**4. Natural history of MHE**

The incidence of MHE increases with progression of liver disease. With time, MHE may improve or progress to OHE [36, 37]. The rate of progression to overt HE was much higher in patients with MHE and Child-Pugh score > 6 than in those with MHE and Child-Pugh score ≤ 6 [38]. Moreover, MHE in patients with large portalsystemic shunts had a better outcome due to preserved hepatocytes [39]. Real probability of OHE at 3 years was 56% in patients of liver cirrhosis in the presence of MHE and 8% for those without MHE [37]. In addition, existence of MHE in cirrhosis associated with shorter survival time and increased mortality rate compared to those without MHE [40–43].
