Arthritis & Rheumatism, Volume 60,
October 2009 Abstract Supplement

The 2009 ACR/ARHP Annual Scientific Meeting
Philadelphia October 16-21, 2009.


Anti Tumour Necrosis Factor Alpha Therapy Improves Insulin Resistance in Normal-Weight but Not in Obese Patients with Rheumatoid Arthritis

Stavropoulos-Kalinoglou1,  Antonios, Metsios1,  Giorgos S., Panoulas2,  Vasileios F., Koutedakis1,  Yiannis, Kitas2,  George D.

University of Wolverhampton, Walsall, United Kingdom
Dudley Group of Hospitals NHS Foundation Trust, Dudley, United Kingdom

Purpose:

Insulin resistance (IR) associates with obesity and is a predisposing factor for cardiovascular disease (CVD) and type-II diabetes. In Rheumatoid Arthritis (RA), IR is common and is a potential contributor to the increased CVD risk of these patients. Anti tumour necrosis factor alpha (anti-TNFa) therapies are suggested to reduce CVD risk in RA; they have also been suggested to improve insulin kinetics. However, obesity – a potent contributor to IR – might influence the way anti-TNFa therapy affects insulin kinetics in RA. The aim of this longitudinal study was to compare the effects of anti-TNFa therapy on insulin kinetics between normal weight and obese individuals with and without IR.

Method:

Patients embarking on anti-TNFa treatment, who were of normal-weight but had IR (N+IR), or were obese and had IR (O+IR), were invited to participate. Assessments included body mass index (BMI), CVD risk factors and RA disease characteristics before and following six months of anti-TNFa treatment. The results of the N+IR and O+IR patients were compared to age-, gender-, BMI-, disease duration- and smoking status-matched normal-weight patients without IR (N-IR) and obese patients without IR (N-IR) respectively. IR was defined as a HOMA (Homeostasis Model of Assessment) >= 2.5, or a QUICKI (quantitative insulin-sensitivity check index) <= 0.333. Patients with diabetes mellitus, or using anti-diabetic medication were excluded from the study. A total of 20 patients (16 women, age range 45–69), 5 in each of the groups, were assessed for this study.

Results:

One-way Analysis of Variance (ANOVA) found no differences in BMI in any of the groups following six months of treatment (p>0.05). Inflammation and disease activity were significantly reduced in all groups (p<0.05) but to a similar extend (p for differences between groups >0.05 in all cases). Repeated measures ANOVA showed that the treatment resulted in greater (beneficial) changes in HOMA (p=0.031), QUICKI (p=0.025), systolic BP (p=0.048) and triglycerides (p=0.034) in N+IR patients compared to N-IR. In the obese groups, there was only a non-significant trend of improvement in IR [O+IR (p=0.075); O-IR (p=0.082)]. There were no differences in the magnitude of improvements between these two groups in HOMA, QUICKI, or any other CVD risk factors.

Conclusion:

Anti-TNFa therapy improves insulin kinetics in normal weight but not in obese RA patients with IR. This suggests that in normal weight RA patients, IR associates mostly with active inflammation and is largely reversible, while in obese RA patients IR associates mostly with obesity and does not reverse with potent anti-inflammatory therapy, such as the anti-TNFs. This has obvious implications for CVD prevention strategies in RA.

To cite this abstract, please use the following information:
Stavropoulos-Kalinoglou, Antonios, Metsios, Giorgos S., Panoulas, Vasileios F., Koutedakis, Yiannis, Kitas, George D.; Anti Tumour Necrosis Factor Alpha Therapy Improves Insulin Resistance in Normal-Weight but Not in Obese Patients with Rheumatoid Arthritis [abstract]. Arthritis Rheum 2009;60 Suppl 10 :1603
DOI: 10.1002/art.26677

Abstract Supplement

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