Use of the Bath Ankylosing Spondylitis Disease Activity Index in Patients With Psoriatic Arthritis With and Without Axial Disease.

OBJECTIVE: To evaluate whether the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) is a responsive instrument in psoriatic arthritis (PsA) and whether it differentiates between axial and peripheral disease activity in PsA. METHODS: Individuals with PsA initiating therapy in a longitudinal cohort study based in the United States were included. Axial PsA (axPsA), most often also associated with peripheral disease, was defined as fulfillment of the Assessment of Spondyloarthritis international Society axial spondyloarthritis classification criteria or presence of axial disease imaging features. Baseline BASDAI, individual BASDAI items, patient global assessment, patient pain, and Routine Assessment of Patient Index Data 3, and score changes following therapy initiation were descriptively reported. Standardized response means (SRMs) were calculated as the mean change divided by the SD of the change. RESULTS: The mean (SD) baseline BASDAI score at the time of therapy initiation was 5.0 (2.2) among those with axPsA (n = 40) and 4.8 (2.0) among those with peripheral-only disease (n = 79). There was no significant difference in patient-reported outcome scores between the groups. The mean change for BASDAI was similar among axial vs peripheral disease (-0.75 vs -0.83). SRMs were similar across axial vs peripheral disease for BASDAI (-0.37 vs -0.44) and the individual BASDAI items. CONCLUSION: BASDAI has reasonable responsiveness in PsA but does not differentiate between axPsA and peripheral PsA. (ClinicalTrials.gov: NCT03378336).

Which Educational Topics and Smartphone App Functions Are Prioritized by US Patients With Rheumatic and Musculoskeletal Diseases? A Mixed-Methods Study.

OBJECTIVE: We sought to identify (1) what types of information US adults with rheumatic and musculoskeletal diseases (RMD) perceive as most important to know about their disease, and (2) what functions they would use in an RMD-specific smartphone app. METHODS: Nominal groups with patients with RMD were conducted using online tools to generate a list of needed educational topics. Based on nominal group results, a survey with final educational items was administered online, along with questions about desired functions of a smartphone app for RMD and wearable use, to patients within a large community rheumatology practice-based research network and the PatientSpot registry. Chi-square tests and multivariate regression models were used to determine differences in priorities between groups of respondents with rheumatic inflammatory conditions (RICs) and osteoarthritis (OA), and possible associations. RESULTS: At least 80% of respondents considered finding a rheumatologist, understanding tests and medications, and quickly recognizing and communicating symptoms to doctors as extremely important educational topics. The highest-ranked topic for both RIC and OA groups was "knowing when the medication is not working." The app functions that most respondents considered useful were viewing laboratory results, recording symptoms to share with their rheumatology provider, and recording symptoms (eg, pain, fatigue) or disease flares for health tracking over time. Approximately one-third of respondents owned and regularly used a wearable activity tracker. CONCLUSION: People with RMD prioritized information about laboratory test results, medications, and disease and symptom monitoring, which can be used to create educational and digital tools that support patients during their disease journey.

Change in gait speed and adverse outcomes in patients with idiopathic pulmonary fibrosis: A prospective cohort study.

