肥満と関節リウマチ重症度の関連

肥満は関節リウマチの重症度と合併症に関連するという論文を紹介します。

Sofia Ajeganova, et al:Obesity is associated with worse disease severity in rheumatoid arthritis as well as with co-morbidities – a long-term follow-up from disease onset. Arthritis Care & Research DOI: 10.1002/acr.21710

リサーチクエスチョンは以下の通りです。

P：関節リウマチ（RA）患者で
E：肥満（BMI30以上もしくは28以上）を認める場合
C：肥満を認めない場合と比較して
O：関節リウマチの重症度が高い（DAS28）

結果ですが、1596人のRA患者のうち、開始時の12.9％、フォローアップ時の15.8％にBMI30以上の肥満を認めました。BMI30以上もしくは28以上のRA患者は、それ以下の患者と比較して、より疾患の活動度が高く、持続的寛解が少なく、痛みと全体の健康状態が悪かったです。

また、BMIは高血圧、糖尿病、慢性肺疾患、狭心症、急性心筋梗塞と独立して関連していました。禁煙や食事変更といったライフスタイルの観察期間中の変化は、予後に影響を与えませんでした。以上より、肥満は関節リウマチの重症度と合併症と関連するという結論です。

COPD、CKD、CHFなど慢性臓器不全・炎症性疾患ではObesity Paradoxの存在が指摘されていますが、関節リウマチの場合、Obesity Paradoxはなさそうですね。関節リウマチでは、るいそうも肥満も問題で、適正な体重・筋肉量を保つことが最も重要だと思われます。

参考資料：関節リウマチにおけるBMIとインフリキシマブの効果の関連。BMIが高い患者では疾患活動度の改善が有意に低い関連を認めました。
http://rehabnutrition.blogspot.jp/2011/02/bmi.html

Abstract
Objective: To determine the association of obesity, defined as BMI≥30 or ≥28 kg/m2 or by waist circumference (WC), on disease activity and severity as well as its relation to comorbidities in rheumatoid arthritis (RA).

Methods: The study population comprised 1596 patients with early RA, mean(SD) age 55.6(14.6) years, 67.8% women, who had been included in the BARFOT observational study 1992-2006. In 2010, data on life-style factors and comorbidities were collected through a postal questionnaire, answered by 1391 patients. Clinical outcomes were DAS28, sustained remission, physical function (HAQ), VAS pain and global health, as well as predefined comorbidities.

Results: After mean(SD) of 9.5(3.7) years, BMI had increased from 25.4(4.2) to 26.0(4.5) kg/m2, p=0.000. The prevalence of BMI≥30 was 12.9% at baseline and 15.8% at follow-up. In multivariable regression, BMI and obesity defined as BMI>30 or >28, at both inclusion and at survey were independently associated with higher disease activity, fewer in sustained remission, higher HAQ, more pain and worse general health. Also, BMI and obesity independently conferred to higher odds for being diagnosed with hypertension, diabetes mellitus and chronic pulmonary disease. Further, BMI and WC were independently associated with angina pectoris/AMI/coronary revascularization. In contrast, none of the examined obesity variables conferred to prevalence of stroke or transient ischemic attack. Life-style changes during observational period, as quit smoking or diet change, had no impact on the outcomes.

Conclusion: Obesity was associated with worse RA-disease outcomes and higher prevalence of comorbidities. Body measurements are recommended to improve prediction of disease course. © 2012 by the American College of Rheumatology