Measurement error in the assessment of radiographic progression in rheumatoid arthritis (RA) clinical trials: the smallest detectable change (SDC) revisited

Effect of Secukinumab Versus Adalimumab Biosimilar on Radiographic Progression in Patients With Radiographic Axial Spondyloarthritis: Results From a Head-to-Head Randomized Phase IIIb Study

OBJECTIVE

Spinal radiographic progression is an important outcome in radiographic axial spondyloarthritis (SpA). The objective of the phase IIIb SURPASS study was to compare spinal radiographic progression in patients with radiographic axial SpA treated with secukinumab (interleukin-17A inhibitor) versus adalimumab biosimilar (Sandoz adalimumab [SDZ-ADL]; tumor necrosis factor inhibitor).

METHODS

Biologic-naive patients with active radiographic axial SpA, at high risk of radiographic progression (high-sensitivity C-reactive protein [hsCRP] ≥5 mg/L and/or ≥1 syndesmophyte[s] on spinal radiographs), were randomized (1:1:1) to secukinumab (150/300 mg) or SDZ-ADL (40 mg). The proportion of patients with no radiographic progression (change from baseline [CFB] in modified Stoke Ankylosing Spondylitis Spinal Score [mSASSS] ≤0.5) on secukinumab versus SDZ-ADL at week 104 (primary endpoint), mean CFB-mSASSS, proportion of patients with ≥1 syndesmophyte(s) at baseline with no new syndesmophyte(s), and safety were evaluated.

RESULTS

Overall, 859 patients (78.5% male, mSASSS 16.6, Bath Ankylosing Spondylitis Disease Activity Index 7.1, hsCRP 20.4 mg/L, and 73.0% with ≥1 syndesmophyte[s]) received secukinumab 150 mg (n = 287), secukinumab 300 mg (n = 286), or SDZ-ADL (n = 286). At week 104, the proportion of patients with no radiographic progression was 66.1%, 66.9%, and 65.6% (P = not significant, both secukinumab doses) and mean CFB-mSASSS was 0.54, 0.55, and 0.72 in secukinumab 150 mg, secukinumab 300 mg, and SDZ-ADL arms, respectively. Overall, 56.9%, 53.8%, and 53.3% of patients on secukinumab 150 mg, secukinumab 300 mg, and SDZ-ADL, respectively, with ≥1 syndesmophyte(s) at baseline did not develop new syndesmophyte(s) by week 104. There were no unexpected safety findings.

CONCLUSION

Spinal radiographic progression over two years was low with no significant difference between secukinumab and SDZ-ADL arms. The safety of both treatments was consistent with previous reports.

Two-year imaging outcomes from a phase 3 randomized trial of secukinumab in patients with non-radiographic axial spondyloarthritis

BACKGROUND

Radiographic progression and course of inflammation over 2 years in patients with non-radiographic axial spondyloarthritis (nr-axSpA) from the phase 3, randomized, PREVENT study are reported here.

METHODS

In the PREVENT study, adult patients fulfilling the Assessment of SpondyloArthritis International Society classification criteria for nr-axSpA with elevated CRP and/or MRI inflammation received secukinumab 150 mg or placebo. All patients received open-label secukinumab from week 52 onward. Sacroiliac (SI) joint and spinal radiographs were scored using the modified New York (mNY) grading (total sacroiliitis score; range, 0-8) and modified Stoke Ankylosing Spondylitis Spine Score (mSASSS; range, 0-72), respectively. SI joint bone marrow edema (BME) was assessed using the Berlin Active Inflammatory Lesions Scoring (0-24) and spinal MRI using the Berlin modification of the AS spine MRI (ASspiMRI) scoring (0-69).

RESULTS

Overall, 78.9% (438/555) of patients completed week 104 of the study. Over 2 years, minimal changes were observed in total radiographic SI joint scores (mean [SD] change, - 0.04 [0.49] and 0.04 [0.36]) and mSASSS scores (0.04 [0.47] and 0.07 [0.36]) in the secukinumab and placebo-secukinumab groups. Most of the patients showed no structural progression (increase ≤ smallest detectable change) in SI joint score (87.7% and 85.6%) and mSASSS score (97.5% and 97.1%) in the secukinumab and placebo-secukinumab groups. Only 3.3% (n = 7) and 2.9% (n = 3) of patients in the secukinumab and placebo-secukinumab groups, respectively, who were mNY-negative at baseline were scored as mNY-positive at week 104. Overall, 1.7% and 3.4% of patients with no syndesmophytes at baseline in the secukinumab and placebo-secukinumab group, respectively, developed ≥ 1 new syndesmophyte over 2 years. Reduction in SI joint BME observed at week 16 with secukinumab (mean [SD], - 1.23 [2.81] vs - 0.37 [1.90] with placebo) was sustained through week 104 (- 1.73 [3.49]). Spinal inflammation on MRI was low at baseline (mean score, 0.82 and 1.07 in the secukinumab and placebo groups, respectively) and remained low (mean score, 0.56 at week 104).