BACKGROUND AND OBJECTIVE: Gait speed is associated with survival in individuals with idiopathic pulmonary fibrosis (IPF). The extent to which four-metre gait speed (4MGS) decline predicts adverse outcome in IPF remains unclear. We aimed to examine longitudinal 4MGS change and identify a cut-point associated with adverse outcome. METHODS: In a prospective cohort study, we recruited 132 individuals newly diagnosed with IPF and measured 4MGS change over 6 months. Death/first hospitalization at 6 months were composite outcome events. Complete data (paired 4MGS plus index event) were available in 85 participants; missing 4MGS data were addressed using multiple imputation. Receiver-Operating Curve plots identified a 4MGS change cut-point. Cox proportional-hazard regression assessed the relationship between 4MGS change and time to event. RESULTS: 4MGS declined over 6 months (mean [95% CI] change: -0.05 [-0.09 to -0.01] m/s; p = 0.02). A decline of 0.07 m/s or more in 4MGS over 6 months had better discrimination for the index event than change in 6-minute walk distance, forced vital capacity, Composite Physiologic Index or Gender Age Physiology index. Kaplan-Meier curves demonstrated a significant difference in time to event between 4MGS groups (substantial decline: >-0.07 m/s versus minor decline/improvers: ≤-0.07 m/s; p = 0.007). Those with substantial decline had an increased risk of hospitalization/death (adjusted hazard ratio [95% CI] 4.61 [1.23-15.83]). Similar results were observed in multiple imputation analysis. CONCLUSION: In newly diagnosed IPF, a substantial 4MGS decline over 6 months is associated with shorter time to hospitalization/death at 6 months. 4MGS change has potential as a surrogate endpoint for interventions aimed at modifying hospitalization/death.

Tumor necrosis factor inhibitor (TNFi) persistence and reasons for discontinuation in a predominantly male cohort with axial spondyloarthritis.

Although tumor necrosis factor inhibitors (TNFi) have favorably altered the treatment landscape for patients with axial spondyloarthritis (axSpA), there is limited data regarding TNFi persistence and reasons for discontinuation. This is an observational time-to-event study utilizing data collected for a prospective multiple-disease registry of US Veterans with axSpA treated with TNFi therapies and recruited over a 10 year period. Clinical, serological, and comorbid parameters were collected. Corporate Data Warehouse Pharmacy files provided courses of the 5 TNFi agents, and response to treatment was documented. Individual TNFi persistence was established utilizing univariate and multivariate Cox proportional models, and reasons for discontinuation were obtained by physician chart review. Two-hundred and fifty-five axSpA patients received 731 TNFi courses. A majority of patients (84.3%) had TNFi persistence at 12 months; 63.5% and 47.1% at 24 and 36 months, respectively. Compared to adalimumab, infliximab demonstrated greater persistence, certolizumab the least. Age, smoking status, BMI, comorbidity burden, inflammatory markers and HLA-B27 did not predict TNFi persistence or discontinuation. Stroke and peripheral arterial disease increased the probability of TNFi discontinuation. Secondary non-response (SNR) was the most common reason for discontinuation (46% of all courses); non-adherence (6%) and clinical remission (2%) were uncommon. Pain score at enrollment, myocardial infarction, African American race and inflammatory bowel disease (IBD) predicted TNFi response. While initial persistence of TNFi treatment was high, a large proportion of the patients discontinued initial TNFi therapy by 3 years, primarily due to loss of efficacy. While further research identifying potential predictors of TNFi discontinuation in axSpA is warranted, access to alternate disease-modifying therapies is needed.

Digital habits of pulmonary rehabilitation service-users following the COVID-19 pandemic.

OBJECTIVE: We previously demonstrated low levels of digital literacy amongst pulmonary rehabilitation service-users prior to the COVID-19 pandemic. We aimed to identify whether the pandemic accelerated digital literacy in this population, resulting in greater acceptance of remote web-based pulmonary rehabilitation programme models. METHODS: We surveyed digital access and behaviours and pulmonary rehabilitation delivery preferences of service-users referred to pulmonary rehabilitation in 2021 (cohort 2021) and propensity score-matched them to a cohort who completed the survey in 2020 (cohort 2020). RESULTS: There were indicators that digital access and confidence were better amongst the Cohort 2021 but no difference was seen in the proportion of patients choosing remote web-based pulmonary rehabilitation as an acceptable method of receiving pulmonary rehabilitation. CONCLUSION: In an unselected cohort of service-users, remote web-based pulmonary rehabilitation was considered acceptable in only a minority of patients which has implications on healthcare commissioning and delivery of pulmonary rehabilitation.

