Reported cases of acute hepatitis C just the tip of the iceberg, study suggests

Last Updated: 2015-07-01

By Megan Brooks

NEW YORK (Reuters Health) - The current U.S. public health surveillance system may grossly underestimate the number of acute hepatitis C virus (HCV) infections, according to new data from Massachusetts.

"Estimates of the incidence of acute HCV infection are complicated by the lack of a specific laboratory test and its generally asymptomatic presentation," researchers note in a report online June 30 in Annals of Internal Medicine.

They reviewed the medical records of 183 patients clinically diagnosed with acute HCV infection at two hospitals and the state correctional health care system in Massachusetts from 2001 and 2011.

Altogether, 149 of those cases (81.4%) were reported to the Massachusetts Department of Public Health (MDPH) for surveillance classification.

"The MDPH investigated 43 of these reports as potential acute cases of HCV infection based on their surveillance requirements; ultimately, only 1 met the national case definition and was counted in nationwide statistics published by the Centers for Disease Control and Prevention," the researchers report.

"Discordance in clinical and surveillance classification was often related to missing clinical or laboratory data at the MDPH as well as restrictive definitions, including requirements for negative hepatitis A and B laboratory results," they note.

Dr. Arthur Kim from Massachusetts General Hospital in Boston, the senior author of the report, said hepatitis C can be likened to an iceberg where only the tip is visible to clinicians, "let alone downstream public health authorities."

"And so the absolute size of the iceberg remains unclear, but is likely greater than we have previously appreciated and this is driven by an expanding opioid epidemic where many individuals transition to injection behaviors," he told Reuters Health.

Not having accurate estimates of acute HCV infection "makes it hard to plan for the future," Dr. Kim said. "Ultimately, many of these individuals will require treatment, which will be very expensive down the line."

"One of the implications of our study -- other than trying to get much better data as to how many people are truly acquiring this infection -- is to focus more on prevention because an ounce of prevention is worth in this case tens of thousands of dollars in cure," Dr. Kim noted.

The researchers call for a reexamination of the methods used for measuring the burden of HCV in the U.S.

Dr. Kim told Reuters Health, "Since 2011, the CDC has done several things to improve the possibility that they can see more acute cases, and CDC along with their partners are already experiencing an increase in acute reported cases."

Dr. John Ward, director of the Division of Viral Hepatitis at CDC, told Reuters Health by email, "CDC has long recognized that most acute hepatitis C cases are not reported to CDC as a result of limited hepatitis C testing by providers and limited capacity of health departments to capture diagnosed cases. To get a better understanding of the issue, CDC recently revised the calculations used to quantify the number of estimated new cases of hepatitis C based on the actual number of cases reported. This new methodology . . . indicates that 30,000 or more acute hepatitis C cases occur each year," said Dr. Ward, who wasn't involved in the Massachusetts study.

The study was supported by grants from the National Institutes of Health and the CDC. The authors reported no disclosures.

SOURCE: http://bit.ly/1U5cWRi

Ann Intern Med 2015.