CONCLUSION

Structural damage was low at baseline and most patients showed no radiographic progression in SI joints and spine over 2 years in the secukinumab and placebo-secukinumab groups. Secukinumab reduced SI joint inflammation, which was sustained over 2 years.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02696031.

Test-retest reliability of outcome measures: data from three trials in radiographic and non-radiographic axial spondyloarthritis

Objectives

Aim of this study was to assess test–retest reliability of candidate instruments for the mandatory domains of the Assessment of Spondyloarthritis international Society (ASAS)-Outcome Measures in Rheumatology core set for axial spondyloarthritis (axSpA).

Methods

Screening and baseline data from COAST-V, COAST-X and RAPID-axSpA was used to evaluate test–retest reliability of each candidate instrument for the mandatory domains (disease activity, pain, morning stiffness, fatigue, physical function, overall functioning and health). A maximum time interval of 28 days between both visits was used for inclusion in this study. Test–retest reliability was assessed by intraclass correlation coefficient (ICC). Bland and Altman plots provided mean difference and 95% limits of agreement, which were used to calculate the smallest detectable change (SDC). Data were analysed for radiographic and non-radiographic axSpA separately.

Results

Good reliability was found for Ankylosing Spondylitis Disease Activity Score (ICC 0.79, SDC 0.6), C reactive protein (ICC 0.72–0.79, SDC 12.3–17.0), Bath Ankylosing Spondylitis Functional Index (ICC 0.87, SDC 1.1) and 36-item Short-Form Health Survey (ICC Physical Component Summary 0.81, SDC 4.7, Mental Component Summary 0.80, SDC 7.3). Moderate reliability was found for Bath Ankylosing Spondylitis Disease Activity Index (ICC 0.72, SDC 1.1), patient global assessment (ICC 0.58, SDC 1.5), total back pain (ICC 0.64, SDC 1.3), back pain at night (ICC 0.67, SDC 1.3), morning stiffness (ICC 0.52–0.63, SDC 1.5–2.2), fatigue (ICC 0.65, SDC 1.3) and ASAS-Health Index (ICC 0.74, SDC 2.5). Reliability and SDC for the radiographic and non-radiographic axSpA subgroups were similar.

Conclusion

Overall reliability was good, and comparable levels of reliability were found for patients with radiographic and non-radiographic axSpA, even though most instruments were developed for radiographic axSpA. Composite measures showed higher reliability than single-item measures in assessing disease activity in patients with axSpA.

Bone changes in early inflammatory arthritis assessed with High-Resolution peripheral Quantitative Computed Tomography (HR-pQCT): A 12-month cohort study

OBJECTIVES

Erosion development is of crucial significance as it impacts prognosis and therapy decisions in patients with inflammatory joint diseases. Our study aimed to determine the sensitivity of high-resolution peripheral quantitative computed tomography (HR-pQCT) to detect change of bone surface over time and to identify erosion development in early inflammatory arthritis (EIA) patients. Moreover, the contribution of prognostic factors on periarticular bone damage in the first year of diagnosis assessed by HR-pQCT was explored.

METHODS

46 patients with arthritic symptoms for less than one year, and a clinical diagnosis of inflammatory arthritis were prospectively imaged at baseline and 12-months. HR-pQCT scans of the 2nd and 3rd MCP joints and CR of the hands and feet were performed. Joint space width (JSW), total bone mineral density (Tt.BMD), erosion presence and volume were assessed with HR-pQCT. Scan-rescan precision was assessed to define an individual-level least significant change (LSC) criterion. Regression analyses explored prognostic factors for bone damage progression.

RESULTS

We observed no significant group-level changes in JSW, Tt.BMD or erosion volume. 20% or fewer joints demonstrated individual-level changes greater than the LSC criterion for mean JSW, Tt.BMD and erosion volume. HR-pQCT detected more erosions than CR in the 2nd and 3rd MCP. Increased symptom duration at diagnosis was weakly associated (P<0.10) with lower JSW minimum and higher JSW standard deviation.

