In this column, an endocrinologist discusses the growing problem of liver disease and new options at their disposal, including vibration-controlled transient elastography.
A growing number of endocrinologists, challenged with the nation’s liver disease epidemic, are seeking options to help them better assess liver health and manage and monitor patients with nonalcoholic fatty liver disease (NAFLD), a chronic health condition caused by excess deposition of fat in the liver.
NAFLD, which occurs commonly in people with obesity and its related conditions, such as type 2 diabetes, affects approximately 85 million Americans. It can broadly be categorized into nonalcoholic fatty liver (NAFL), a condition referred to as “simple” or “bland” steatosis, which consists almost solely of excess hepatic fat; and the more advanced form, nonalcoholic steatohepatitis (NASH), in which the excess hepatic steatosis is accompanied by inflammation, hepatocellular damage, and sometimes fibrosis.
Today, a definitive diagnosis of NASH and fibrosis can only be made with a liver biopsy. It is estimated that NASH affects approximately 30 million Americans, a number that is steadily growing with the ever-increasing prevalence of overweight and obesity.
From a clinical perspective it is important to note that, depending on patient characteristics, up to one-third of the NASH population will develop fibrosis, which can result in cirrhosis, liver failure, and increased risk of hepatocellular carcinoma. In fact, in the United States, NAFLD is currently the leading cause of liver transplantation in women and is estimated to soon overtake alcoholic liver disease as the overall leading cause of transplantation.1
Despite its high prevalence, most patients with NAFLD are asymptomatic and undiagnosed – leading to delayed identification of advancing liver disease, which can have significant human and economic costs. Given this, simple, non-invasive tools to help identify and risk-stratify patients with NAFLD are becoming increasingly important in the clinical care of patients with metabolic disorders, such as obesity and type 2 diabetes. One such method is vibration-controlled transient elastography (VCTE).
Vibration-Controlled Transient Elastography
Traditional methods for identifying NAFL, NASH and liver fibrosis are generally either complicated, expensive, and potentially invasive, such as liver biopsy. Also, they may not be adequately sensitive. VCTE is now available for clinicians to help assess liver fat content and stiffness, and has been shown to be a reliable, accurate, safe, and painless method to evaluate patients for NAFL and NASH. The exam can be office-based and performed by a trained operator, such as a nurse, physician, or technician, and typically takes 5-10 minutes. 2
VCTE provides a liver stiffness measurement (LSM), which is an estimate of hepatic fibrosis. Stiffness is calculated from the speed of the shear wave controlled and generated in the liver. A second measurement, controlled attenuation parameter (CAP), estimates hepatic steatosis.
Results are available immediately for interpretation by the health care professional. These tools produce several measurements for simplified and consistent interpretation, rather than images which often cannot be easily quantified. This enables clinicians to share results with the patient at point-of-care and to monitor changes in liver fat content and fibrosis over time.
CAPis a quantitative surrogate of liver steatosis expressed in decibel per meter (db/m). Most people with metabolic disorders, such as obesity and type 2 diabetes, have elevated CAP scores, because fatty liver disease (FLD) is very common in these patients. Sharing this objective measure of hepatic steatosis can be an important tool to help motivate lifestyle changes leading to reduction in body weight. Additionally, since key antidiabetic agents such as glucagon-like peptide 1 receptor agonists (GLP-1 RAs) and sodium glucose cotransporter 2 inhibitors (SGLT2) generally result in weight loss and improvements in hepatic steatosis, measures of hepatic fat may also help improve adherence with therapy. Since relative weight reduction of 5% to 7% is associated with a reduction in liver fat and inflammation, following the patient’s CAP score over time can be reassuring to clinicians and also motivational for patients.
The liver stiffness measure can be used to non-invasively identify patients at high risk of active fibrotic NASH from among those with high suspicion of NAFLD.3 Since the degree of hepatic fibrosis is an extremely important prognostic indicator, this information can be used by primary care physicians and non-hepatologist specialists, such as endocrinologists, to inform whether a referral should be made to a hepatologist, or if the patient can continue to be followed in the current setting and treated with lifestyle intervention and aggressive management of cardiovascular risk factors.
VCTE results and scores enable endocrinologists to make decisions in real time at the point of care. Armed with a reliable, early identification of patients with FLD, they can decide who should receive treatment, suggest proactive intervention and behavior change, including recommendations for diet and exercise, and also monitor how the patient is responding to therapy.
An independent assessment conducted by Santa Barbara Actuaries Inc. to evaluate from the payer’s perspective the cost effectiveness of deploying VCTE/CAPtechnology for detecting and monitoring FLD found that early identification of patients with FLD through broad placement of VCTE/CAP devices offers cost savings to payers. The model relied on administrative claims data consisting of 5 million commercial members and 3 million Medicare members to inform baseline statistics on disease prevalence, health care cost and utilization, and disease progression associated with different severities of liver disease. In fact, across a 5-year time span, researchers estimated net savings up to $2.64 per member per month (PMPM) for Medicare payers and up to $1.91 PMPM for commercial payers. The study concluded that deploying VCTE/CAP devices is a financially advantageous solution to address the FLD epidemic.
VCTE exams at the point of care are poised to play a key role in a comprehensive assessment of liver health. Combined with chronic care management strategies to address NAFLD, this approach optimizes a medication-free and highly effective way to halt or reverse liver damage. These tools are also expected to play a critical role in the detection and ongoing assessment of liver health to trigger prescriptions of medications for FLD—when these drugs become available—at the appropriate time.
1. Dokmak A, Lizaola-Mayo B, Trivedi HD. The impact of nonalcoholic fatty liver disease in primary care: A population health perspective. Am J Med. 2021;134(1):23-29. doi:10.1016/j.amjmed.2020.08.010
2. Younossi ZM et al; role of noninvasive tests in clinical gastroenterology practices to identify patients with nonalcoholic steatohepatitis at high risk of adverse outcomes: expert panel recommendations. Am J Gastroenterol. 2021;116(2):254-262. doi:10.14309/ajg.0000000000001054
3. Newsome PN, Sasso M, Deeks JJ, et al FibroScan-AST (FAST) score for the non-invasive identification of patients with non-alcoholic steatohepatitis with significant activity and fibrosis: a prospective derivation and global validation study. Lancet Gastroenterol Hepatol. 2020;5:362–373. doi: 10.1016/S2468-1253(19)30383-8
[viii] Newsome, Philip N. et al; FibroScan-AST (FAST) score for the non-invasive identification of patients with non-alcoholic steatohepatitis with significant activity and fibrosis: a prospective derivation and global validation study;The Lancet; April 1, 2020; FibroScan-AST (FAST) score for the non-invasive identification of patients with non-alcoholic steatohepatitis with significant activity and fibrosis: a prospective derivation and global validation study - The Lancet Gastroenterology & Hepatology; accessed January 4, 2022.
[ix] Noureddin, 2021.
[x] Noureddin, 2021.