Background The assessment of factors that influence survival on anti-TNF therapy in patients with AS is still limited but suggests that gender, functional status, symptom duration, and fatigue are most important while data on objective parameters of inflammation suggests no effect1. There has been no data reported evaluating MRI parameters of inflammation and structural damage on long-term survival on treatment. Remission of inflammation detected by MRI could predict survival on anti-TNF therapy. This could impact the role of MRI in selection of patients for treatment with anti-TNF and subsequent monitoring of response.
Objectives 1. To determine the factors influencing survival on anti-TNF therapy in real world practice. 2. To determine the role of MRI parameters of inflammation and structural damage on drug survival.
Methods In the FOllow-up Research Cohort in AS (FORCAST), AS patients from Northern Alberta attending community and academic practices are assessed for clinical and laboratory outcomes every 6 months, radiography at baseline and 2 years, MRI at baseline, at 3-6 months for patients starting anti-tumor necrosis factor alpha (anti-TNFα), and annually. MRI inflammation was assessed using SPARCC SIJ and Spine scores while structural change was assessed independently using the SSS scores for fat metaplasia, erosion, backfill, ankylosis and the FASSS score for fat metaplasia in the spine. We used univariate and multivariate regression to assess patient demographics, smoking, B27, NSAID utilization, and baseline CRP, ASDAS, mSASSS, SPARCC scores, SSS and FASSS scores on drug survival. We also assessed early attainment post-treatment of CRP<6mg/L, ASADAS<1.3, and SPARCC scores <2 as predictors of survival.
Results We recruited 463 patients on anti-TNF, mean (SD) age 41.3 (12.7) years, 74.7% males, mean (SD) symptom duration 18.2 (11.6) years, mean (SD) duration of follow up on anti-TNF 42.6 (34.4) months, mean (SD) survival on first anti-TNF 20.5 (25) months. The number failing the first anti-TNF was 27%, of which 32% was for lack of efficacy (LOE), and 27% for adverse events. There were 16 primary and 110 secondary failures. 165 patients had MRI at baseline and 153 had at least one follow up MRI. Univariate analysis showed that male sex (p=0.029), and post-treatment scores of SPARCC SIJ score <2 (p=0.041), ASDAS<1.3 (p=0.034), and CRP<6mg/L (p=0.027) were significant predictors of drug survival. In multivariate analysis of clinical predictors, SPARCC SIJ < (adjusted OR=2.2[1.02-4.74]; p=0.043) was a significant predictor.
Conclusions From an extensive array of patient demographic and disease severity variables, early remission of MRI inflammation may best predict survival on anti-TNF.
Glintborg et al. Ann Rheum Dis 2013; 72: 1149-55
Disclosure of Interest None declared