Objective: In this study, we aimed to investigate the incidence and risk factors for interstitial nephritis in patients with ankylosing spondylitis (AS). Methods: We retrospectively analyzed the claims records of patients diagnosed with AS in Korea’s Health Insurance Review and Assessment Service Database between 2016 and 2019. The Assessment of Spondyloarthritis International Society nonsteroidal anti-inflammatory drugs (NSAIDs) intake score was used to calculate the NSAID dosage over 1 year after AS diagnosis. The incidence rate of interstitial kidney disease was calculated as the number of events per 1,000 person-years. The risks associated with sex, age, Charlson Comorbidity Index, comorbidities, and concomitant medications were assessed using the Cox proportional hazards model, with results presented as hazard ratios (HRs) and 95% confidence intervals (CIs). Results: In total, 11,749 patients with AS were included in this study. Of these, 79 patients had interstitial nephritis, with an incidence rate of 2.50 per 1,000 person-years. In multivariable analysis, female sex (HR, 2.44; 95% CI, 1.56~3.83), hypertension (HR, 2.08; 95% CI, 1.15~3.76), and renal failure (HR, 3.70; 95% CI, 1.30~10.55) showed significant associations. However, NSAID use in the first year after AS diagnosis was not associated with interstitial nephritis occurrence. Conclusion The incidence of interstitial nephritis in patients with AS was 2.50 per 1,000 person-years, with female sex and comorbidities identified as significant risk factors. However, NSAID use during the first year after AS diagnosis was not associated with interstitial nephritis development.

Background/Aims: Exercise is a key component of the management of axial spondyloarthritis (axSpA), providing symptomatic relief and helping prevent ankylosis. However, there is a lack of quantitative studies evaluating daily exercise patterns in patients with axSpA. This study assessed the types, frequency, and duration of exercises performed by these patients through a structured questionnaire. Methods: This cross-sectional study included radiographic axSpA patients who visited a rheumatology clinic between September 2014 and March 2016 and provided informed consent to participate. The survey captured information on four types of exercise: high-intensity exercise, moderate-intensity exercise, strength training, and walking. Disease activity and functional status were evaluated using the Bath ankylosing spondylitis disease activity index (BASDAI) and the Bath ankylosing spondylitis functional index (BASFI), respectively. Results: A total of 645 patients participated in the study. Among them, 25.1% engaged in high-intensity exercise, 36.0% in moderate-intensity exercise, 81.2% in walking, and 32.8% in strength training. The median weekly exercise frequency was 3.0 days (interquartile range [IQR], 2.0-4.0) for high-intensity exercise, 3.0 days (IQR, 2.0-5.0) for moderate-intensity exercise, 5.5 days (IQR, 4.0-7.0) for walking, and 3.0 days (IQR, 2.0-5.0) for strength training. The median daily exercise duration was 60 minutes (IQR, 60-120) for high-intensity exercise, 60 minutes (IQR, 30-90) for moderate-intensity exercise, 30 minutes (IQR, 20-60) for walking, and 30 minutes (IQR, 20-60) for strength training. Comparisons by disease activity showed that BASFI scores were more strongly associated with differences in exercise patterns than BASDAI scores. Conclusion Radiographic axSpA patients predominantly engaged in low-intensity activities, particularly walking, typically for short durations. Given the observed variations in exercise patterns based on disease activity, personalized exercise education and guidance should be prioritized in clinical practice to optimize axSpA management.

