Discriminant validity, responsiveness and reliability of the arthritis-specific Work Productivity Survey assessing workplace and household productivity within and outside the home in patients with axial spondyloarthritis, including nonradiographic axial spondyloarthritis and ankylosing spondylitis

Measuring, Analyzing, and Presenting Work Productivity Loss in Randomized Controlled Trials: A Scoping Review

OBJECTIVES

This study aimed to conduct a scoping review of randomized controlled trials (RCTs) and investigate which work productivity loss outcomes were measured in these RCTs, how each outcome was measured and analyzed, and how the results for each outcome were presented.

METHODS

A systematic search was conducted from January 2010 to April 2020 from 2 databases: PubMed and Cochrane Central Register of Controlled Trials. Data on country, study population, disease focus, sample size, work productivity loss outcomes measured (absenteeism, presenteeism, employment status changes), and methods used to measure, report, and analyze each work productivity loss outcome were extracted and analyzed.

RESULTS

We found 435 studies measuring absenteeism or presenteeism, of which 155 studies (35.6%) measured both absenteeism and presenteeism and were included in our final review. Only 9 studies also measured employment status changes. The most used questionnaire was the Work Productivity and Activity Impairment Questionnaire. The analysis of absenteeism and presenteeism data was mostly done using regression models (n = 98, n = 98, respectively) for which a normal distribution was assumed (n = 77, n = 89, respectively). Absenteeism results were most often presented in time whereas presenteeism was commonly presented using a percent scale or score.

CONCLUSIONS

There is a lack of consensus on how to measure, analyze, and present work productivity loss outcomes in RCTs published in the past 10 years. The diversity of measurement, analysis, and presentation methods used in RCTs may make comparability challenging. There is a need for guidelines providing recommendations to standardize the comprehensiveness and the appropriateness of methods used to measure, analyze, and report work productivity loss in RCTs.

Induction of Sustained Clinical Remission in Early Axial Spondyloarthritis Following Certolizumab Pegol Treatment: 48-Week Outcomes from C-OPTIMISE

INTRODUCTION

Achievement of remission is a key treatment goal for patients with axial spondyloarthritis (axSpA). C-OPTIMISE assessed achievement of sustained clinical remission in patients with axSpA, including radiographic (r) and non-radiographic (nr) axSpA, during certolizumab pegol (CZP) treatment, and subsequent maintenance of remission following CZP dose continuation, dose reduction or withdrawal. Here, we report outcomes from the first 48 weeks (induction period) of C-OPTIMISE, during which patients received open-label CZP.

METHODS

C-OPTIMISE (NCT02505542) was a two-part, multicenter, phase 3b study in adult patients with early axSpA (r-/nr-axSpA), including a 48-week open-label induction period followed by a 48-week maintenance period. Patients with active adult-onset axSpA, < 5 years' symptom duration, and fulfilling Assessment of SpondyloArthritis international Society classification criteria, were included. During the induction period, patients received a loading dose of CZP 400 mg at weeks 0, 2, and 4, followed by CZP 200 mg every 2 weeks (Q2W) up to week 48. The main outcome of the 48-week induction period was the achievement of sustained clinical remission (defined as an Ankylosing Spondylitis Disease Activity Score [ASDAS] < 1.3 at week 32 and < 2.1 at week 36 [or vice versa], and < 1.3 at week 48).

RESULTS

In total, 736 patients (407 with r-axSpA, 329 with nr-axSpA) were enrolled into the study. At week 48, 43.9% (323/736) of patients achieved sustained remission, including 42.8% (174/407) of patients with r-axSpA and 45.3% (149/329) with nr-axSpA. Patients also demonstrated substantial improvements in axSpA symptoms, MRI outcomes and quality of life measures. Adverse events occurred in 67.9% (500/736) of patients, of which 6.0% (44/736) were serious.

CONCLUSIONS

Over 40% of patients with early axSpA achieved sustained remission during 48 weeks of open-label CZP treatment. Additionally, patients across the axSpA spectrum demonstrated substantial improvements in imaging outcomes and quality of life following treatment. No new safety signals were identified.

