Conference Coverage

Study eyed zinc for slowing progression of chronic liver disease


 

AT THE LIVER MEETING 2016

– Oral zinc supplementation was associated with maintenance of liver function and suppression of hepatocellular carcinoma in a retrospective cohort study of 267 patients with chronic liver disease.

Additional analyses revealed stepwise inverse relationships between serum zinc levels and rates of de novo liver failure, hepatocellular carcinoma, and death, Atsushi Hosui, MD, PhD, said at the annual meeting of the American Association for the Study of Liver Diseases. No patients stopped zinc therapy because of adverse events, and there were no serious adverse events, although some patients experienced nausea, which can occur with zinc supplementation, noted Dr. Hosui of Osaka-Rosai Hospital, Japan.

a bottle of zinc minerals is shown. ilkab/Thinkstock
Zinc is “pivotal” for the function of alkaline phosphatase and other enzymes that support liver function and for enzymes that neutralize reactive oxygen species, such as superoxide dismutase, Dr. Hosui said. In Japan, patients with low serum zinc levels are often supplemented with oral zinc sulfate capsules dosed at 30-60 mg daily, he added. Patients with liver disease often have low zinc levels, which continue to drop as liver disease progresses, he noted. In a previous study he helped conduct, average serum zinc levels were 85 mcg/dL in healthy controls, 63 mcg/dL in patients with chronic hepatitis, and 55 mcg/dL in patients with cirrhosis, he said.

To begin exploring hepatic correlates of zinc supplementation, Dr. Hosui and his associates retrospectively studied 267 patients in Japan with chronic liver diseases between 2006 and 2015. They had a median of 40 months of data for each patient. No patient had hepatocellular carcinoma at baseline. In all, 196 patients received zinc supplementation (average baseline zinc level, 51 mcg/dL), while 71 patients did not (62 mcg/dL). These two groups resembled each other in terms of etiologies of liver disease, but the zinc group was significantly older (73.2 vs. 66.4 years; P less than .0001), had a significantly higher average baseline bilirubin level (1.2 vs. 0.8 mg/dL; P less than .0001), and a significantly lower average platelet concentration and prothrombin time. (P less than .0001).

Despite having multiple indicators of worse liver disease, only 9.5% of zinc recipients developed hepatocellular carcinoma over 3 years, compared with 25% of patients in the control group (P = .005). Rates of liver failure and death were similar between the two groups, but sequential blood tests did indicate worsening liver disease among patients who did not receive zinc – their prothrombin times and branched-chain amino acid to tyrosine ratios steadily dropped over 3 years, while those in zinc recipients did not.

Next, the researchers stratified zinc recipients according to their serum zinc levels 6 months after starting supplementation. Notably, 3-year rates of mortality, liver failure, and death were significantly higher among patients whose zinc levels were lower than in patients who achieved higher serum zinc levels. For example, 3-year mortality rates were 28% among patients whose zinc level was 70-89 mcg/dL, versus 0% among patients whose zinc level was at least 90 mcg/dL (P = .02). Similarly, 3-year rates of liver failure were 3.6% among patients whose zinc level was 50-69 mcg/dL, versus 0% among patients whose serum zinc level was at least 70 mcg/dL (P = .03). Finally, over 3 years, hepatocellular carcinoma was diagnosed in 17% of patients whose zinc level was 50-69 mcg/dL, versus only 3.8% of patients whose zinc level was 70-89 mcg/dL.

“We suggest that oral zinc supplementation is effective for maintaining liver function and suppressing the development of hepatocellular carcinoma,” Dr. Hosui concluded. The data support a target serum zinc level of at least 70 mcg/dL to suppress liver-related events, including hepatocellular carcinoma, he added. The researchers are exploring clinical trials of zinc for these outcomes in Japan.

The investigators did not report funding for this study. They reported having no conflicts of interest.

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