Background/Aims: Exercise is a key component of the management of axial spondyloarthritis (axSpA), providing symptomatic relief and helping prevent ankylosis. However, there is a lack of quantitative studies evaluating daily exercise patterns in patients with axSpA. This study assessed the types, frequency, and duration of exercises performed by these patients through a structured questionnaire. Methods: This cross-sectional study included radiographic axSpA patients who visited a rheumatology clinic between September 2014 and March 2016 and provided informed consent to participate. The survey captured information on four types of exercise: high-intensity exercise, moderate-intensity exercise, strength training, and walking. Disease activity and functional status were evaluated using the Bath ankylosing spondylitis disease activity index (BASDAI) and the Bath ankylosing spondylitis functional index (BASFI), respectively. Results: A total of 645 patients participated in the study. Among them, 25.1% engaged in high-intensity exercise, 36.0% in moderate-intensity exercise, 81.2% in walking, and 32.8% in strength training. The median weekly exercise frequency was 3.0 days (interquartile range [IQR], 2.0-4.0) for high-intensity exercise, 3.0 days (IQR, 2.0-5.0) for moderate-intensity exercise, 5.5 days (IQR, 4.0-7.0) for walking, and 3.0 days (IQR, 2.0-5.0) for strength training. The median daily exercise duration was 60 minutes (IQR, 60-120) for high-intensity exercise, 60 minutes (IQR, 30-90) for moderate-intensity exercise, 30 minutes (IQR, 20-60) for walking, and 30 minutes (IQR, 20-60) for strength training. Comparisons by disease activity showed that BASFI scores were more strongly associated with differences in exercise patterns than BASDAI scores. Conclusion Radiographic axSpA patients predominantly engaged in low-intensity activities, particularly walking, typically for short durations. Given the observed variations in exercise patterns based on disease activity, personalized exercise education and guidance should be prioritized in clinical practice to optimize axSpA management.

Background/Aims: Exercise is a key component of the management of axial spondyloarthritis (axSpA), providing symptomatic relief and helping prevent ankylosis. However, there is a lack of quantitative studies evaluating daily exercise patterns in patients with axSpA. This study assessed the types, frequency, and duration of exercises performed by these patients through a structured questionnaire. Methods: This cross-sectional study included radiographic axSpA patients who visited a rheumatology clinic between September 2014 and March 2016 and provided informed consent to participate. The survey captured information on four types of exercise: high-intensity exercise, moderate-intensity exercise, strength training, and walking. Disease activity and functional status were evaluated using the Bath ankylosing spondylitis disease activity index (BASDAI) and the Bath ankylosing spondylitis functional index (BASFI), respectively. Results: A total of 645 patients participated in the study. Among them, 25.1% engaged in high-intensity exercise, 36.0% in moderate-intensity exercise, 81.2% in walking, and 32.8% in strength training. The median weekly exercise frequency was 3.0 days (interquartile range [IQR], 2.0-4.0) for high-intensity exercise, 3.0 days (IQR, 2.0-5.0) for moderate-intensity exercise, 5.5 days (IQR, 4.0-7.0) for walking, and 3.0 days (IQR, 2.0-5.0) for strength training. The median daily exercise duration was 60 minutes (IQR, 60-120) for high-intensity exercise, 60 minutes (IQR, 30-90) for moderate-intensity exercise, 30 minutes (IQR, 20-60) for walking, and 30 minutes (IQR, 20-60) for strength training. Comparisons by disease activity showed that BASFI scores were more strongly associated with differences in exercise patterns than BASDAI scores. Conclusion Radiographic axSpA patients predominantly engaged in low-intensity activities, particularly walking, typically for short durations. Given the observed variations in exercise patterns based on disease activity, personalized exercise education and guidance should be prioritized in clinical practice to optimize axSpA management.