TRIAL REGISTRATION

NCT02505542.

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.

Similar alteration for mental and physical aspects in health-related quality of life over 5 to 8 years in 1347 patients with early arthritis and early inflammatory back pain

Introduction

Health-related quality of life (HRQoL) is a priority for patients. The objectives were to describe the changes in HRQoL over 5–8 years in patients with early arthritis (EA) or early inflammatory back pain (IBP) and to explore factors associated to HRQoL.

Patients and methods

In 2 prospective observational French cohorts (ESPOIR for EA patients and DESIR for early IBP patients), HRQoL was assessed regularly over 5–8 years, using the SF36 physical and mental composite scores (PCS and MCS, range 0–100). Disease activity was assessed by DAS28-ESR and ASDAS-CRP. Univariate and multivariate linear mixed-effect models and trajectory-based mapping were applied.

Results

In all, 1347 patients (701 EA and 646 early IBP) were analysed: mean age 48.4 ± 12.2 and 33.9 ± 8.7 years respectively; mean disease duration 3.4 ± 1.7 and 18.2 ± 10.8 months; and 76.3% and 55.0% females. At baseline, in EA, mean PCS and MCS were respectively 40.2 ± 9.1 and 40.4 ± 11.2 and, in early IBP, were respectively 38.5 ± 8.5 and 39.8 ± 10.9. Over follow-up, HRQoL mean levels improved mostly over the first 6 months (p <  0.001). Two trajectories were evidenced in both diseases. The ‘good HRQoL’ trajectory groups, i.e. 54–61% of patients, reached levels of HRQoL close to population norms. DAS28-ESR and ASDAS-CRP over time were related to PCS (range of explained variance 9–43%, p <  0.001 in the mixed models) but not to MCS.

Conclusion

HRQoL was altered similarly for both physical and mental aspects in EA and early IBP. Disease activity only partly explained HRQoL: the drivers of HRQoL should be further explored.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1841-y) contains supplementary material, which is available to authorized users.

Assessing the Value of Sarilumab Monotherapy for Adults with Moderately to Severely Active Rheumatoid Arthritis: A Cost-Effectiveness Analysis

BACKGROUND

Rheumatoid arthritis is associated with a societal burden greater than $39 billion annually. Novel treatments, known as targeted immune modulators (TIMs), are expensive but effective, producing improvements in response rates compared with conventional disease-modifying antirheumatic drugs (cDMARDs). Sarilumab, a TIM approved in 2017, shows superior improvements compared with cDMARDs and produced significantly greater likelihood of achieving response and improvement in the Health Assessment Questionnaire Disability Index than adalimumab monotherapy. Although sarilumab monotherapy has shown improvements over cDMARDs and the TIM market leader adalimumab, treatment with sarilumab is costly, with an annual wholesale acquisition cost of $39,000.

OBJECTIVE

To estimate the lifetime cost-effectiveness of starting treatment with sarilumab monotherapy for adult patients with moderately to severely active rheumatoid arthritis who have had an inadequate response to cDMARDs.

METHODS

A sequential treatment cohort model followed a hypothetical cohort from initiation of sarilumab monotherapy until death. The model allowed patients to switch therapies up to 3 times due to effectiveness or adverse events. The first switch was to a TIM within the same treatment category; the second switch was to a TIM within a different treatment category; and the third switch was to a cDMARD. Sarilumab monotherapy was compared with a cDMARD (methotrexate) and the TIM market leader (adalimumab monotherapy). Key risk and benefit evidence came from clinical studies and network meta-analyses of data on radiographic progression and response. We used a lifetime time horizon and the U.S. health sector payer perspective assuming therapy net pricing. We also incorporated loss of productivity to reflect a restricted societal perspective.