COPD discharge bundle and pulmonary rehabilitation referral and uptake following hospitalisation for acute exacerbation of COPD.

Pulmonary rehabilitation (PR) following hospitalisations for acute exacerbation of COPD (AECOPD) is associated with improved exercise capacity and quality of life, and reduced readmissions. However, referral for, and uptake of, post-hospitalisation PR are low. In this prospective cohort study of 291 consecutive hospitalisations for AECOPD, COPD discharge bundles delivered by PR practitioners compared with non-PR practitioners were associated with increased PR referral (60% vs 12%, p<0.001; adjusted OR: 14.46, 95% CI: 5.28 to 39.57) and uptake (40% vs 32%, p=0.001; adjusted OR: 8.60, 95% CI: 2.51 to 29.50). Closer integration between hospital and PR services may increase post-hospitalisation PR referral and uptake.

Gait speed and adverse outcomes following hospitalised exacerbation of COPD.

BACKGROUND: The 4-m gait speed (4MGS) test is a simple physical performance measure and surrogate marker of frailty that is associated with adverse outcomes in older adults. We aimed to assess the ability of 4MGS to predict prognosis in patients hospitalised with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). METHODS: 213 participants hospitalised with AECOPD (52% male, mean age 72 years and mean forced expiratory volume in 1 s (FEV1) 35% predicted) were enrolled. 4MGS and baseline demographics were recorded at hospital discharge. All-cause readmission and mortality were collected for 1 year after discharge and multivariable Cox proportional hazards regressions were performed. Kaplan-Meier and competing risks analyses were conducted comparing time to all-cause readmission and mortality between 4MGS quartiles. RESULTS: 111 participants (52%) were readmitted and 35 (16%) died during the follow-up period. 4MGS was associated with all-cause readmission, with an adjusted subdistribution hazard ratio of 0.868 (95% CI 0.797-0.945; p=0.001) per 0.1 m·s-1 increase in gait speed, and with all-cause mortality, with an adjusted subdistribution hazard ratio of 0.747 (95% CI 0.622-0.898; p=0.002) per 0.1 m·s-1 increase in gait speed. Readmission and mortality models incorporating 4MGS had higher discrimination than age or FEV1 % pred alone, with areas under the receiver operator characteristic curves of 0.73 and 0.80, respectively. Kaplan-Meier and competing risks curves demonstrated that those in slower gait speed quartiles had reduced time to readmission and mortality (log-rank, both p<0.001). CONCLUSIONS: 4MGS provides a simple means of identifying at-risk patients with COPD at hospital discharge. This provides valuable information to plan post-discharge care and support.

A comparison of physical function instruments in psoriatic arthritis: HAQ-DI vs MDHAQ vs PROMIS10 global physical health.

OBJECTIVES: Physical function is a core outcome in PsA. We examined the construct validity and responsiveness of three commonly used instruments to assess physical function in PsA: HAQ disability index (HAQ-DI), MultiDimensional HAQ (MDHAQ) and the Patient-Reported Outcomes Measurement Information System (PROMIS®) Global-10. METHODS: Between 2016 and 2019, patients with PsA were enrolled in the Psoriatic Arthritis Research Consortium longitudinal cohort study in the USA. Correlations were calculated at baseline and among change scores using Spearman's correlation coefficient. Standardized response means were calculated. Agreement with the 20% improvement cut-off was used to determine the potential effect of using MDHAQ or the PROMIS Global-10 physical health (GPH) subscore in place of HAQ-DI when assessing the ACR20. RESULTS: A total of 274 patients were included in the analysis. The mean age of patients was 49 years and 51% were male. At baseline, the mean HAQ-DI was 0.6 (s.d. 0.6; range 0-3), the mean MDHAQ was 1.8 (s.d. 1.6; range 0-10) and the mean GPH T-score was 43.4 (s.d. 9.3; range 0-100). All three instruments were strongly correlated at baseline (rho 0.75-0.85). Change scores were moderately correlated (rho 0.42-0.71). Among therapy initiators, the mean change between two visits in HAQ-DI, MDHAQ and GPH was -0.1 (s.d. 0.4), -0.2 (s.d. 1.2) and 2.5 (s.d. 6.1), respectively. The standardized response means were 0.18, 0.16 and 0.41, respectively. CONCLUSION: The three instruments tested are not directly interchangeable but have overall similar levels of responsiveness.