CONCLUSIONS

Gradual degradation of JSW, proportional to symptom duration, was detected by HR-pQCT. EIA patients need to be closely monitored for exacerbation of arthritis and progression of periarticular bone damage.

Disease activity measures at baseline predict structural damage progression: data from the randomized, controlled AMPLE and AVERT trials

Objective

Data from two double-blind, randomized, Phase III studies were analysed to investigate the ability of Routine Assessment of Patient Index Data 3, DAS28 (CRP), modified (M)-DAS28 (CRP) and Simplified or Clinical Disease Activity Indices to predict structural damage progression in RA.

Methods

This post hoc analysis included data from the 2-year Abatacept vs adaliMumab comParison in bioLogic-naïvE RA subjects with background MTX (AMPLE) trial in biologic-naïve patients with active RA (<5 years) and an inadequate response to MTX, and the 12-month treatment period of the Assessing Very Early Rheumatoid arthritis Treatment (AVERT) trial in MTX-naïve patients with early RA (⩽2 years) and poor prognostic indicators. Adjusted logistic regression analysis assessed the relationship between baseline disease activity and structural damage progression (defined as change from baseline greater than the smallest detectable change) at 12 and 24 months in AMPLE and 6 and 12 months in AVERT. Areas under the receiver operating characteristic curves for the impact of baseline disease activity on structural damage progression were calculated.

Results

Adjusted logistic regression analyses included all randomized and treated patients in AMPLE (N = 646) and those who received abatacept plus MTX or MTX monotherapy in AVERT (N = 235). Baseline Routine Assessment of Patient Index Data 3, DAS28 (CRP) and M-DAS28 (CRP) scores significantly predicted structural progression at months 12 and 24 in AMPLE (P < 0.05) and months 6 and 12 in AVERT (P < 0.01), and were stronger predictors than Simplified or Clinical Disease Activity Indices.

Conclusion

In this post hoc analysis of two patient populations with RA, Routine Assessment of Patient Index Data 3, DAS28 (CRP) and M-DAS28 (CRP) were good at predicting structural damage.

Trial registration

ClinicalTrials.gov, http://clinicaltrials.gov: NCT00929864 (AMPLE); NCT01142726 (AVERT).

Synovial fluid monocyte/macrophage subsets and their correlation to patient-reported outcomes in osteoarthritic patients: a cohort study

BACKGROUND

Chronic, low-grade inflammation of the synovium (synovitis) is a hallmark of osteoarthritis (OA), thus understanding of OA immunobiology, mediated by immune effectors, is of importance. Specifically, monocytes/macrophages (MΦs) are known to be abundantly present in OA joints and involved in OA progression. However, different subsets of OA MΦs have not been investigated in detail, especially in terms of their relationship with patient-reported outcome measures (PROMs). We hypothesized that levels of synovial fluid (SF) MΦ subsets are indicative of joint function and quality of life in patients with OA, and can therefore serve as biomarkers and therapeutic targets for OA.

METHODS

In this cohort study, synovial fluid leukocytes (SFLs, N = 86) and peripheral blood mononuclear cells (n = 53) from patients with knee OA were characterized. Soluble MΦ receptors and chemokine (sCD14, sCD163, CCL2, CX3CL1) levels were detected in SF using immunoassays. Linear models, adjusted for sex, age and body mass index, were used to determine associations between SF MΦs and soluble factors with PROMs (N = 83). Pearson correlation was calculated to determine correlation between MΦ subsets, T cells and soluble factors.

RESULTS

SF MΦs were the most abundant SFLs. Within these, the double-positive CD14+CD16+-MΦ subset is enriched in knee OA SF compared to the circulation. Importantly, MΦ subset ratios correlated with PROMs, specially stiffness, function and quality of life. Interestingly, the SF CD14+CD16+-MΦ subset ratio correlated with SF chemokine (C-C motif) ligand 2 (CCL2) levels but not with levels of sCD163 or sCD14; we found no association between PROMs and either SF CCL2, sCD163, sCD14 or CX3CL1 (which was below detection levels). All SF MΦs displayed high levels of HLA-DR, suggesting an activated phenotype. Correlation between OA SF MΦ subsets and activated CD4+ T cell subsets suggests modulation of CD4+ T cell activation by MΦs.

