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A new analysis of mortality and morbidity highlights a growing issue with counting hepatitis C virus-related deaths as they are largely underreported.¹

A team, led by Frédérique Hovaguimian, PhD, Division of Infectious Diseases and Hospital Epidemiology, University Hospital of Zurich, University of Zurich, identified electronic health records of patients with HCV infections and assessed mortality and morbidity within this patient population.

HCV Mortality Issues

It can be very difficult to obtain true estimates on HCV mortality and studies focusing on comparing deaths from national registries with fatal events in national cohorts have largely found that HCV-related mortality is underreported. The studies may not be representative of some of the populations disproportionally affected by HCV, including sexual minorities or people who inject drugs.

“To tackle this major public health issue, the World Health Organization (WHO) issued an elimination strategy in 2016, with the goal to reduce hepatitis-related mortality by 65% until 2030,” the authors wrote. “The exact burden related to HCV, however, remains difficult to assess.”

A Need for New Approaches

New approaches to better focus on morbidity and mortality estimates within this patient population are badly needed.

“The solution may lie in searching electronic health records, which capture routinely collected data from large populations,” the authors wrote. “With this approach, search strategies described as electronic phenotyping are used to query electronic health records, with the aim to identify patients with specific characteristics.”

In the study, the investigators applied electronic phenotyping strategies on routinely collected data from patients hospitalized at a tertiary referral hospital in Switzerland between 2009-2017. Outpatient visits were not included in the study.

The team identified patients with HCV using International Classification of Disease (ICD)-10 codes, prescribed medications, and laboratory results (antibody, PCR, antigen or genotype test).

They also added a control group to the study using propensity score methods matched by age, sex, intravenous drug use, alcohol abuse, and HIV co-infection.

The investigators sought main outcomes of in-hospital mortality and attributable mortality in both patients with HCV and the control group.

The non-matched dataset included data on 165,972 patients involving 287,255 hospital stays.

Results

The investigators identified 2285 stays with evidence of an HCV infection from 1677 patients using electronic phenotyping.

The propensity score matching resulted in 6855 hospital stays, 2285 from patients with HCV and 4570 from the control group.

The results show in-hospital mortality was higher for patients with HCV (risk ratio (RR), 2.10; 95% confidence interval, 1.64-2.70).

For individuals with HCV, 52.5% of deaths were deemed attributable to the infection (95% CI, 38.9-63.1).

After matching the cases, the investigators found 26.9% of deaths were attributable to HCV (HCV prevalence: 33%).

However, this dropped to 0.92% in the non-matched dataset (HCV prevalence: 0.8%).

“In this study, HCV infection was strongly associated with increased mortality,” the authors wrote. “Our methodology may be used to monitor the efforts towards meeting the WHO elimination targets and underline the importance of electronic cohorts as a basis for national longitudinal surveillance.”