CHICAGO — A noninvasive breath test that measures exhaled 13C-methacetin can accurately predict the risk of liver decompensation within up to 2 years.
With more confirmatory research, the test “could be used to give transplant priority to patients who are at risk of imminent decompensation, or to determine whether a cirrhotic patient has enough liver reserve to undergo a hepatic resection or other surgery,” Dr. Gadi Lalazar said at a press briefing at the annual Digestive Disease Week.
Currently, the Model for End-Stage Liver Disease (MELD) and Child-Pugh scores are the best ways to evaluate hepatic reserve in patients with chronic liver disease, said Dr. Lalazar of Hebrew University-Hadassah Medical Center, Jerusalem. But the scoring systems aren't foolproof. “MELD's main predictive power is only for up to 90 days, and we often see patients with similar MELD scores and very different disease courses—some will decompensate and die and some will not.”
The breath test is administered with a portable machine (Breath ID, manufactured by Exalenz Bioscience Ltd.). Patients fast for 8 hours before the test, then drink 150 mL of water containing 75 mg of methacetin. They wear a nasal cannula while hooked to the machine, which continuously collects and analyzes their breath for 60 minutes.
Methacetin is metabolized solely by healthy hepatocytes, Dr. Lalazar said. He described the process in a paper published earlier this year (World J. Gastro. 2009;15:966-72).
Preliminary studies found that the test reliably distinguished between early cirrhotic and noncirrhotic patients with 95% sensitivity and 97% specificity.
Dr. Lalazar and his colleagues examined the test's ability to predict death from liver failure over a 2-year period in a cohort of 575 patients with chronic liver disease. The patients' mean age was 48 years; 209 of them had cirrhosis. The mean MELD score at baseline was 9. Most of the group (67%) had hepatitis C infection. Patients were divided into risk groups according to their breath test results: low risk (342 patients), moderate risk (135), and high risk (98).
There were 25 deaths in the entire cohort over the 2-year follow-up period. When analyzed by the breath test risk levels, most of the deaths occurred in the high-risk group (15% of that group). Deaths occurred in 6% of the moderate-risk group and in 1% of the low-risk group. The relationship of death to risk group was consistent at every time point in the study. (See chart.)
The investigators then examined the rate of death in the subgroup of cirrhotic patients. The breath test identified 42 patients as low risk, 83 patients as moderate risk, and 84 as having a high risk. At 2 years, there was 1 death in the low-risk group, 7 in the moderate-risk group, and 14 in the high-risk group.
The machine is now being analyzed in a phase III U.S. trial for the detection of cirrhosis in patients with chronic liver disease (clinicaltrials.govNCT00736840
Dr. Lalazar said he had no financial interest in the company or any other potential conflict regarding the study.
Source ELSEVIER GLOBAL MEDICAL NEWS