Chronic Disease Management of Steatotic Liver Disease ("Fatty Liver")
- Nov 5, 2023
- 6 min read
Updated: Dec 3, 2023
Non-Alcohol Fatty Liver Disease (NAFLD) is often seen in the ultrasound department, as it is a primary diagnostic tool which provides critical information for disease detection, evaluation, and treatment planning. NASH is the active form of NAFLD and results in fibrosis (stages F0 through F4), leading to cirrhosis, hepatocellular carcinoma (HCC), and end-stage liver failure which may require surgery or lead to mortality (Alberta Health Services, 2023). Understanding NAFLD and NASH risk factors can have significant effects on disease progression and associated complications. Early identification and detection of NAFLD in high-risk patients is critical to providing proper chronic disease management and evaluation programs for disease progression (Sanyal, et.al., 2021).
NAFLD is estimated to affect 1 billion people world-wide and affects approximately 31% of North Americans (Sanyal, et. al., 2023). NAFLD and NASH rates have been increasing globally, from 20% in the 1980’s to 31% in 2016 (Sanyal, et. al., 2023). NASH is the second leading cause of liver transplants, after primary hepatocellular carcinoma (HCC) (Sanyal, et. al., 2021).
Risk Factors
NAFLD/NASH is a complex multisystemic chronic disease with multiple risk factors. In patients with NASH/NAFLD, the primary cause of death is cardiovascular disease followed by cancer and then liver disease (AHS, 2019). However, in the presence of cirrhosis, end-stage liver disease becomes the primary cause of death (Canada Liver Foundation).
Individual
Multiple risk factors contribute to the development and progression of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH), including genetic predisposition, infections (hepatitis B and C), Wilson’s disease, medications (steroids or tamoxifen) or lifestyle behaviours (overeating, obesity, and alcohol use) (Cotter & Rinella, 2020). The more co-existing risk factors, the greater the likelihood of severe and rapid disease progression and complication of NAFLD, including early onset of fibrosis or Hepatocellular carcinoma (HCC) (Sanyal, et. al., 2023; Cotter & Rinella, 2020).
Various individual risk factors such as age and race are associated with the prevalence of NAFLD and NASH, as well as distinct high-risk sub-populations. Global rates are low throughout Africa and are most abundant in the Middle East and South America (Sanyal, et. al., 2023). Primary diagnosis of NAFLD and NASH occurs around 40-50 years of age and is rare but not unheard of among younger populations (AHS, 2023). Hispanics tend to have generalized increase rates of NAFLD, while Black populations have a low incidence rate (Sanyal, et. al., 2021). It is noteworthy that non-obese Asian males are more susceptible to developing NAFLD compared to non-obese Asian females, suggesting that obesity is a risk factor but not the sole causal factor (Sanyal et al., 2023; Burak, 2019).
Genetics play a significant role in disease progression, with a heritability factor for NASH/NAFLD between 35-61% (Sanyal, et. al., 2023). Genetic factors such as hepatic insulin resistance, hematomachrosis, and adipocyte disfunction can increase the risk of NAFLD (Sanyal, et. al., 2023). In patients with NASH/NAFLD, cardiovascular disease is the leading cause of death, followed by cancer and liver disease. In the presence of cirrhosis, end-stage liver disease becomes the primary cause of death (GoA, 2023; Sanyal, et. al., 2023).
NASH can alter the gut-biome decreasing the diversity in microbial expression and putting patients at risk for streptococcus and gram-negative bacterial infections. This in turn is linked with malnutrition or susceptibility to medication resistant infections (Sanyal, et. al., 2023).
Neonatal
In non-adult populations, prenatal influences such as maternal elevated BMI and placental factors such as inflammation and oxidative stress can alter a neonatal lipotoxicity increasing risk of early onset NAFLD (Sanyal, et. al., 2023).
Surveillance and Treatment
NAFLD can be diagnosed via blood work, specifically elevated ALT, and imaging such as Ultrasound or MRI, while NASH currently requires a liver biopsy for diagnosis (GoA, 2023). This diagnostic approach can be hindered by social determinants of health and limited access to hospitals for the biopsy procedure (Sanyal, et al., 2023). Non-invasive biomarkers are emerging as an alternative but require broader implementation and physician education (Cotter & Rinella, 2020).
The focus of chronic disease management is through lifestyle modifications. This involves detection of other co-existing disease processes and addressing them through medication management, education, and intervention (AHS, 2023). Secondary risk factors related to lifestyle and community influences such as exercise and nutrition are then addressed, particularly among overweight or obese populations (GoA, 2023). Alcohol consumption is a major contributor to NASH and thus reduction or cessation programs are a vital component of patient-centered care. Finally genetic screening can provide supplementary information to patients and the medical team for individualized risk assessment and awareness programs (Sanyal, et. al., 2021).
Relevance to Practice
Understanding the individual and systemic risk factors for the progression of Non-Alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH) is of paramount importance for effective preventative medicine in the early detection and management of chronic diseases (Health Canada, 2007). NAFLD typically remains asymptomatic until it advances to moderate or severe fibrosis or cirrhosis, significantly impairing liver function (Burak, 2019). Given that the progression of liver disease and fibrosis can accelerate within 4.5 to 7 years of initial detection, it imposes a substantial burden on affected individuals, primary care providers, and publicly funded medical systems in terms of symptom management and addressing underlying risk factors associated with NAFLD/NASH (Burak, 2019).