RESULTS

Over a lifetime time horizon, a treatment pathway starting with sarilumab resulted in 17.16 life-years and 13.66 quality-adjusted life-years (QALYs). Treatment pathways starting with the cDMARD resulted in 16.54 life-years and 11.77 QALYs; treatment pathways starting with adalimumab resulted in 17.05 life-years and 13.35 QALYs. Total costs for sarilumab ($492,000 for payer perspective, $634,000 for societal perspective) were less than total costs for adalimumab ($536,000 for payer perspective, $689,000 for societal perspective) but higher than total costs for the cDMARD ($63,000 for payer perspective, $272,000 for societal perspective). When compared with cDMARD therapy, sarilumab resulted in a cost-effectiveness estimate of $227,000 per QALY gained from the payer perspective and $191,000 per QALYs gained from the societal perspective. When compared with adalimumab, sarilumab was dominant from both perspectives.

CONCLUSIONS

Sarilumab resulted in better health outcomes than conventional therapy alone. However, its additional cost with assumed class-level net prices led to cost-effectiveness estimates above commonly cited thresholds. When compared with the market leader, sarilumab achieved favorable value. This evaluation informs stakeholders of the value of sarilumab and its alternatives to promote high value practices in health care.

DISCLOSURES

Funding for this research was contributed by the Institute for Clinical and Economic Review (ICER). Ollendorf, Chapman, Kumar, Synnott, and Agboola are employees of ICER, an independent organization that evaluates the evidence on the value of health care interventions, which is funded by grants from the Laura and John Arnold Foundation, Blue Shield of California Foundation, and the California HealthCare Foundation. The organization's annual policy summit is supported by dues from Aetna, AHIP, Anthem, Blue Shield of California, CVS Caremark, Express Scripts, Harvard Pilgrim Health Care, Omeda Rx, United Healthcare, Kaiser Permanente, Premera Blue Cross, AstraZeneca, Genentech, GlaxoSmithKline, Johnson & Johnson, Merck, National Pharmaceutical Council, Takeda, Pfizer, Novartis, Lilly, and Humana. This work is an extension of an analysis presented at the New England Comparative Effectiveness Public Advisory Council on March 24, 2017, where the authors received public feedback on the analysis, results, and effect of a value assessment for targeted immune modulators. At the time of presentation, sarilumab was still an investigational product; therefore, a price was not known, so cost-effectiveness estimates were not generated. Since the presentation of that material, additional evidence for sarilumab has become available. The additional evidence has been incorporated into this analysis to present cost-effectiveness estimates for sarilumab.

Impact of adalimumab on clinical outcomes, healthcare resource utilization, and sick leave in patients with ankylosing spondylitis: an observational study from five Central and Eastern European countries

BACKGROUND

Patients with ankylosing spondylitis (AS) are substantial users of healthcare resources due to chronic and potentially disabling disease. This study assessed the impact of adalimumab on clinical outcomes, healthcare resource utilization, and sick leave in patients with AS in five Central and Eastern Europe (CEE) countries.

METHODS

This was an observational study in the routine clinical setting. Patients diagnosed with AS and starting treatment with originator adalimumab were followed for 12 months by assessing disease activity (Bath Ankylosing Spondylitis Disease Activity Index [BASDAI] and Ankylosing Spondylitis Disease Activity Score [ASDAS]) and physical function (Bath Ankylosing Spondylitis Functional Index [BASFI]). Data on healthcare resource utilization and sick leave were collected prospectively and compared with historical data before adalimumab initiation, as well as between treatment responders and non-responders defined by BASDAI-50.

RESULTS

The total effectiveness population comprised 450 patients with on average long-standing AS, high disease activity, and functional impairment. At 12 months of adalimumab therapy, mean ASDAS and BASFI scores were in the range of low disease activity and normal physical function, respectively. The mean number of hospital admissions, hospital inpatient days, and healthcare provider visits were decreased by 67.9, 83.0, and 46.3%, respectively. The number and length of sick leaves were decreased by 65.6 and 81.4%, respectively. Reductions were higher in treatment responders than non-responders.

CONCLUSION

Originator adalimumab in routine clinical practice in five CEE countries produced clinically meaningful improvements in disease activity and physical function, and it was associated with reductions in healthcare resource utilization and sick leave.