Background/Aims: Exercise is a key component of the management of axial spondyloarthritis (axSpA), providing symptomatic relief and helping prevent ankylosis. However, there is a lack of quantitative studies evaluating daily exercise patterns in patients with axSpA. This study assessed the types, frequency, and duration of exercises performed by these patients through a structured questionnaire. Methods: This cross-sectional study included radiographic axSpA patients who visited a rheumatology clinic between September 2014 and March 2016 and provided informed consent to participate. The survey captured information on four types of exercise: high-intensity exercise, moderate-intensity exercise, strength training, and walking. Disease activity and functional status were evaluated using the Bath ankylosing spondylitis disease activity index (BASDAI) and the Bath ankylosing spondylitis functional index (BASFI), respectively. Results: A total of 645 patients participated in the study. Among them, 25.1% engaged in high-intensity exercise, 36.0% in moderate-intensity exercise, 81.2% in walking, and 32.8% in strength training. The median weekly exercise frequency was 3.0 days (interquartile range [IQR], 2.0-4.0) for high-intensity exercise, 3.0 days (IQR, 2.0-5.0) for moderate-intensity exercise, 5.5 days (IQR, 4.0-7.0) for walking, and 3.0 days (IQR, 2.0-5.0) for strength training. The median daily exercise duration was 60 minutes (IQR, 60-120) for high-intensity exercise, 60 minutes (IQR, 30-90) for moderate-intensity exercise, 30 minutes (IQR, 20-60) for walking, and 30 minutes (IQR, 20-60) for strength training. Comparisons by disease activity showed that BASFI scores were more strongly associated with differences in exercise patterns than BASDAI scores. Conclusion Radiographic axSpA patients predominantly engaged in low-intensity activities, particularly walking, typically for short durations. Given the observed variations in exercise patterns based on disease activity, personalized exercise education and guidance should be prioritized in clinical practice to optimize axSpA management.

Objective: Ankylosing spondylitis (AS) is chronic inflammatory arthritis causing structural damage and radiographic progression to the spine due to repeated and continuous inflammation over a long period. This study establishes the application of machine learning models to predict radiographic progression in AS patients using time-series data from electronic medical records (EMRs). Methods: EMR data, including baseline characteristics, laboratory findings, drug administration, and modified Stoke AS Spine Score (mSASSS), were collected from 1,123 AS patients between January 2001 and December 2018 at a single center at the time of first (T1 ), second (T2 ), and third (T3 ) visits. The radiographic progression of the (n+1)th visit (Pn+1 =(mSASSSn+1 –mSASSSn )/(Tn+1 – Tn )≥1 unit per year) was predicted using follow-up visit datasets from T1 to Tn . We used three machine learning methods (logistic regression with the least absolute shrinkage and selection operation, random forest, and extreme gradient boosting algorithms) with three-fold cross-validation. Results: The random forest model using the T1 EMR dataset best predicted the radiographic progression P2 among the machine learning models tested with a mean accuracy and area under the curves of 73.73% and 0.79, respectively. Among the T1 variables, the most important variables for predicting radiographic progression were in the order of total mSASSS, age, and alkaline phosphatase. Conclusion Prognosis predictive models using time-series data showed reasonable performance with clinical features of the first visit dataset when predicting radiographic progression.

Objective: To examine whether simple laboratory tests can guide selection between tocilizumab (TCZ) and tumor necrosis factor inhibitors (TNFi) in biologic-naive patients with rheumatoid arthritis (RA), by investigating their influence on drug retention. Methods: Data of RA patients prescribed TCZ or TNFi as the initial biologics from March 2013 to December 2021 were obtained from the KOrean College of Rheumatology BIOlogics and Targeted Therapy (KOBIO) registry. Propensity score matching was performed to adjust for baseline confounding factors. Hazards of drug discontinuation for TCZ were calculated compared to those for TNFi. Interaction analyses with a Bonferroni-corrected p-value threshold were conducted to determine whether the hemoglobin level, C-reactive protein level, erythrocyte sedimentation rate, and platelet count affected the hazards of drug discontinuation. Results: Overall, 893 patients were analyzed, of whom 315 and 578 were treated with TCZ and TNFi, respectively. The hazards of drug discontinuation in all patients were lower for TCZ than for TNFi (hazard ratio [HR]: 0.53, 95% confidence interval [CI]:0.44~0.66). Notably, only the presence of anemia indicated a significant interaction (p for interaction=0.010); the HRs for drug discontinuation were 0.41 (95% CI: 0.30~0.55) and 0.70 (95% CI: 0.53~0.92) in the anemic and non-anemic groups, respectively.In the anemic subgroup, biologics were discontinued because of a lack of efficacy in 35.0% of TNFi initiators and 7.4% of TCZ initiators. Conclusion The drug discontinuation rate in biologic-naïve patients with RA was significantly lower for TCZ than for TNFi, particularly in those with anemia.