Liver Disease Disparities Rarely Studied in Europe, Review Finds

A new analysis found only 1 in 10 studies of inequities in liver cancer had a European focus or origin.

Despite the high prevalence of hepatocellular carcinoma (HCC), nonalcoholic fatty liver disease (NAFLD), and other liver disorders in Europe, relatively little scientific research has focused on disparities in the rates and outcomes of liver disease among various populations, according to a new report.

In an article in the Journal of Hepatology, corresponding Juan M. Pericàs, MD, PhD, MPH, of the Vall d’Hebron Institute of Research, in Spain, and colleagues, argued that more attention should be paid to health care disparities in liver disease in Europe. They say better research could enable a more targeted focus by clinicians and academics on the social determinants underlying those disparities.

Pericàs and colleagues said inequality is an important topic in liver disease because social factors can impact both a person’s developing disease, and the person’s ability to access proper care once they have the disease. For example, previous research has suggested that people with low educational levels or who are from socioeconomically deprived areas have higher rates of cirrhosis mortality. Research in the United States has also suggested that men with cirrhosis are more likely than women with cirrhosis to receive liver transplants, and that 1-year survival following liver transplants varies by racial and ethnic group.

“The impact of inequality on liver disease is not a direct one but rather the interaction of multiple factors that might act synergistically and have delayed and multilayered effects on how liver disease is distributed across populations and how it affects more severely some groups and individuals than others,” the investigators wrote.

Yet, most of the data surrounding disparities in liver disease prevalence and outcomes is based either on studies of populations outside of Europe, or was conducted by institutions outside of Europe, Pericàs and colleagues found.

They performed a literature search seeking articles examining health inequalities and disparities in liver disease that were published between 1966 and June 7, 2022. They initially identified 474 studies, but after excluding duplicates and out-of-scope studies, were left with a total of 303 studies.

The investigators reported a number of “striking” findings. They found no studies before the 2000s, and most of the studies they found were from the past 5 years. Most of the studies, they said, took a “reductionist approach” and only dealt with simple quantitative differences.

The geography of the research was also notable, Pericàs and colleagues said. All but 16.1% of the studies were carried out by institutions in the United States. Just 10.2% of the studies identified were led by European institutions or examined populations in Europe.

When the investigators analyzed the existing literature by disease category, they found studies about liver transplants were most common. However, most of those studies were about the United States, and most focused on how prioritization rules and scores affected wait times and outcomes for different populations.

“In short, although many studies have investigated the frequency and impact of inequalities on liver transplantation, this is likely the clearest example of a topic that has been largely addressed from a ‘disparities’ perspective, where the mechanisms of inequalities have been often overlooked,” they wrote.

The authors cited a number of potential reasons that inequalities in liver disease in Europe have not been extensively studied. They said it could have to do with a lack of available educational courses and programs in Europe that emphasize health inequalities. In addition, they said people might overlook potential disparities in healthcare access since most European countries have universal healthcare programs.

Pericàs and colleagues said researchers and practitioners can curb the problem, but only if they take an active role. The solution will need to include more comprehensive data gathering and analysis, as well as a commitment to interventions based on those data and disparities.

“To achieve this goal, Europe should increase its awareness of health inequalities in the liver arena, perform high quality research and guide and inspire the health policy-makers and society as a whole to close this gap so all our communities are protected and effectively protected from liver diseases,” they concluded.

Reference

Ventura-Cots M, Bataller R, Lazarus JV, Benach J, Pericàs JM. Applying an equity lens to liver health and research in Europe. J Hepatol. Published online August 16, 2022. doi:10.1016/j.jhep.2022.07.021