Construct validity of Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) treatment target cut-offs in a BASDAI treat-to-target axial spondyloarthritis cohort: a cross-sectional study.

OBJECTIVE: In axial spondyloarthritis (axSpA), the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) are recommended for use in treat-to-target (T2T) strategies. However, BASDAI disease states may be a less suitable T2T instrument than ASDAS, since BASDAI contains non-disease activity related items. The objective of our study was to investigate the construct validity of BASDAI and ASDAS disease states. METHOD: We performed a single-centre cross-sectional study on BASDAI and ASDAS construct validity in long-term BASDAI T2T-treated axSpA patients. Our hypothesis was that BASDAI is less representative of disease activity than ASDAS owing to the focus on pain and fatigue, and missing an objective item, e.g. C-reactive protein (CRP). This was operationalized using several subhypotheses. RESULTS: The study included 242 axSpA patients. BASDAI and ASDAS disease states showed a similar relation to Patient Acceptable Symptom State and T2T protocol adherence. The proportions of patients with high BASDAI and ASDAS disease activity fulfilling Central Sensitization Inventory and fibromyalgia syndrome criteria were similar. The correlation with fatigue was moderate for both BASDAI (Spearman's rho 0.64) and ASDAS (Spearman's rho 0.54) disease states. A high ASDAS was strongly correlated with increased CRP (relative risk 6.02, 95% CI 3.0-12.09), while this correlation was not seen for BASDAI (relative risk 1.13, 95% CI 0.74-1.74). CONCLUSION: Our study showed moderate and comparable construct validity for BASDAI- and ASDAS-based disease activity states, with the expected exception of association with CRP. Therefore, no strong preference can be given for either measure, although the ASDAS seems marginally more valid.

Cost-effectiveness of five different anti-tumour necrosis factor tapering strategies in rheumatoid arthritis: a modelling study.

Objective: To investigate the cost-effectiveness of five different tumour necrosis factor inhibitor tapering strategies in patients with rheumatoid arthritis (RA) and stable low disease activity, using a modelling design.Method: Using Markov models based on data from the DRESS and STRASS randomized controlled trials, and the Nijmegen RA cohort, five tapering strategies for etanercept and adalimumab were tested against continuation: 1, four-step tapering (DRESS strategy); 2, five-step tapering; 3, tapering without withdrawal; 4, use of a stricter flare criterion; and 5, use of a theoretical predictor for successful tapering. We also examined how well a biomarker should be able to predict in order for strategy 5 to become cost-effective compared to the other strategies.Results: All examined tapering strategies were cost saving (range: EUR 5128 to 7873) but yielded more short-lived flares compared to continuation. The change in utilities compared to continuation was minimal and not clinically relevant (range: -0.005 to 0.007 quality-adjusted life-years). Strategy 1 was cost-effective compared to all other strategies [highest incremental net monetary benefit (iNMB)]. However, there was a large overlap in credible intervals, especially between strategies 1 and 2. Scenario analyses showed that 50% reduction of drug prices would result in the highest iNMB for strategy 2. A biomarker only becomes cost-effective when it is inexpensive and has a sensitivity and specificity of at least 84%.Conclusion: Because our study showed a comparable iNMB for tapering in four or five steps (including discontinuation), we recommend a choice between these strategies, based on shared decision making.

Implementation of protocolized tight control and biological dose optimization in daily clinical practice: results of a pilot study.

OBJECTIVES: To assess the effects of education, guideline development, and individualized treatment advice on rheumatologist adherence to tight control-based treatment and biological dose optimization in rheumatoid arthritis (RA), psoriatic arthritis (PsA), and spondyloarthropathy (SpA) patients. METHOD: This pilot study, among two rheumatologists and two specialized nurses in a general hospital, combined education, feedback, local guideline development, and individualized treatment advice. Outcomes (baseline and 1 year post-intervention) were the percentage of patients with a Disease Activity Score in 28 joints (DAS28) or Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) measured during the visit, mean DAS28/BASDAI, and the percentage of patients using a reduced biological dose. DAS28 outcomes only applied to RA and PsA patients, BASDAI outcomes only applied to SpA patients whereas outcomes on biological dose applied to all patients. RESULTS: A total of 232 patients (67% RA, 15% PsA, 18% SpA; 58% female, mean age 56 ± 15 years) were included in the study. The percentage of DAS28 and BASDAI measurements performed increased after the intervention [DAS28 15-51%, odds ratio (OR) 3.3, 95% confidence interval (CI) 2.1-5.5; BASDAI 23-50%, OR 2.2, 95% CI 1.0-5.5], with mean DAS28 and BASDAI scores remaining similar (DAS28: mean difference 0.1, 95% CI -0.3 to 0.5; BASDAI: mean difference 0.03, 95% CI -1.8 to 1.9). Use of a reduced biological dose increased from 10% to 61% (OR 3.9, 95% CI 2.4-6.5). CONCLUSIONS: A multicomponent intervention strategy aimed at rheumatologists can lead to improved adherence to tight control-based treatment and a reduction in the use of biologicals in RA, SpA, and PsA patients.