CONCLUSION

SF MΦ subsets are associated with knee OA PROMs and display an activated phenotype, which may lead to modulation of CD4+ T cell activation. Knee OA SF MΦ subsets could serve as knee OA function biomarkers and as targets of novel therapeutics.

Long-term outcomes after disease activity-guided dose reduction of TNF inhibition in rheumatoid arthritis: 3-year data of the DRESS study - a randomised controlled pragmatic non-inferiority strategy trial

OBJECTIVE

Tumour necrosis factor inhibitors (TNFi) are effective in rheumatoid arthritis (RA), but disadvantages include adverse events (AEs) and high costs. This can be improved by disease activity-guided dose reduction (DR). We aimed to assess long-term outcomes of TNFi DR in RA by using 3-year data from the DRESS study (Dose REduction Strategy of Subcutaneous TNF inhibitors study).

METHODS

In the intervention phase (month 0-18) of the DRESS study (Dutch trial register, NTR 3216), patients were randomised to DR or usual care (UC). In the extension phase (month 18-36), treatment strategies in both groups converged to continuation of protocolised tight control and allowed dose optimisation. Intention-to-treat analyses were done on flare, disease activity (28 joint count-based disease activity score with C reactive protein (DAS28-CRP)), functioning (health assessment questionnaire-disability index (HAQ-DI)), quality of life (Euroqol 5 dimensions 5 levels questionnaire (EQ5D-5L)), medication use, radiographic progression (Sharp van der Heijde score (SvdH)) and AE.

RESULTS

172/180 patients included in the DRESS study were included in the extension phase. Cumulative incidences of major flare were 10% and 12% (-2%, 95% CI -8 to 15) in DR and UC groups in the extension phase, and 17% and 14% (3%, 95% CI -9 to 13) from 0 to 36 months. Cumulative incidences of short-lived flares were 43% (33 to 52%)%) and 35% (23 to 49%)%) in DR and UC groups in the extension phase, and 83% (75 to 90%)%) and 44% (31 to 58%)%) from 0 to 36 months. Mean DAS28-CRP, HAQ-DI, EQ5D-5L and SvdH remained stable and not significantly different between groups. TNFi use remained low in the DR group and decreased in the UC group. Cumulative incidences of AE were not significantly different between groups.

CONCLUSIONS

Safety and efficacy of disease activity guided TNFi DR in RA are maintained up to 3 years, with a large reduction in TNFi use, but no other benefits. Implementation of DR would vastly improve the cost-effective use of TNFi.

Predictive factors of radiological progression after 2 years of remission-steered treatment in early arthritis patients: a post hoc analysis of the IMPROVED study

OBJECTIVES

To identify predictive factors of radiological progression in early arthritis patients treated by remission-steered treatment.

METHODS

In the IMPROVED study, 610 patients with early rheumatoid arthritis (RA) or undifferentiated arthritis (UA) were treated with methotrexate (MTX) and a tapered high dose of prednisone. Patients in early remission (disease activity score (DAS) <1.6 after 4 months) tapered prednisone to zero. Patients not in early remission were randomised to arm 1: MTX plus hydroxychloroquine, sulfasalazine and prednisone, or to arm 2: MTX plus adalimumab. Predictors of radiological progression (≥0.5 Sharp/van der Heijde score; SHS) after 2 years were assessed using logistic regression analysis.

RESULTS

Median (IQR) SHS progression in 488 patients was 0 (0-0) point, without differences between RA or UA patients or between treatment arms. In only 50/488 patients, the SHS progression was ≥0.5: 33 (66%) were in the early DAS remission group, 9 (18%) in arm 1, 5 (10%) in arm 2, 3 (6%) in the outside of protocol group. Age (OR (95% CI): 1.03 (1.00 to 1.06)) and the combined presence of anticarbamylated protein antibodies (anti-CarP) and anticitrullinated protein antibodies (ACPA) (2.54 (1.16 to 5.58)) were independent predictors for SHS progression. Symptom duration <12 weeks showed a trend.

CONCLUSIONS

After 2 years of remission steered treatment in early arthritis patients, there was limited SHS progression in only a small group of patients. Numerically, patients who had achieved early DAS remission had more SHS progression than other patients. Positivity for both anti-CarP and ACPA and age were independently associated with SHS progression.

TRIAL REGISTRATION NUMBERS

ISRCTN Register number 11916566 and EudraCT number 2006 06186-16.