Patient Burden of Axial Spondyloarthritis

Axial spondyloarthritis (AxSpA) is an inflammatory spondyloarthritis (SpA) that has significant impact on a patient's life. Symptoms, including fatigue, sleep problems, depression, and sexual dysfunction, can profoundly impact health-related quality of life (HRQoL) and limit work, leisure, and daily activities. Available therapies effectively manage pain and inflammation in early-stage disease, but patients often continue to experience impaired HRQoL. Thus, there remains a need for new therapies with novel mechanisms that can stop disease progression, potentially reverse damage caused by AxSpA and improve HRQoL in patients with AxSpA. Newer biologic agents, such as those targeting the interleukin 17-interleukin 23 axis, have promising efficacy and may improve HRQoL for patients with AxSpA. The AxSpA has many negative effects on HRQoL. By targeting disease pathways responsible for the development of AxSpA, approved and emerging therapies potentially reduce disease activity and improve the functional status of patients with AxSpA. This narrative review reflects on the findings of studies evaluating HRQoL of individuals with AxSpA and the role of newer therapies.

Cost-effectiveness Analysis of Golimumab in the Treatment of Non-Radiographic Axial Spondyloarthritis in Scotland

INTRODUCTION

The aim of this study is to assess the cost-effectiveness of golimumab for the treatment of non-radiographic axial spondyloarthritis (nr-axSpA) vs. conventional therapy and other tumor necrosis factor inhibitors from the Scottish payer perspective.

METHODS

A model comprising a short-term decision tree and a long-term Markov model was developed to compare cost-effectiveness (incremental costs per quality-adjusted life-year [QALY]) for patients in Scotland with nr-axSpA treated by conventional therapy, adalimumab, certolizumab pegol, etanercept, or golimumab for a lifetime period. A network meta-analysis (NMA) was conducted to identify clinical and safety data for treatments and synthesize the available evidence into relative treatment effects between comparators. The probability of patients achieving an Assessment of SpondyloArthritis International Society 20/40% response criteria (ASAS20/ASAS40) or a 50% improvement in Bath Ankylosing Spondylitis Disease Activity Index score (BASDAI50) at week 12 was obtained from the NMA for each of the comparators. Baseline health state utilities were based on the EQ-5D questionnaire collected in the golimumab GO-AHEAD study. The cost of treatment was calculated based on drug acquisition, drug administration, and initiation/monitoring costs.

RESULTS

Golimumab resulted in an increase of 2.06 QALYs and additional cost of £39,770 compared with conventional therapy. Incremental cost per QALY gained was £19,280 for golimumab, which was lower than adalimumab (£19,737), etanercept (£20,089), and higher than certolizumab pegol (£18,710). Golimumab remained cost-effective throughout a range of sensitivity analyses where key assumptions were tested.

CONCLUSIONS

From a Scottish perspective, golimumab was a cost-effective treatment for nr-axSpA compared with conventional therapy at a willingness-to-pay threshold of £30,000 per QALY.

FUNDING

Merck & Co., Inc.

Improvements in workplace and household productivity with certolizumab pegol treatment in axial spondyloarthritis: results to week 96 of a phase III study

Objectives

To evaluate the effect of certolizumab pegol (CZP) on work and household productivity, and on participation in family, social and leisure activities in patients with axial spondyloarthritis (axSpA), including ankylosing spondylitis (AS) and non-radiographic (nr-) axSpA.

Methods

RAPID-axSpA (NCT01087762) was a phase III, double-blind, placebo-controlled trial to week (Wk) 24, dose-blind to Wk48 and open-label to Wk204. A total of 325 patients were randomised 1:1:1 to placebo, CZP 200 mg Q2W or CZP 400 mg Q4W. The validated arthritis-specific Work Productivity Survey assessed the impact of axSpA on work and household productivity and participation in social activities during the preceding month. Data are shown to Wk96, with responses compared between treatment arms (placebo vs CZP 200 mg and 400 mg dose groups combined) and subpopulations using a non-parametric bootstrap-t method.

Results

At baseline, 63.2% of placebo and 72.0% of CZP patients were employed. By Wk24, CZP patients reported on average 1.0 fewer days of absenteeism and 2.6 fewer days of presenteeism per month, compared with 0.4 and 0.9 fewer days for placebo. At home, by Wk24, CZP patients reported on average 3.0 household work days gained per month versus 1.3 for placebo. CZP patients reported fewer days with reduced household productivity or days lost for social participation. Similar improvements were observed in AS and nr-axSpA subpopulations and improvements with CZP were maintained to Wk96.

