Prognosis
The average progression rate from one stage of liver fibrosis to the next in humans with NASH is estimated to be seven years, compared to 14 years with NAFLD. The course of progression varies with different clinical manifestations among individuals. Fibrosis in humans with NASH progressed more rapidly than in humans with NAFLD. Obesity predicts a worse long-term outcome than for lean individuals. In the Asia-Pacific region, about 25% of NAFLD cases progress to NASH under three years, but only a low proportion (3.7%) develop advanced liver fibrosis. An international study showed that people with NAFLD had a 10-year survival rate of 81.5%.NAFLD is a risk factor for fibrosis, hypertension, chronic kidney disease, atrial fibrillation, myocardial infarction, ischemic stroke, and death from cardiovascular causes based on very-low to low-quality evidence from observational studies. Although NAFLD can cause cirrhosis and liver failure and liver cancer, most deaths among people with NAFLD are attributable to cardiovascular disease. According to a meta-analysis of 34,000 people with NAFLD over seven years, these individuals have a 65% increased risk of developing fatal or nonfatal cardiovascular events when compared to those without NAFLD.NAFLD and NASH increase the risk of liver cancer. Cirrhosis and liver cancer induced by NAFLD were the second cause of liver transplantation in the US in 2017. Liver cancer develops in NASH in the absence of cirrhosis in 45% in the cases, and people with NASH cirrhosis have an increased risk of liver cancer.
According to AASLD guidelines, "omega-3 fatty acids should not be used as a specific treatment of NAFLD or NASH, but they may be considered to treat hypertriglyceridemia for patients with NAFLD". Surgery
Bariatric surgery is an effective method for obese and diabetic individuals with NAFLD to induce weight loss and reduce or resolve NASH inflammation, including fibrosis, and improve longevity. For the AASLD, bariatric surgery can be considered only for NASH on a case-by-case basis by an experienced bariatric surgery program. Indeed, some individuals might develop new or worsened features of NAFLD.About 92% of people with NAFLD saw an improvement in steatosis and 70% a complete resolution after bariatric surgery.A preoperative diet such as a low-calorie diet or a very-low-calorie diet is usually recommended to reduce liver volume by 16–20%. Preoperative weight loss is the only factor associated with postoperative weight loss. Preoperative weight loss can reduce operative time and hospital stay, although there is insufficient evidence whether preoperative weight loss reduces long-term morbidity or complications. Weight loss and decreases in liver size may be independent of the amount of calorie restriction.The APWG on NAFLD recommends bariatric surgery as a treatment option for those with class II obesity (BMI >32.5 kg/m2 for Asians, 35 kg/m2 for Caucasians). They consider its effects on improving liver-related complications as unproven yet, but it effectively increases longevity by improving cardiovascular factors.Surgery carries more risks for individuals with NASH cirrhosis, with a review estimating overall morbidity to be 21%.