Responsiveness of four patient-reported outcome measures to assess physical function in patients with knee osteoarthritis.

OBJECTIVES: The aim of this study was to evaluate the responsiveness of four patient-reported outcome measures (PROMs) to measure change in physical function simultaneously in patients with knee osteoarthritis (OA) following currently recommended COSMIN (COnsensus-based Standards for the selection of health status Measurement INstruments) standards. METHOD: Patients with knee OA receiving conservative treatment following a stepped care approach were invited to complete a set of questionnaires at baseline and 3 months. Questionnaires included four widely used measures of physical function: the Knee Injury and Osteoarthritis Outcome Score Physical Function Short Form (KOOS-PS), the Lequesne algofunctional index (LAI), the Lower Extremity Functional Scale (LEFS), and the Western Ontario and McMaster University Osteoarthritis Index Physical Function subscale (WOMAC-PF). Responsiveness of physical function was investigated according to the COSMIN standards by testing 15 a priori defined hypotheses. Responsiveness was considered positive if > 75% of the hypotheses could be confirmed. RESULTS: A total of 161 patients participated [61% female, mean (sd) age 59 (9) years and body mass index 29.7 (5.0) kg/m2]. Baseline values of the four PROMs were, mean (sd): KOOS-PS 53.6 (16.8), LAI 11.0 (4.0), LEFS 40.6 (14.1), and WOMAC-PF 51.8 (19.4). We could confirm 12 out of 15 predefined hypotheses (80%) about expected correlations for the WOMAC-PF whereas for the KOOS-PS, LAI, and LEFS < 75% hypotheses could be confirmed (73, 67, and 73%. respectively). CONCLUSIONS: Our results suggest that the WOMAC-PF is able to detect changes over time in physical function and therefore should be the measure of first choice in clinical trials evaluating the effectiveness of an intervention on physical function in knee OA patients.

Prediction of successful dose reduction or discontinuation of adalimumab, etanercept, or infliximab in rheumatoid arthritis patients using serum drug levels and antidrug antibody measurement.

BACKGROUND: To evaluate if TNF inhibitor serum drug levels (DL) or anti-drug antibodies (ADAb) can predict successful dose reduction (in patients with high DL) or discontinuation (in patients with no/low DL or ADAb) in rheumatoid arthritis (RA) patients. RESEARCH DESIGN AND METHODS: RA patients that were using adalimumab (n = 42), etanercept (n = 76) or infliximab (n = 51) and were doing well, were tapered until discontinuation or flare (1-1.5 year follow up). Random timed DL for adalimumab and etanercept and trough DL for infliximab were measured before dose reduction: Receiver-Operator-Curves (ROC) analyses with optimal cut-off DL were determined. RESULTS: No predictive value of adalimumab and infliximab DL for all outcomes were found, except for an inverse association of lower etanercept DL and higher chance for successful dose reduction (Area Under the Curve (AUC) 0.36, 95% CI 0.23-0.49; cut-off <2.6 mg/l). In sub analyses, higher adalimumab trough DL predicted successful dose reduction (AUC 0.86, 0.58-1.00; cut-off >7.8). ADAb were infrequent and not predictive of successful discontinuation. CONCLUSIONS: No predictive value of baseline adalimumab, etanercept and infliximab DL or ADAb for successful dose reduction or discontinuation in RA was found in this context, with the possible exception of high adalimumab trough levels for successful dose reduction.