The Effects of a Video Intervention on Posthospitalization Pulmonary Rehabilitation Uptake. A Randomized Controlled Trial.

Rationale: Pulmonary rehabilitation (PR) after hospitalizations for exacerbations of chronic obstructive pulmonary disease (COPD) improves exercise capacity and health-related quality of life and reduces readmissions. However, posthospitalization PR uptake is low. To date, no trials of interventions to increase uptake have been conducted.Objectives: To study the effect of a codesigned education video as an adjunct to usual care on posthospitalization PR uptake.Methods: The present study was an assessor- and statistician-blinded randomized controlled trial with nested, qualitative interviews of participants in the intervention group. Participants hospitalized with COPD exacerbations were assigned 1:1 to receive either usual care (COPD discharge bundle including PR information leaflet) or usual care plus the codesigned education video delivered via a handheld tablet device at discharge. Randomization used minimization to balance age, sex, FEV1 % predicted, frailty, transport availability, and previous PR experience.Measurements and Main Results: The primary outcome was PR uptake within 28 days of hospital discharge. A total of 200 patients were recruited, and 196 were randomized (51% female, median FEV1% predicted, 36 [interquartile range, 27-48]). PR uptake was 41% and 34% in the usual care and intervention groups, respectively (P = 0.37), with no differences in secondary (PR referral and completion) or safety (readmissions and death) endpoints. A total of 6 of the 15 participants interviewed could not recall receiving the video.Conclusions: A codesigned education video delivered at hospital discharge did not improve posthospitalization PR uptake, referral, or completion.

Clinical Manifestations and Diagnosis of Axial Spondyloarthritis.

BACKGROUND: Axial spondyloarthritis (axSpA) is a chronic, rheumatic disease characterized by inflammation of the sacroiliac joint, spine, and entheses. Axial spondyloarthritis affects up to 1.4% of adults in the United States and is associated with decreased quality of life, increased mortality, and substantial health care-related costs, imposing a high burden on patients, their caregivers, and society. SUMMARY OF WORK: Diagnosing axSpA can be difficult. In this review, we seek to help rheumatologists in recognizing and diagnosing axSpA. MAJOR CONCLUSIONS: A discussion of challenges associated with diagnosis is presented, including use and interpretation of imaging, reasons for diagnostic delays, differences in disease presentation by sex, and differential diagnoses of axSpA. FUTURE RESEARCH DIRECTIONS: The early diagnosis of axSpA and advances in available therapeutic options have improved patient care and disease management, but delays in diagnosis and treatment remain common. Additional research and education are critical for recognizing diverse axSpA presentations and optimizing management early in the course of disease.

Expert consensus on the operation of an adult tertiary intellectual disability mental health service in New South Wales, Australia.

OBJECTIVE: To identify and reach consensus on the priorities and operation of an adult tertiary intellectual disability mental health service in New South Wales, Australia. METHOD: An online Delphi consultation was conducted with 25 intellectual disability mental health experts. RESULTS: Participants agreed that the service should involve a multidisciplinary team and accept people with an intellectual disability aged over 15 years with complex needs and/or atypical presentations. Agreed service roles included short-term assessment, diagnosis and treatment, providing high-level clinical advice, and capacity building. Endorsed principles and practical ways of working align with existing guidelines. CONCLUSIONS: This study describes experts' views on how an adult tertiary intellectual disability mental health service should operate in New South Wales. Further consultation is needed to determine the views of people with an intellectual disability and mental health staff.

