Page 36 - EASL POSTGRADUATE COURSE
P. 36
Challenges in the diagnosis of NASH
NASH IN LEAN PATIENTS
Vincent Wong
Institute of Digestive Disease,
The Chinese University of Hong Kong,
Hong Kong, China
E-mail: wongv@cuhk.edu.hk
Take home messages
• NASH and advanced fibrosis occur in lean patients, albeit at a lower prevalence.
• Most lean patients with NASH have recent weight gain, other metabolic risk factors or insulin
resistance.
• Since lean patients are less likely to have advanced disease, non-invasive tests of NASH and fibrosis
are preferred.
• Lifestyle intervention remains the most important treatment for NASH in lean patients.
Pharmacological treatment may be considered in selected cases.
Introduction
NAFLD is the most common chronic liver disease and has rapidly become an important cause of liver
failure and HCC. It is strongly associated with obesity and MetS. However, a small but significant
proportion of patients develop NAFLD despite normal body mass index (BMI).They are usually referred
to as having lean or non-obese NAFLD. Here, we will discuss the epidemiology, clinical significance and
management of lean NAFLD.
What is meant by lean?
Worldwide, BMI is used to define obesity. In western countries, the definitions of overweight and obesity
are BMI of 25-30 and ≥30 kg/m2, respectively.While easy to perform and calculate, BMI is an imperfect
assessment of adiposity and cannot distinguish between muscle mass and fat mass. Besides, the pattern
of fat distribution differs among races. For example, visceral obesity and metabolic complications occur
at a lower BMI in Asians. Therefore, the measurement of waist circumference can provide additional
information on fat distribution. Ethnic-specific definitions of obesity and central obesity have also been
recommended (Tables 1 and 2).
Table 1. World Health Organization guidance on BMI (kg/m2) thresholds (2004).
White Europeans Asians Description
<18.5 <18.5 Underweight
18.5-25 18.5-23 Increasing but acceptable risk
25-29.9 23-27.5 Increased risk
≥30 ≥27.5 High risk
36 Postgraduate Course Syllabus • Metabolic Liver Disease
NASH IN LEAN PATIENTS
Vincent Wong
Institute of Digestive Disease,
The Chinese University of Hong Kong,
Hong Kong, China
E-mail: wongv@cuhk.edu.hk
Take home messages
• NASH and advanced fibrosis occur in lean patients, albeit at a lower prevalence.
• Most lean patients with NASH have recent weight gain, other metabolic risk factors or insulin
resistance.
• Since lean patients are less likely to have advanced disease, non-invasive tests of NASH and fibrosis
are preferred.
• Lifestyle intervention remains the most important treatment for NASH in lean patients.
Pharmacological treatment may be considered in selected cases.
Introduction
NAFLD is the most common chronic liver disease and has rapidly become an important cause of liver
failure and HCC. It is strongly associated with obesity and MetS. However, a small but significant
proportion of patients develop NAFLD despite normal body mass index (BMI).They are usually referred
to as having lean or non-obese NAFLD. Here, we will discuss the epidemiology, clinical significance and
management of lean NAFLD.
What is meant by lean?
Worldwide, BMI is used to define obesity. In western countries, the definitions of overweight and obesity
are BMI of 25-30 and ≥30 kg/m2, respectively.While easy to perform and calculate, BMI is an imperfect
assessment of adiposity and cannot distinguish between muscle mass and fat mass. Besides, the pattern
of fat distribution differs among races. For example, visceral obesity and metabolic complications occur
at a lower BMI in Asians. Therefore, the measurement of waist circumference can provide additional
information on fat distribution. Ethnic-specific definitions of obesity and central obesity have also been
recommended (Tables 1 and 2).
Table 1. World Health Organization guidance on BMI (kg/m2) thresholds (2004).
White Europeans Asians Description
<18.5 <18.5 Underweight
18.5-25 18.5-23 Increasing but acceptable risk
25-29.9 23-27.5 Increased risk
≥30 ≥27.5 High risk
36 Postgraduate Course Syllabus • Metabolic Liver Disease
