late 20th and early 21th century, outcomes for patients with rheumatoid arthritis (RA) improved dramatically due to breakthroughs in new drugs. Patient-reported outcome measures now play a significant role in the drug development process as study endpoints in clinical trials of new therapies, and this has led to increased interest in the patient's perspective, drug safety and treatment outcomes in clinical practice. In accordance with these needs, many prospective cohorts for RA patients and registries of biologic disease modifying anti-rheumatic drugs have been actively conducted in the United States and European and Asian countries. A gradual shift is taking place in the major outcomes of clinical research using these prospective cohorts and registries. This article will introduce representative registries for RA in each country set up in the early 2000s and will discuss future perspectives in clinical research on RA patients using such clinical registries.

Deletion at 2q14.3 is associated with worse response to TNF-α blockers in patients with rheumatoid arthritis

Background

Structural variations such as copy number variations (CNVs) have a functional impact on various human traits. This study profiled genome-wide CNVs in Korean patients with rheumatoid arthritis (RA) to investigate the efficacy of treatment with TNF-α blockers.

Methods

A total of 357 Korean patients with RA were examined for the efficacy of TNF-α blocker treatment. Disease activity indexes were measured at baseline and 6 months after the treatment. The patients were classified as responders and non-responders based on the change in disease activity indexes according to the EULAR response criteria. CNVs in the same patients were profiled using fluorescence signal intensity data generated by a genome-wide SNP array. The association of CNVs with response to TNF-α blockers was analyzed by multivariate logistic regression accounting for genetic background and clinical factors including body mass index, gender, baseline disease activity, TNF-α blocker used, and methotrexate treatment.

Results

The study subjects varied in their responses to TNF-α blockers and had 286 common CNVs in autosomes. We identified that the 3.8-kb deletion at 2q14.3 in 5% of the subjects was associated with response to TNF-α blockers (1.37 × 10^− 5 ≤ P ≤ 4.07 × 10^− 4) at a false discovery rate threshold of 5%. The deletion in the identified CNV was significantly more frequent in the non-responders than in the responders, indicating worse response to TNF-α blockers in the deletion carriers. The 3.8-kb deletion at 2q14.3 is located in an intergenic region with the binding sites of two transcription factors, MAFF and MAFK.

Conclusions

This study obtained the CNV landscape of Korean patients with RA and identified the common regional deletion associated with poor response to treatment with TNF-α blockers.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1983-y) contains supplementary material, which is available to authorized users.

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.

Prevalence and predictors for sustained remission in rheumatoid arthritis

OBJECTIVE

Remission is a key goal in managing rheumatoid arthritis (RA), with sustained remission as the preferred sequelae of short-term remission. However little is known about the predictors of sustained remission for patients reaching remission. Using two independent cohorts, we aimed to evaluate the prevalence and predictors for sustained remission.

METHODS

The study cohort consisted of subjects with RA from the Brigham and Women's Hospital Rheumatoid Arthritis Sequential Study (BRASS) and the Korean Observational Study Network for Arthritis (KORONA). We analyzed subjects who reached remission in 2009 with follow up data for two consecutive years. Remission was defined by the Disease Activity Score 28- (DAS28-CRP) of less than 2.6. Sustained remission was defined as three consecutive annual visits in remission. Predictors for sustained remission were identified by multivariate logistic regression analysis.

RESULTS

A total of 465 subjects were in remission in 2009. Sustained remission was achieved by 53 of 92 (57.5%) in BRASS and by 198 of 373 (53.1%) in KORONA. In multivariate analyses, baseline predictors of sustained remission were: disease duration less than 5 years [odds ratio (OR) 1.96, 95% confidence interval (95% CI) 1.08-3.58], Modified Health Assessment Questionnaire (MHAQ) score of 0 (OR 1.80, 95% CI 1.18-2.74), and non-use of oral glucocorticoid (OR 1.58, 95% CI 1.01-2.47).

CONCLUSION

More than half of RA subjects in remission in 2009 remained in remission through 2011. Short disease duration, no disability, and non-use of oral glucocorticoid at baseline were associated with sustained remission.