Shear Wave Elastography
Shear wave elastography (SWE) has become the new gold-standard for non-invasive fibrosis assessment, particularly in conjunction with elevated ALT, low platelets, and co-existing risk factors (Burak, 2019). High risk (>8.0kPa) patients are referred to hepatology for severe disease management, while low risk (<8.0kPa) patients are treated through primary care physicians and multimodality teams to promote lifestyle changes and disease mitigation (Burak, 2019; GoA, 2023). SWE surveillance is recommended every 3 years or sooner in low-risk patients with NAFLD and elevated ALT levels, while moderate scoring may warrant annual SWE at the discretion of the primary care physician and treatment team based on
individual factors (Burak, 2019).
In my role as a sonographer, it is crucial to have a comprehensive understanding of the risk factors and disease progression related to chronic steatotic liver disease. Consistently delivering high-quality imaging for surveillance is pivotal for effective management and treatment planning. This imaging procedure is a routine part of my responsibilities in Alberta and typically accounts for approximately 10% of my daily workload.
Biomarker tests
There are no standardized biomarker tests which provide an alternative, low-risk diagnostic option (Sanyal, et. al., 2023). This can be prohibitive to proper early identification of NASH and fibrosis, which in turn can delay access to medications and intervention. As a result, research to improve biomarker tests has been a primary focus. Studies have demonstrated a high sensitivity and specificity for the following blood tests: ALT (current gold standard but not selective),NIS4, ELF and FibroMeter VCTE (Sanyal, et. al., 2023). As a result, regular 4-panel biomarker screening can be elementary in early detection of NAFLD/NASH, initiative interventional methods in a timely and non-invasive capacity. However, widespread adoption is limited due to primary care physician awareness, education, and uptake.
Nomenclature
Criticism of the traditional nomenclature used for NAFLD and NASH has led to a shift in terminology. The terms "non-alcoholic," "alcoholic," and "fatty" have been criticized for being exclusive and stigmatizing (Rinella, et al., 2023). Consequently, "fatty liver" is being replaced by "steatotic liver disease (SLD)" (Rinella, et al., 2023). New classifications, including MASLD (Metabolic dysfunction-associated steatotic liver disease), MASH (metabolic dysfunction-associated steatohepatitis), and MetALD (metabolic dysfunction and alcohol-associated/related liver disease), are gaining widespread adoption to better account for diverse etiologies and improve patient care.
This new classification system was considered more progressive and descriptive of the disease process, improving patient awareness, promoting positive impact on patient treatment compliance, and improving public awareness without the associated negative stigma (Rinella, et. al, 2023).
Public awareness
In addition to changes in terminology, public health campaigns at multiple levels of health regulation and governmental levels have become commonplace. These include groups such as Liver.ca, Alberta College of Physicians, Canada Liver Foundation, and primary care physician screening pamphlets. The intention is to promote public awareness of the disease and its progression factor while encouraging early detection, regular blood work, and standardized surveillance, as well as fostering a positive environment to discuss risk factor management on a regular and productive basis (Heath Canada, 2007).
Understanding individual risk factors as well as social determinants of health can influence access to appropriate preventative screening, surveillance, disease management, and disease progression. Providing a holistic, preventative model can reduce inequalities, honor autonomy, and decrease complications associated with NAFLD/NASH.
References
Alberta Health Services (2023). Non-Alcoholic Fatty Liver Disease (NAFLD) Primary Care Pathway. Retrieved https://www.albertahealthservices.ca/assets/about/scn/ahs-scn-dh-pathway-nafld.pdf
Burak, K.W. (2019). Non-Alcoholic Fatty Liver Disease (NAFLD) Primary Care Pathway. Alberta College of Family Physicians: Family Medicine Summit. Retrieved https://acfp.ca/wp-content/uploads/2019/03/FRI_1430_1B_NAFLD_Burak.pdf
Canada Liver Foundation. What is Non-Alcoholic Fatty Liver Disease (NAFLD)?. Liver.ca. Retrieved from https://youtu.be/mjlCiAiP2dg
Canada Liver Foundation. What is Non-Alcoholic Steatoheptitis (NASH)? Liver.ca. Retrieved from https://youtu.be/QyHVbi8uets
Cotter, T. G. & Rinella, M. (2020). Nonalcoholic Fatty Liver Disease 2020: The State of Disease. Gastroenteroloy, 158(7): 1851-1864. https://doi.org/10.1053/j.gastro.2020.01.052
Government of Alberta (2023). Non-Alcoholic Steatosis (NASH). MyHealth Alberta. Retrieved https://myhealth.alberta.ca/Health/Pages/conditions.aspx?hwid=ut1396spec
Health Canada (2007). Chronic Disease Prevention and Management. Retrieved from https://www.canada.ca/en/health-canada/services/health-care-system/reports-publications/primary-health-care/chronic-disease-prevention-management.html
Rinella, M., Lazarus, J.V., Ratziu, V. et al., (2023). A Multisociety Delphi Consensus Statement on New Fatty Liver Disease Nomenclature. Hepatology, 10. DOI: 10.1097/HEP.0000000000000520
Sanyal, A.J., Mark, M.D., Van Natta, L, et. al., (2021). Prospective Study of Outcomes in Adults with Nonalcoholic Fatty Liver Disease. New England Journal of Medicine, 385: 1159-1569. DOI: 10.1056/NEJMoa2029349
Sanyal, A.J., Shankar, S.S., Yates, K.P. et al (2023). . Diagnostic Performance of Circulating Biomarkers for Non-alcoholic Steatohepatitis. Nature Medicine 29, 2656–2664 (2023). https://doi.org/10.1038/s41591-023-02539-6
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