Disease activity guided dose reduction and withdrawal of adalimumab or etanercept compared with usual care in rheumatoid arthritis: open label, randomised controlled, non-inferiority trial

OBJECTIVE

To evaluate whether a disease activity guided strategy of dose reduction of two tumour necrosis factor (TNF) inhibitors, adalimumab or etanercept, is non-inferior in maintaining disease control in patients with rheumatoid arthritis compared with usual care.

DESIGN

Randomised controlled, open label, non-inferiority strategy trial.

SETTING

Two rheumatology outpatient clinics in the Netherlands, from December 2011 to May 2014.

PARTICIPANTS

180 patients with rheumatoid arthritis and low disease activity using adalimumab or etanercept; 121 allocated to the dose reduction strategy, 59 to usual care.

INTERVENTIONS

Disease activity guided dose reduction (advice to stepwise increase the injection interval every three months, until flare of disease activity or discontinuation) or usual care (no dose reduction advice). Flare was defined as increase in DAS28-CRP (a composite score measuring disease activity) greater than 1.2, or increase greater than 0.6 and current score of at least 3.2. In the case of flare, TNF inhibitor use was restarted or escalated.

MAIN OUTCOME MEASURES

Difference in proportions of patients with major flare (DAS28-CRP based flare longer than three months) between the two groups at 18 months, compared against a non-inferiority margin of 20%. Secondary outcomes included TNF inhibitor use at study end, functioning, quality of life, radiographic progression, and adverse events.

RESULTS

Dose reduction of adalimumab or etanercept was non-inferior to usual care (proportion of patients with major flare at 18 months, 12% v 10%; difference 2%, 95% confidence interval -12% to 12%). In the dose reduction group, TNF inhibitor use could successfully be stopped in 20% (95% confidence interval 13% to 28%), the injection interval successfully increased in 43% (34% to 53%), but no dose reduction was possible in 37% (28% to 46%). Functional status, quality of life, relevant radiographic progression, and adverse events did not differ between the groups, although short lived flares (73% v 27%) and minimal radiographic progression (32% v 15%) were more frequent in dose reduction than usual care.

CONCLUSIONS

A disease activity guided, dose reduction strategy of adalimumab or etanercept to treat rheumatoid arthritis is non-inferior to usual care with regard to major flaring, while resulting in the successful dose reduction or stopping in two thirds of patients.Trial registration Dutch trial register (www.trialregister.nl), NTR 3216.

The FAt Spondyloarthritis Spine Score (FASSS): development and validation of a new scoring method for the evaluation of fat lesions in the spine of patients with axial spondyloarthritis

Introduction

Studies have shown that fat lesions follow resolution of inflammation in the spine of patients with axial spondyloarthritis (SpA). Fat lesions at vertebral corners have also been shown to predict development of new syndesmophytes. Therefore, scoring of fat lesions in the spine may constitute both an important measure of treatment efficacy as well as a surrogate marker for new bone formation. The aim of this study was to develop and validate a new scoring method for fat lesions in the spine, the Fat SpA Spine Score (FASSS), which in contrast to the existing scoring method addresses the localization and phenotypic diversity of fat lesions in patients with axial SpA.

Methods

Fat lesions at pre-specified anatomical locations at each vertebral endplate (C2 lower-S1 upper) were assessed dichotomously (present/absent) on spine MRIs. Two readers independently evaluated MRIs obtained at two time points for 58 patients (Exercise 1), followed by optimization of scoring methodology and reader calibration. Thereafter, the same readers read 135 pairs of MRI scans (Exercise 2; including the 58 pairs from exercise 1 randomly mixed with 77 new pairs).

Results

In Exercise 2, the mean (SD) baseline FASSS score for the two readers was 22.5(29.6) and 21.1(28.0), respectively, and the FASSS change score was 4.2(10.6) and 6.0(12.2). Inter-reader reliability assessed as intra-class correlation coefficients (ICCs) for status and change scores were excellent (0.96 (95% CI (0.94 to 0.97)) and very good (0.86 (0.80 to 0.90)), respectively. The smallest detectable change (SDC) was 3.7 for the 135 patients. Good reliability of change scores was also observed for MRI scans conducted one year apart (ICC 0.74 (95% CI 0.44 to 0.89) and SDC 4.5). For the 58 MRI-pairs assessed in both exercises, inter-reader reproducibility for the total FASSS status score improved from very good (ICCs: 0.89 (95% CI: 0.81 to 0.93) in exercise 1 to excellent in exercise 2 (0.96 (0.93 to 0.98)), and improved substantially for the total change score (from 0.67 (0.51 to 0.80) to 0.83 (0.73 to 0.90).

