Consultancy Corner: Insulin sensitivity key to managing fatty liver condition

It is the most common cause of abnormal liver tests in the community and is closely associated with his ‘big brother’ metabolic syndrome (MS), which comprises of central obesity, Type 2 diabetes mellitus (Type 2 DM), hypertension and hyperlipidemia. 

NAFLD may be present in at least 50-70% of patients with type 2 DM. India being the diabetic capital one would anticipate much higher prevalence of NAFLD. In patients with NAFLD, the prevalence of MS is around 40%.  NAFLD is emerging as an important health issue of concern in both adults and children because it increases the risk of type 2 diabetes mellitus, hypertension, ischaemic heart disease and death, significantly. Studies are being conducted around in many liver centers to identify genetic, ethnic and environmental risk factors for NAFLD and MS. 

NAFLD, the liver manifestation of MS is characterised by steatosis (fatty liver). Progressive steatosis leads to non-alcoholic steatohepatitis (NASH) in at least 40% of patients which is characterised by hepatic inflammation. Long standing inflammatory mileu leads to fibrosis (liver scarring) and eventually to cirrhosis in approximately 10% of patients. Studies show that many cases of ‘cryptogenic cirrhosis’ are probably due to ‘burnt out’ NASH. In addition, NASH cirrhosis increases the risk of hepatocellular carcinoma by several folds. Recent evidence shows an increased prevalence of colonic neoplasms in patients with NASH. 

Like most chronic liver conditions, patients with NAFLD are asymptomatic until late in 

their illness. Majority of them are diagnosed rather incidentally. ‘Fatigue’ may be observed in some but being a non-specific symptom, it may be over looked. Blood tests may show slightly elevated transaminases such as aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT). However, the sensitivity of liver enzymes is poor for the detection of NAFLD. Furthermore, these enzymes do not differentiate between simple steatosis and steatohepatitis. In a recent Italian study, biopsy proven NASH was present in up to 60% of patients with type 2 diabetes with normal liver enzymes. Ultrasound abdomen may show a ‘bright echogenic liver’ suggestive of increased echogenicity. The advantages of ultrasound are, it is readily available, non-invasive and inexpensive. However, it is not a sensitive test until the steatosis is moderate to severe, result may vary depending on the observer. Presence of abdominal obesity can further reduce its accuracy. To further complicate this issue, other rare conditions like iron over load can also increase the echogenicity of the liver.  In addition, ultrasound lacks specificity for excluding hepatic steatosis. 

Measures to improve insulin sensitivity remain the key for both NAFLD and MS management. This treatment also holds good addressing cardiovascular risks. However, the lack of single effective therapy led to a multi-dimensional treatment approach such as life style modification, weight loss, change in dietary habit and exercise. Unfortunately, most studies in NAFLD treatment are only performed to evaluate short- term benefit and there is a lack of long term data.