Efficacy and safety of ixekizumab through 52 weeks in two phase 3, randomised, controlled clinical trials in patients with active radiographic axial spondyloarthritis (COAST-V and COAST-W).

OBJECTIVES: To investigate the efficacy and safety of ixekizumab for up to 52 weeks in two phase 3 studies of patients with active radiographic axial spondyloarthritis (r-axSpA) who were biological disease-modifying antirheumatic drug (bDMARD)-naive (COAST-V) or tumour necrosis factor inhibitor (TNFi)-experienced (COAST-W). METHODS: Adults with active r-axSpA were randomised 1:1:1:1 (n=341) to 80 mg ixekizumab every 2 (IXE Q2W) or 4 weeks (IXE Q4W), placebo (PBO) or 40 mg adalimumab Q2W (ADA) in COAST-V and 1:1:1 (n=316) to IXE Q2W, IXE Q4W or PBO in COAST-W. At week 16, patients receiving ixekizumab continued their assigned treatment; patients receiving PBO or ADA were rerandomised 1:1 to IXE Q2W or IXE Q4W (PBO/IXE, ADA/IXE) through week 52. RESULTS: In COAST-V, Assessment of SpondyloArthritis international Society 40 (ASAS40) responses rates (intent-to-treat population, non-responder imputation) at weeks 16 and 52 were 48% and 53% (IXE Q4W); 52% and 51% (IXE Q2W); 36% and 51% (ADA/IXE); 19% and 47% (PBO/IXE). Corresponding ASAS40 response rates in COAST-W were 25% and 34% (IXE Q4W); 31% and 31% (IXE Q2W); 14% and 39% (PBO/IXE). Both ixekizumab regimens sustained improvements in disease activity, physical function, objective markers of inflammation, QoL, health status and overall function up to 52 weeks. Safety through 52 weeks of ixekizumab was consistent with safety through 16 weeks. CONCLUSION: The significant efficacy demonstrated with ixekizumab at week 16 was sustained for up to 52 weeks in bDMARD-naive and TNFi-experienced patients. bDMARD-naive patients initially treated with ADA demonstrated further numerical improvements after switching to ixekizumab. Safety findings were consistent with the known safety profile of ixekizumab. TRIAL REGISTRATION NUMBER: NCT02696785/NCT02696798.

Digital habits of PR service-users: Implications for home-based interventions during the COVID-19 pandemic.

Remote models of pulmonary rehabilitation (PR) are vital with suspension of face-to-face activity during the COVID-19 pandemic. We surveyed digital access and behaviours and PR delivery preferences of current PR service users. There was significant heterogeneity in access to and confidence in using the Internet with 31% having never previously accessed the Internet, 48% confident using the Internet and 29% reporting no interest in accessing any component of PR through a Web-based app. These data have implications for the remote delivery of PR during the COVID-19 pandemic and raise questions about the current readiness of service users to adopt Web-based delivered models of PR.

Anxiety and depression in bronchiectasis: Response to pulmonary rehabilitation and minimal clinically important difference of the Hospital Anxiety and Depression Scale.

The aims of the study were to evaluate the responsiveness of Hospital Anxiety and Depression Scale-Anxiety (HADS-A) subscale and HADS-Depression (HADS-D) subscale to pulmonary rehabilitation (PR) in patients with bronchiectasis compared to a matched group of patients with chronic obstructive pulmonary disease (COPD) and provide estimates of the minimal clinically important difference (MCID) of HADS-A and HADS-D in bronchiectasis. Patients with bronchiectasis and at least mild anxiety or depression (HADS-A ≥ 8 or/and HADS-D ≥ 8), as well as a propensity score-matched control group of patients with COPD, underwent an 8-week outpatient PR programme (two supervised sessions per week). Within- and between-group changes were calculated in response to PR. Anchor- and distribution-based methods were used to estimate the MCID. HADS-A and HADS-D improved in response to PR in both patients with bronchiectasis and those with COPD (median (25th, 75th centile)/mean (95% confidence interval) change: HADS-A change: bronchiectasis -2 (-5, 0), COPD -2 (-4, 0); p = 0.43 and HADS-D change: bronchiectasis -2 (-2 to -1), COPD -2 (-3 to -2); p = 0.16). Using 26 estimates, the MCID for HADS-A and HADS-D was -2 points. HADS-A and HADS-D are responsive to PR in patients with bronchiectasis and symptoms of mood disorder, with an MCID estimate of -2 points.

