外科患者の肥満パラドックス

外科患者の肥満パラドックスに関するレビュー論文を紹介します。

Tabita M. Valentijn , Wael Galal , Elke K.M. Tjeertes , Sanne E. Hoeks , Hence J. Verhagen , Robert Jan Stolker. The obesity paradox in the surgical population. The Surgeon, doi:10.1016/j.surge.2013.02.003

肥満バラドックスは心臓外科患者と非心臓外科患者に認めました。低栄養（るいそう）と病的肥満（BMI40以上）の患者は、術後も長期フォローアップ後も最も予後が悪かったです。

肥満バラドックスの原因として、除脂肪体重増加、（保護作用のある）末梢脂肪、炎症減少、遺伝、心血管疾患リスク因子の減少が考えられますが、おそらく未知の要因も関与していると思われます。

肥満パラドックスといっても、病的肥満では予後が悪く、太っていれば太っているほどよいという結果ではなかったので、慢性呼吸不全や慢性心不全などによる肥満パラドックスとは少し異なる印象です。肥満パラドックスという言葉を同じように使うべきか微妙な気もします。

Abstract

Background

Despite the medical hazards of obesity, recent reports examining body mass index (BMI) show an inverse relationship with morbidity and mortality in the surgical patient. This phenomenon is known as the ‘obesity paradox’. The aim of this review is to summarize both the literature concerned with the obesity paradox in the surgical setting, as well as the theories explaining its causation.

Methods

PubMed was searched to identify available literature. Search criteria included obesity paradox and BMI paradox, and studies in which BMI was used as a measure of body fat were potentially eligible for inclusion in this review.

Results

The obesity paradox has been demonstrated in cardiac and in non-cardiac surgery patients. Underweight and morbidly obese patients displayed the worse outcomes, both postoperatively as well as at long-term follow-up. Hypotheses to explain the obesity paradox include increased lean body mass, (protective) peripheral body fat, reduced inflammatory response, genetics and a decline in cardiovascular disease risk factors, but probably unknown factors contribute too.

Conclusions

Patients at the extremes of BMI, both the underweight and the morbid obese, seem to have the highest postoperative morbidity and mortality hazard, which even persists at long-term. The cause of the obesity paradox is probably multi-factorial. This offers potential for future research in order to improve outcomes for persons on both sides of the ‘optimum BMI’.