Assessing the effect of interventions for axial spondyloarthritis according to the endorsed ASAS/OMERACT core outcome set: a meta-research study of trials included in Cochrane reviews.

The Assessment of SpondyloArthritis international Society (ASAS) has defined core sets for (i) symptom-modifying anti-rheumatic drugs (SM-ARD), (ii) clinical record keeping, and (iii) disease-controlling anti-rheumatic therapy (DC-ART). These include the following domains for all three core sets: "physical function," "pain," "spinal mobility," "spinal stiffness," and "patient's global assessment" (PGA). The core set for clinical record keeping further includes the domains "peripheral joints/entheses" and "acute phase reactants," and the core set for DC-ART further includes the domains "fatigue" and "spine radiographs/hip radiographs." The Outcome Measures in Rheumatology (OMERACT) endorsed the core sets in 1998.Using empirical evidence from axSpA trials, we investigated the efficacy (i.e., net benefit) according to the ASAS/OMERACT core outcome set for axSpA across all interventions tested in trials included in subsequent Cochrane reviews. For all continuous scales, we combined data using the standardized mean difference (SMD) to meta-analyze outcomes involving the same domains. Also, through meta-regression analysis, we examined the effect of the separate SMD measures (independent variables) on the primary endpoint (log [OR], dependent variable) across all trials.Based on 11 eligible Cochrane reviews, from these, 85 articles were screened; we included 43 trials with 63 randomized comparisons. Mean (SD) number of ASAS/OMERACT core outcome domains measured for SM-ARD/physical therapy trials was 4.2 (1.7). Six trials assessed all proposed domains. Mean (SD) for number of core outcome domains for DC-ART trials was 5.8 (1.7). No trials assessed all nine domains. Eight trials (16%) were judged to have inadequate (i.e., high risk of) selective outcome reporting bias. The most responsible core domains for achieving success in meeting the primary objective per trial were pain, OR (95% CI) 5.19 (2.28, 11.77), and PGA, OR (95% CI) 1.87 (1.14, 3.07). In conclusion, selective outcome reporting (and "missing data") should be reduced by encouraging the use of the endorsed ASAS/OMERACT outcome domains in clinical trials. Overall outcome reporting was good for SM-ARD/physical therapy trials and poor for DC-ART trials. Our findings suggest that both PGA and pain provide a valuable holistic construct for the assessment of improvement beyond more objective measures of spinal inflammation.

The impact of sex and disease classification on patient-reported outcome measures in axial spondyloarthritis: a descriptive prospective cross-sectional study.

BACKGROUND: The aim of this study was to explore the impact of sex and disease classification on outcomes in axial spondyloarthritis (axSpA) patients, including both radiographic (r-) axSpA and non-radiographic (nr-) axSpA, in males and females, respectively. METHODS: AxSpA patients were consecutively recruited from two rheumatology outpatient university clinics. We explored how sex and axSpA disease classification affected patient-reported outcome measures (PROMs). General linear models were used to investigate if there was an association between the continuous variables and each of the main effects of interest (sex and axSpA classification), as well as the possible interaction between them. Categorical outcome measures were analyzed with the use of logistic regression with the same fixed effects. We analyzed the relationship between tender point count (TPC) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). The prevalence of extra-articular manifestations (EAMs) and the Charlson Comorbidity Index (CCI) were determined. RESULTS: According to the protocol, a total of 100 outpatients with axSpA were enrolled (r-axSpA males 30, r-axSpA females 10, nr-axSpA males 25, nr-axSpA females 35). The BASDAI scores appeared higher among nr-axSpA females (median [Q1; Q3], 47 [21; 60]) compared with the combined median for the 3 other subgroups 25 [12; 25]. Female sex was associated with a higher number of tender point count (TPC, P < 0.001). TPC and BASDAI were correlated for female nr-axSpA patients (r = 0.44, P = 0.008) and male nr-axSpA patients (r = 0.56, P = 0.003). Being classified as nr-axSpA was associated with a lower SF-36 Mental Component Summary (median for the 4 subgroups: nr-axSpa females 46.7, nr-axSpA males 52.3 vs. r-axSpA males 56.9 and r-axSpA females 50.4). EAMs were frequent (up to 50%). The CCI was low in all 4 subgroups, and no difference in the CCI between the subgroups was observed (P = 0.14). However, male sex had a significant impact on the CCI (P = 0.03). CONCLUSIONS: In summary, patients with r-axSpA, regardless of sex, appeared less affected on most PROMs compared with nr-axSpA patients. However, female sex was associated with a higher number of TPC. TPC could possibly confound disease activity outcomes such as BASDAI, and one can consider different thresholds for defining high disease activity depending on the patient's sex. TRIAL REGISTRATION: The trial is registered and approved by the Region of Southern Denmark's Ethics Committee ( S-20150219 ). Registered 19 February 2015.

No further gain can be achieved by calculating Disease Activity Score in 28 joints with high-sensitivity assay of C-reactive protein because of high intraindividual variability of C-reactive protein: A cross-sectional study and theoretical consideration.

Disease Activity Score in 28 joints (DAS28) is commonly used to evaluate disease activity of rheumatoid arthritis (RA) and is a guide to treatment decision.The aim of this study was to evaluate the impact of lower reporting limit for C-reactive protein (CRP), with respect to intraindividual biological variability, on the calculation of DAS28 and subsequent patient classification.This study consists of 2 sections: a theoretical consideration discussing the performance of CRP in calculating DAS28 taking intraindividual biological variation and lower reporting limit for CRP into account and a cross-sectional study of RA patients applying our theoretical results. Therefore, we calculated DAS28 twice, with the actual CRP values and CRP = 9 mg/L, the latter to elucidate the positive effects of reducing the lower reporting limit of CRP from <10 to <3 mg/L.Lower-reporting limit of <10 mg/L leads to overestimate DAS28. However, reducing lower reporting limit for CRP to <3 mg/L results in optimizing DAS28 calculation. Further lowering of reporting limit for CRP to <3 mg/L does not increase the precision of DAS28 owing to the relatively large intraindividual biological variation.Five hundred twelve patients were included. There was a significant difference between recalculated and patients DAS28 (P < 0.001). One hundred nine patients had DAS28 deviation (compatible to remission to low: 66, low to moderate: 39. and moderate to high: 4).Owing to significant impact of intraindividual biologic variation on DAS28 and patient classification, special attention should be paid to calculate DAS28 when CRP values are within normal range. Furthermore, we conclude that results of different studies evaluating DAS28 and treatment response are not comparable if the reporting limits of CRP are unknown.