Application of machine learning in the diagnosis of axial spondyloarthritis.

PURPOSE OF REVIEW: In this review article, we describe the development and application of machine-learning models in the field of rheumatology to improve the detection and diagnosis rates of underdiagnosed rheumatologic conditions, such as ankylosing spondylitis and axial spondyloarthritis (axSpA). RECENT FINDINGS: In an attempt to aid in the earlier diagnosis of axSpA, we developed machine-learning models to predict a diagnosis of ankylosing spondylitis and axSpA using administrative claims and electronic medical record data. Machine-learning algorithms based on medical claims data predicted the diagnosis of ankylosing spondylitis better than a model developed based on clinical characteristics of ankylosing spondylitis. With additional clinical data, machine-learning algorithms developed using electronic medical records identified patients with axSpA with 82.6-91.8% accuracy. These two algorithms have helped us understand potential opportunities and challenges associated with each data set and with different analytic approaches. Efforts to refine and validate these machine-learning models are ongoing. SUMMARY: We discuss the challenges and benefits of machine-learning models in healthcare, along with potential opportunities for its application in the field of rheumatology, particularly in the early diagnosis of axSpA and ankylosing spondylitis.

Home versus outpatient pulmonary rehabilitation in COPD: a propensity-matched cohort study.

Home-based exercise has been proposed as an equivalent treatment strategy to supervised outpatient pulmonary rehabilitation (PR), but it is not known whether its implementation into clinical practice produces similar benefits to those observed in trials. We compared the real-world responses of 154 patients with COPD undergoing home-based exercise with a matched group attending supervised PR. We observed smaller improvements in exercise capacity with home-based exercise compared with PR, but similar improvements in quality of life. We propose that supervised PR remains the standard of care, with home-based exercise a less effective alternative for those unable to attend PR.

King's Brief Interstitial Lung Disease questionnaire: responsiveness and minimum clinically important difference.

Health status is increasingly used in clinical practice to quantify symptom burden and as a clinical trial end-point in patients with interstitial lung disease (ILD). The King's Brief Interstitial Lung Disease (KBILD) questionnaire is a brief, validated 15-item, disease-specific, health-related quality of life questionnaire that is increasingly used in clinical trials, but little data exist regarding the minimum clinically important difference (MCID). Using pulmonary rehabilitation as a model, we aimed to determine the responsiveness of KBILD and provide estimates of the MCID.KBILD scores, Chronic Respiratory Questionnaire (CRQ) scores, Medical Research Council (MRC) Dyspnoea score and incremental shuttle walk test (ISWT) distance were measured in 209 patients with ILD (105 with idiopathic pulmonary fibrosis (IPF)) before and after an outpatient pulmonary rehabilitation programme. Changes with intervention and Cohen's effect size were calculated. Anchor-based (linear regression and receiver operating characteristic plots) or distribution-based approaches (0.5 sd and standard error of measurement) were used to estimate the MCID of KBILD domain and total scores.KBILD, CRQ, MRC Dyspnoea and ISWT improved with intervention, and the effect sizes of KBILD domain and total scores ranged from 0.28 to 0.38. Using anchor-based estimates, the MCID estimates for KBILD-Psychological, KBILD-Breathlessness and activities, and KBILD-Total were 5.4, 4.4 and 3.9 points, respectively. Using distribution-based methods, the MCID estimate for KBILD-Chest symptoms was 9.8 points. The MCID estimates for KBILD in IPF patients were similar.In patients with ILD and IPF, KBILD is responsive to intervention with an estimated MCID of 3.9 points for the total score.