Conclusions

Compared with placebo, treatment with CZP significantly improved work and household productivity and resulted in greater social participation for patients with axSpA, which could lead to considerable indirect cost gains.

Trial registration number

NCT01087762.

Work disability in non-radiographic axial spondyloarthritis patients before and after start of anti-TNF therapy: a population-based regional cohort study from southern Sweden

Objective

The aim was to assess work-loss days before and after commencement of anti-TNF treatment in patients with non-radiographic axial spondylarthritis (nr-axSpA).

Methods

Bionaïve nr-axSpA patients (n = 75), aged 17-62 years, fulfilling the Assessment of SpondyloArthritis international Society criteria for axial spondyloarthritis and starting anti-TNF treatment during 2004-11, were retrieved from the observational South Swedish Arthritis Treatment Group study. Patient information was linked to Swedish Social Insurance Agency data on sick leave and disability pension from 1 year before to 2 years after anti-TNF initiation. Matched population references were included for comparison and to adjust for secular trends.

Results

The nr-axSpA patients had a median age of 35 years and disease duration of 6 years at the start of treatment. During the 2 years after anti-TNF initiation, mean work-loss days (including both sick leave and disability pension) in the nr-axSpA group decreased significantly from 3.4 to 1.9 times more than among the population references. The effect was seen on sick leave, whereas disability pension levels remained similar in both groups throughout.

Conclusion

Anti-TNF therapy in nr-axSpA was associated with a significant and sustained improvement of work disability over 2 years. However, the proportion of work-loss days remained almost twice as high as in the general population at the end of follow-up.

The health-related quality of life of ankylosing spondylitis patients assessed by SF-36: a systematic review and meta-analysis

PURPOSE

The main purpose of this meta-analysis was to evaluate the impact of ankylosing spondylitis on the health-related quality of life assessed by the Medical Outcomes Short-Form-36 questionnaire (SF-36).

METHODS

A systematic literature search was performed on PubMed and Web of Science until January 22, 2016 to obtain eligible studies. Random effect model was performed to summarize the scores of each domain. The radar chart was used to compare the scores of AS patients with other health conditions. Spearman's correlation analysis and meta-regression were used to explore the related factors. STATA (version 11.0) and SPSS (version 13.0) were adopted in this meta-analysis.

RESULTS

Thirty-eight studies were included in this study, which were all reliable to summarize the scores of the SF-36. Pooled mean scores of the physical health domains ranged from 45.93 to 58.17, with the RP and PF domains being the lowest and the highest, respectively. Pooled mean scores of the mental health domains ranged from 47.49 to 62.52, with the VT and SF domains being the lowest and the highest, respectively. Besides, the physical component summary was lower than the mental component summary. BASDAI and BASFI were negatively associated with some domains of the SF-36 significantly. Patients with AS had a substantial impaired HRQoL in comparison with the general population.

CONCLUSIONS

AS could adversely affect the HRQoL of patients. Measuring HRQoL should be considered as an essential part of the overall assessment of health status of AS patients, which would provide valuable clues for improving the management of disease and making decisions regarding treatment.

The impact of ankylosing spondylitis/axial spondyloarthritis on work productivity

Ankylosing spondylitis (AS) is a chronic inflammatory condition that has a significant impact on the quality of life and work productivity. New classification criteria have enabled earlier diagnosis of this condition. However, work productivity is an important issue that is still often overlooked during clinical assessments and consultations. This article focusses on the relationship between axial spondyloarthritis (axial SpA) and work productivity. It summarises the impact of this condition on work productivity, and it highlights the tools available to assess this. It also highlights the increasing role and potential of employers, health professionals and new treatments for enhancing work productivity for people with this condition.

Improvements in productivity at paid work and within the household, and increased participation in daily activities after 24 weeks of certolizumab pegol treatment of patients with psoriatic arthritis: results of a phase 3 double-blind randomised placebo-controlled study

OBJECTIVES

To evaluate the effect of certolizumab pegol (CZP) on productivity outside and within the home, and on participation in family, social and leisure activities in adult patients with psoriatic arthritis (PsA).

