Elsevier

Journal of Hepatology

Volume 45, Issue 4, October 2006, Pages 600-606
Journal of Hepatology

Special article
Hepatic histology in obese patients undergoing bariatric surgery

https://doi.org/10.1016/j.jhep.2006.06.013Get rights and content

Background/Aims

Obesity is one of the most important clinical associations with non-alcoholic steatohepatitis (NASH). Our aim was to assess the prevalence of non-alcoholic fatty liver disease (NAFLD)/NASH in morbidly obese patients and the risk factors to more aggressive liver disease in this population.

Methods

Review of available studies on prevalence of NAFLD/NASH in severely obese patients submitted to bariatric surgery.

Results

Twelve observational and transversal studies were included, with consecutive recruitment, and prospective evaluation of data, summing 1620 patients with severe obesity. Prevalence of steatosis and NASH was 91% (range: 85–98%) and 37% (24–98%), respectively, with unexpected cirrhosis in 1.7% (1–7%). NASH was not related with age or body mass index, but there was an association between male sex and NASH/hepatic fibrosis. Diabetes mellitus and insulin resistance were the conditions most frequently associated with NASH, and hypertension with advanced hepatic fibrosis.

Conclusions

There is a very high prevalence of NAFLD in asymptomatic morbidly obese patients, more than one-third presenting histological criteria for NASH. This review underscores the large variations in prevalence of NASH between studies, calling for the need for a better agreement in the use of the histological criteria.

Introduction

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver disease that encompasses steatosis alone to non-alcoholic steatohepatitis (NASH) and can progress to cirrhosis and liver failure. NAFLD is one of the most important forms of liver disease in the developed countries, occurring in 20% to 25% of the general population [1], whereas NASH occurs in about 3% [2], [3].

Obesity and insulin resistance (IR) are believed to exert the main pathophysiological role in the development of NAFLD [4], [5], [6], [7], [8]. The prevalence of obesity has increased tremendously in the last half century [9]. A further increase in the prevalence of NAFLD is expected in the future. However, until recently, few data were available on the prevalence of NAFLD and NASH in severely obese patients, defined as a body mass index (BMI) higher than 35 kg/m2. Further, the risk factors for a more aggressive liver disease in this population have yet to be clearly defined.

In the last 5 years, investigators have been trying to identify the real prevalence of NAFLD and NASH in the population of severely obese patients admitted to bariatric surgery, with systematic liver biopsy at the time of surgery. Although most studies had a very similar design, still their results were quite dissimilar. Thus, we conducted an in-depth review of available studies on the prevalence and risk factors for NAFLD in morbidly obese subjects, in order to summarize and evaluate the published data and to discuss discrepant findings.

Section snippets

Materials and methods

We conducted a literature search using MEDLINE and Current Contents to identify relevant articles published in any language, until December 2005. We also manually searched the references of retrieved articles to identify additional relevant published studies. Search criteria included MEDLINE medical subject heading terms for NAFLD, NASH, morbidly obesity and bariatric surgery. Studies were eligible if they reported prevalence data regarding systematic liver biopsy in morbidly obese patients

Results

Seventeen studies were selected [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], of which five [10], [17], [20], [21], [26] were excluded because of their retrospective design or other methodological issues. The remaining twelve publications were transversal, observational studies with a prospective and consecutive recruitment of patients, enrolling a total of 1620 severely obese patients. Their main characteristics are summarized in Table 1.

Discussion

The present review found an enormous discrepancy in the prevalence of NASH in individuals with severe obesity. This is unexpected, given the fact that study design and patients demographics were quite similar in all studies. The first logical explanation would be a difference in geographic location with associated ethnic or dietary/life style differences. In fact, if we consider studies from the USA alone, there is a more uniform prevalence of NASH, with a relatively lower prevalence. On the

References (37)

  • G. Bedogni et al.

    Prevalence of and risk factors for nonalcoholic fatty liver disease: the Dionysos nutrition and liver study

    Hepatology

    (2005)
  • I.R. Wanless et al.

    Fatty liver hepatitis (steatohepatitis) and obesity: an autopsy study with analysis of risk factors

    Hepatology

    (1990)
  • A. Braillon et al.

    Liver in obesity

    Gut

    (1985)
  • G. Marchesini et al.

    Nonalcoholic fatty liver disease: a feature of the metabolic syndrome

    Diabetes

    (2001)
  • K.M. Flegal

    Trends in body weight and overweight in the U.S. population

    Nutr Rev

    (1996)
  • F.H. Luyckx et al.

    Liver abnormalities in severely obese subjects: effect of drastic weight loss after gastroplasty

    Int J Obes Relat Metab Disord

    (1998)
  • P. Marceau et al.

    Liver pathology and the metabolic syndrome X in severe obesity

    J Clin Endocrinol Metab

    (1999)
  • J. Poniachik et al.

    [Obesity: risk factor for steatohepatitis and hepatic fibrosis]

    Rev Med Chil

    (2002)
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