Genome-wide DNA methylation analysis in ankylosing spondylitis identifies HLA-B*27 dependent and independent DNA methylation changes in whole blood.

BACKGROUND AND OBJECTIVE: Ankylosing spondylitis is a chronic inflammatory disease characterized by inflammation of the sacroiliac joints and the spine that can lead to significant pain, immobility, and disability. The etiology and pathogenesis of ankylosing spondylitis are incompletely understood, though most patients carry the HLA-B*27 allele. The objective of this study was to evaluate DNA methylation changes in ankylosing spondylitis with the goal of revealing novel mechanistic insights into this disease. METHODS: Genome-wide DNA methylation analysis was performed in whole blood DNA samples using the Infinium MethylationEPIC array in patients with ankylosing spondylitis compared to age, sex, and race matched patients with osteoarthritis as a non-inflammatory disease control. We studied 24 patients with ankylosing spondylitis, including 12 patients who carry HLA-B*27 and 12 patients who are HLA-B*27 negative. DNA methylation analysis was performed with adjustment for blood cell composition in each sample. RESULTS: We identified a total of 67 differentially methylated sites between ankylosing spondylitis patients and osteoarthritis controls. Hypermethylated genes found included GTPase-related genes, while hypomethylated genes included HCP5, which encodes a lncRNA within the MHC region, previously associated with genetic risk for psoriasis and toxic epidermal necrolysis. Carrying HLA-B*27 was associated with robust hypomethylation of HCP5, tubulin folding cofactor A (TBCA) and phospholipase D Family Member 6 (PLD6) in ankylosing spondylitis patients. Hypomethylation within HCP5 involves a CpG site that contains a single nucleotide polymorphism in linkage disequilibrium with HLA-B*27 and that controls DNA methylation at this locus in an allele-specific manner. CONCLUSIONS: A genome-wide DNA methylation analysis in ankylosing spondylitis identified DNA methylation patterns that could provide potential novel insights into this disease. Our findings suggest that HLA-B*27 might play a role in ankylosing spondylitis in part through inducing epigenetic dysregulation.

Cohort identification of axial spondyloarthritis in a large healthcare dataset: current and future methods.

BACKGROUND: Big data research is important for studying uncommon diseases in real-world settings. Most big data studies in axial spondyloarthritis (axSpA) have been limited to populations identified with billing codes for ankylosing spondylitis (AS). axSpA is a more inclusive concept, and reliance on AS codes does not produce a comprehensive axSpA study population. The first objective was to describe our process for establishing an appropriate sample of patients with and without axSpA for developing accurate axSpA identification methods. The second objective was to determine the classification performance of AS billing codes against the chart-reviewed axSpA reference standard. METHODS: Veteran Health Affairs clinical and administrative data, between January 2005 and June 2015, were used to randomly select patients with clinical phenotypes that represented high, moderate, and low likelihoods of an axSpA diagnosis. With chart review, the sampled patients were classified as Yes axSpA, No axSpA or Uncertain axSpA, and these classification assignments were used as the reference standard for determining the positive predictive value (PPV) and sensitivity of AS ICD-9 codes for axSpA. RESULTS: Six hundred patients were classified as Yes axSpA (26.8%), No axSpA (68.3%), or Uncertain axSpA (4.8%). The PPV and sensitivity of an AS ICD-9 code for axSpA were 83.3% and 57.3%, respectively. CONCLUSIONS: Standard methods of identifying axSpA patients in a large dataset lacked sensitivity. An appropriate sample of patients with and without axSpA was established and characterized for developing novel axSpA identification methods that are anticipated to enable previously impractical big data research.