METHODS

RAPID-PsA (NCT01087788) is a phase 3, double-blind, placebo-controlled trial. 409 patients with active PsA were randomised 1:1:1 to placebo, CZP 200 mg every 2 weeks (Q2W) or CZP 400 mg every 4 weeks (Q4W). The arthritis-specific Work Productivity Survey (WPS) assessed the impact of PsA on paid work and household productivity, and participation in social activities during the preceding month. WPS responses were compared between treatment arms using a non-parametric bootstrap-t method.

RESULTS

At baseline, 56.6%, 60.1% and 61.5% of placebo, CZP 200 mg Q2W and CZP 400 mg Q4W patients were employed. By week 24, employed CZP patients reported an average of 1.0-1.8 and 3.0-3.9 fewer days of absenteeism and presenteeism, respectively, per month compared with 1.0 and 0.3 fewer days for placebo patients (p<0.05). Within the home, by week 24, CZP patients reported an average of 3.0-3.5 household work days gained per month versus 1.0 day for placebo (p<0.05). CZP patients also reported fewer days with reduced household productivity or days lost for participation in family, social and leisure activities. Improvements with CZP were seen as early as week 4 and continued to week 24.

CONCLUSIONS

CZP treatment significantly improved productivity at paid work and within the home, and resulted in greater participation in social activities for PsA patients.

TRIAL REGISTRATION NUMBER

NCT01087788.

Discriminant validity, responsiveness and reliability of the arthritis-specific Work Productivity Survey assessing workplace and household productivity within and outside the home in patients with axial spondyloarthritis, including nonradiographic axial spondyloarthritis and ankylosing spondylitis

INTRODUCTION

The arthritis-specific Work Productivity Survey (WPS) was developed to evaluate productivity limitations associated with arthritis within and outside the home. There is an unmet need for an instrument assessing similar productivity limitations in axial spondyloarthritis (axSpA), including nonradiographic axSpA and ankylosing spondylitis. Following its validation in rheumatoid and psoriatic arthritis, we aimed to assess psychometric properties of WPS in adult-onset active axSpA in this analysis.

METHODS

Psychometric properties were assessed using data from the RAPID-axSpA trial (NCT01087762) in which researchers investigated certolizumab pegol efficacy and safety in axSpA. WPS was completed at baseline and every 4 weeks until week 24. Validity was evaluated at study baseline via known-groups defined by the first and third quartile cutoffs of patient scores to Ankylosing Spondylitis Disease Activity Score (ASDAS), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), back pain, Bath Ankylosing Spondylitis Functional Index (BASFI), Short Form 36 health survey (SF-36) and Ankylosing Spondylitis Quality of Life Scale (ASQoL). Responsiveness and reliability were assessed by comparing WPS mean changes in ASAS 20% improvement criteria (ASAS20), BASDAI50, ASDAS clinically important improvement/major improvement (CII/MI) and BASFI minimum clinically important difference (MCID) responders versus nonresponders at week 12. All comparisons were conducted on observed cases in the randomized set using a nonparametric bootstrap-t method.

RESULTS

The results confirmed the psychometric properties of WPS. AxSpA patients with a worse health state had significantly more days of household work lost, household work with reduced productivity, social activities missed and outside help hired, as well as a higher interference rate of arthritis, than patients with a better health state. Similarly, employed patients with a worse health state had significantly more work days lost or with productivity reduced, and a higher interference of arthritis on work productivity. Similar findings were also observed in the nonradiographic (nr) axSpA and AS subpopulations. The WPS was responsive to clinical changes, with responders reporting larger improvements at week 12 in WPS scores versus nonresponders. Effect sizes in responders were generally moderate to large (standardized response mean >0.5).

CONCLUSIONS

These analyses demonstrate that WPS is a valid, responsive and reliable instrument for the measurement of productivity within and outside the home in adult-onset axSpA, as well as the in subpopulations of AS and nr-axSpA.