Conclusions

FASSS meets essential validation criteria for quantification of a common structural abnormality in clinical trials of axial spondyloarthritis.

Development and preliminary validation of the spondyloarthritis research consortium of Canada magnetic resonance imaging sacroiliac joint structural score

OBJECTIVE

There is an unmet need for reliable assessment of structural progression in the sacroiliac joints (SIJ) of patients with spondyloarthritis (SpA), but radiography is unreliable and lacks responsiveness. We aimed to develop and validate a new scoring method for structural lesions based on magnetic resonance imaging (MRI), the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ Structural Score (SSS).

METHODS

The SSS method for assessment of structural lesions is based on T1-weighted spin echo MRI, validated lesion definitions, slice selection according to well-defined anatomical principles, and dichotomous scoring (lesion present/absent) of 5 consecutive slices through the cartilaginous portion of the joint. Scoring ranges are fat metaplasia (0-40), erosion (0-40), backfill (0-20), and ankylosis (0-20). We progressively conducted 3 validation exercises with 2-4 readers on baseline, and either 2-year (exercises 1 and 2) or 1-year (exercise 3) scans from 147 patients with SpA assessed blinded to timepoint. Interobserver reliability was assessed by intraclass correlation coefficient (ICC) and smallest detectable change (SDC).

RESULTS

Interobserver reliability for status score was good to excellent for ankylosis (ICC 0.79-0.98), consistently good for fat metaplasia (ICC 0.71-0.78), moderate to good for erosion (ICC 0.58-0.62), and fair to good for backfill (ICC 0.35-0.66). Reliability for change scores was moderate to good for all structural lesions despite the relatively small changes in scores, and was highest for fat metaplasia when both ICC and SDC values were compared.

CONCLUSION

The new SPARCC MRI SSS method can detect structural changes in the SIJ with acceptable reliability over a 1-2-year timeframe, and should be further validated in patients with SpA.

Tumor necrosis factor inhibitor therapy but not standard therapy is associated with resolution of erosion in the sacroiliac joints of patients with axial spondyloarthritis

Introduction

Radiography is an unreliable and insensitive tool for the assessment of structural lesions in the sacroiliac joints (SIJ). Magnetic resonance imaging (MRI) detects a wider spectrum of structural lesions but has undergone minimal validation in prospective studies. The Spondyloarthritis Research Consortium of Canada (SPARCC) MRI Sacroiliac Joint (SIJ) Structural Score (SSS) assesses a spectrum of structural lesions (erosion, fat metaplasia, backfill, ankylosis) and its potential to discriminate between therapies requires evaluation.

Methods

The SSS score assesses five consecutive coronal slices through the cartilaginous portion of the joint on T1-weighted sequences starting from the transitional slice between cartilaginous and ligamentous portions of the joint. Lesions are scored dichotomously (present/absent) in SIJ quadrants (fat metaplasia, erosion) or halves (backfill, ankylosis). Two readers independently scored 147 pairs (baseline, 2 years) of scans from a prospective cohort of patients with SpA who received either standard (n = 69) or tumor necrosis factor alpha (TNFα) inhibitor (n = 78) therapy. Smallest detectable change (SDC) was calculated using analysis of variance (ANOVA), discrimination was assessed using Guyatt’s effect size, and treatment group differences were assessed using t-tests and the Mann–Whitney test. We identified baseline demographic and structural damage variables associated with change in SSS score by univariate analysis and analyzed the effect of treatment by multivariate stepwise regression adjusted for severity of baseline structural damage and demographic variables.

Results

A significant increase in mean SSS score for fat metaplasia (P = 0.017) and decrease in mean SSS score for erosion (P = 0.017) was noted in anti-TNFα treated patients compared to those on standard therapy. Effect size for this change in SSS fat metaplasia and erosion score was moderate (0.5 and 0.6, respectively). Treatment and baseline SSS score for erosion were independently associated with change in SSS erosion score (β = 1.75, P = 0.003 and β = 0.40, P < 0.0001, respectively). Change in ASDAS (β = −0.46, P = 0.006), SPARCC MRI SIJ inflammation (β = −0.077, P = 0.019), and baseline SSS score for fat metaplasia (β = 0.085, P = 0.034) were independently associated with new fat metaplasia.

Conclusion

The SPARCC SSS method for assessment of structural lesions has discriminative capacity in demonstrating significantly greater reduction in erosion and new fat metaplasia in patients receiving anti-TNFα therapy.