Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Relationship between Active Inflammatory Lesions in the Spine and Sacroiliac Joints and New Development of Fatty Infiltration on Whole-Body MRI in Early Axial SpondyloarthritisResults of the ESTHER Trial at Week 48.

Song1,  In-Ho, Hermann2,  Kay-Geert, Haibel1,  Hildrun, Althoff2,  Christian, Listing3,  Joachim, Freundlich4,  Bruce, Rudwaleit1,  Martin

Charite Campus Benjamin-Franklin, Medical Clinic I, Rheumatology, Berlin, Germany
Charite Campus Mitte, Radiology, Berlin, Germany
German Rheumatism Research Center, Berlin, Germany
Wyeth/Pfizer Inc., Collegeville, PA

Purpose:

To investigate the relationship between resolution of active inflammatory lesions on whole-body magnetic resonance imaging (wb-MRI) and new development of fatty infiltration in early axial spondyloarthritis (SpA) treated either with etanercept (ETA) or sulfasalazine (SSZ).

Method:

Axial SpA patients enrolled in a randomized controlled trial (1) were treated with ETA (n= 40) vs. SSZ (n= 36) over 48 weeks. All patients showed active inflammatory lesions (bone marrow edema) on wb-MRI in either the sacroiliac joints (SIJ) and/or the spine at baseline (BL). Wb-MRIs were performed at weeks 0, 24 and 48 and were scored for active inflammation and fatty infiltration in the four quadrants of each SIJ and the 23 vertebral units (VUs) of the spine. Scoring was performed by two radiologists, blinded for treatment arm and MRI time point. Generalized estimation equations were used to calculate confidence intervals by taking repeated measurements within individual patients into account.

Results:

There was a very low rate of new fatty infiltration of about 1% (0.8% for SIJ quadrants and 1.7% for VUs) if there was no previous inflammation in the bone (see table). There was a good relationship between disappearance of inflammation and the appearance of fatty infiltration: if inflammation resolved fatty infiltration occurred in 17.3% (SIJ quadrants) and 19.1% (VUs). If inflammation did not resolve fatty infiltration occurred much less frequently: 8.4% (SIJ quadrants) and 5.8% (VUs) (p= 0.0001 for SIJ and p= 0.1 for VUs for the difference between resolved and persistent inflammation group, see table). Interestingly, new fatty infiltration occurred more frequently in the ETA group (26 VU sites and 33 SIJ sites) compared to the SSZ group (8 VU sites and 12 SIJ quadrant sites). This was in concordance with the significantly higher increase of the mean fatty infiltration score in the ETA (mean fat infiltration score 1.86 at baseline vs. 2.56 at week 24 for the SIJ, and 3.88 vs. 4.60 for the spine) compared to the SSZ (mean fat infiltration score 1.73 at baseline vs. 1.76 at week 24 for the SIJ, and 3.34 vs. 3.51 for the spine, respectively) group (p= 0.018 and p= 0.006 for the differences).

Conclusion:

These data indicate that there is a close interaction between inflammation, TNF-blockade and fatty infiltration of subchondral bone marrow. The higher amount of fatty infiltration in the ETA group is probably due to the effective suppression of active inflammation. The molecular mechanisms of these interactions have to be further investigated.

Table. Development of fatty infiltration at week 48 according in development of active inflammation

LocationActive inflammationNew fatty infiltration at week 48
  Number%[95% confidence intervals]
Spine-vertebral unitsNo active inflammation at any time13/15550.8%[0.4%–1.8%]
 Active lesion at baseline and resolution at week 4813/7517.3%[8.5%–32.2%]
 Persistent active inflammation8/958.4%[3.8%–17.5%]
SIJ-QuadrantsNo active inflammation at any time4/2411.7%[0.4%–7.5%]
 Active lesion at baseline and resolution at week 4829/15219.1%[12.4%–28.1%]
 Persistent active inflammation12/2075.8%[2.8%–11.3%]

(1)Song, I.-H. et al. EULAR 2010, OP 0029

To cite this abstract, please use the following information:
Song, In-Ho, Hermann, Kay-Geert, Haibel, Hildrun, Althoff, Christian, Listing, Joachim, Freundlich, Bruce, et al; Relationship between Active Inflammatory Lesions in the Spine and Sacroiliac Joints and New Development of Fatty Infiltration on Whole-Body MRI in Early Axial SpondyloarthritisResults of the ESTHER Trial at Week 48. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :669
DOI: 10.1002/art.28437

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