Growth of the hepatitis literature over the period 1976–2015: What can the relative priority index teach us?

Abstract

This study has a double purpose: a fact-finding one and a methodological one. The fact-finding part consists of two elements. First we study the growth of the hepatitis literature in the World and in particular in India over the latest 30 years (1986–2015). Second we determine the priority given to hepatitis studies in a number of leading countries, distributed over five continents. This part compares the periods (1976–1995) and (1996–2015). The methodological part studies the stability of the relative priority or activity index by calculating it with respect to different databases. Data are collected from PubMed, the Web of Science (WoS) and the WoS, restricted to the area Life Sciences Biomedicine, denoted as WoS (LS). Data collection in PubMed is more difficult than in the WoS, leading to possibly approximate results. Attention spent to publishing hepatitis research is measured with the Relative Priority Index (RPI). Initially the rise in the number of Indian publications is slow. Yet, the number of publications on hepatitis has substantially increased over time so that since 2008 India’s cumulative number of publications has more than doubled. As to the methodological problem we found that different databases lead to different results, showing that results based on the RPI must be interpreted with care. We, moreover, draw the reader’s attention to hepatitis itself, including information about it and its deadly consequences.

Appendices

Appendix A: Short descriptions of the five forms of viral hepatitis, taken from the Fact Sheets of the WHO

Hepatitis A

• Hepatitis A is a viral liver disease that can cause mild to severe illness.

• The hepatitis A virus (HAV) is transmitted through ingestion of contaminated food and water or through direct contact with an infectious person.

• Almost everyone recovers fully from hepatitis A with a lifelong immunity. However, a very small proportion of people infected with hepatitis A could die from fulminant hepatitis.

• The risk of hepatitis A infection is associated with a lack of safe water, and poor sanitation and hygiene (such as dirty hands).

• Epidemics can be explosive and cause substantial economic loss.

• A safe and effective vaccine is available to prevent hepatitis A.

• Safe water supply, food safety, improved sanitation, hand washing and the hepatitis A vaccine are the most effective ways to combat the disease.

Hepatitis B

• Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic disease.

• The virus is transmitted through contact with the blood or other body fluids of an infected person.

• An estimated 257 million people are living with hepatitis B virus infection (defined as hepatitis B surface antigen positive).

• In 2015, hepatitis B resulted in 887,000 deaths, mostly from complications (including cirrhosis and hepatocellular carcinoma).

• Hepatitis B is an important occupational hazard for health workers.

• However, it can be prevented by a currently available safe and effective vaccine.

Hepatitis C

• Hepatitis C is a liver disease caused by the hepatitis C virus: the virus can cause both acute and chronic hepatitis, ranging in severity from a mild illness lasting a few weeks to a serious, lifelong illness.

• The hepatitis C virus is a blood borne virus and the most common modes of infection are through exposure to small quantities of blood. This may happen through injection drug use, unsafe injection practices, unsafe health care, and the transfusion of unscreened blood and blood products.

• Globally, an estimated 71 million people have chronic hepatitis C infection.

• A significant number of those who are chronically infected will develop cirrhosis or liver cancer.

• Approximately 399,000 people die each year from hepatitis C, mostly from cirrhosis and hepatocellular carcinoma.

• Antiviral medicines can cure more than 95% of persons with hepatitis C infection, thereby reducing the risk of death from liver cancer and cirrhosis, but access to diagnosis and treatment is low.

• There is currently no vaccine for hepatitis C

Hepatitis D

• Hepatitis D virus (HDV) is a ribonucleic acid (RNA) virus that requires hepatitis B virus (HBV) for its replication. HDV infection occurs only simultaneously or as superinfection with HBV.

• The virus is transmitted through contact with the blood or other body fluids of an infected person.

• Approximately 15 million people across the World are chronically co-infected with HDV and HBV.

• Currently there is no effective antiviral treatment for hepatitis D.

• Hepatitis D infection can be prevented by hepatitis B immunization

Hepatitis E

• Hepatitis E is a liver disease caused by infection with a virus known as hepatitis E virus (HEV).

• Every year, there are an estimated 20 million HEV infections Worldwide, leading to an estimated 3.3 million symptomatic cases of hepatitis E, and 56,600 hepatitis E related deaths.

• Hepatitis E is usually self-limiting but some cases may develop into fulminant hepatitis (acute liver failure).

• The virus is transmitted via the faecal-oral route, principally via contaminated water.

• Hepatitis E is found Worldwide, but the prevalence is highest in East and South Asia.

• A vaccine to prevent hepatitis E virus infection has been developed and is licensed in China, but is not yet available elsewhere.

Appendix B: Retrieval problems in PubMed

We include these examples as warnings as well as suggestions for (partial) solutions.

Problem 1. American records that do not show the words US, USA or United States in the address field (Author information).

An example:

STEP Perspect. 1995 Summer; 7(2):13–15.

Liver function and HIV-1 infection.

Hernandez V.

Author information: Direct AIDS Alternative Information Resources, New York, NY.

We checked that if, indeed, this record cannot be retrieved with an American affiliation:

Search (((((“1976/01/01”[Date - Publication]: “1995/12/31”[Date - Publication])) AND hepatitis[Title/Abstract])) AND Hernandez V[Author]) AND (USA [Affiliation] OR US[Affiliation]).

This search yields no records.

A partial solution

The term “America” occurred sometimes in the name of an institution that otherwise only provided state information. So, by adding “America” in the search we retrieved quite some records that had no USA country name. An example is the following record.

J Perinat Educ. 2005 Winter; 14(1):46–49.

Toward more evidence-based practice.

Hotelling BA.

Author information: BARBARA HOTELLING is an independent childbirth educator and doula in Rochester Hills, Michigan. She has served as president of Lamaze International, president of Doulas of North America (DONA), and chair of the Coalition for Improving Maternity Services (CIMS).

Similarly, this happened with the term US. By adding US in the search we retrieved records that had no USA country name, and not “America’ in the affiliation field. An example is the following record.

Annu Rev Public Health. 1988; 9:203–221.

Viral vaccines and antivirals: current use and future prospects.

Parkman PD., Hopps HE.

Author information: Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, Maryland 20892.

However, this may have led to new errors, such as in the following record, which is not an American contribution (in our sense). Yet, we decided that the gain (correct unique records) resulting from including US in the query surpassed the loss (adding incorrect records). An example:

Trans R Soc Trop Med Hyg. 1994 Jan–Feb; 88(1):57.

Hepatitis E virus in Indonesia.

Jennings GB., Lubis I., Listiyaningsih E., Burans JP., Hyams KC.

Author information: US Naval Medical Research Unit No. 2, Jakarta, Indonesia.

Problem 2. Country names occurring in the address field of another country.

An example: Because of the local address of the institution (which includes US) this record is counted for the USA, but it is also counted for China.

IEEE Trans Neural Netw. 1992; 3(3):423–433.

The Mod 2 Neurocomputer system design.

Mumford ML., Andes DK., Kern LL.

Author information: US Naval Weapons Center, China Lake, CA.

Problem 3. China in PubMed

We searched for China OR Beijing (the capital city was included in order to retrieve articles with no country affiliation). This is set A.

Next we searched for “Republic of China”. The resulting set is set B. Most of these must be removed from the original search, except those that have “People’s Republic of China” in the affiliation field (set C). The required set of publications is those included in A\ (B\C). This is illustrated in Fig. 3.

Fig. 3

Illustration of the methodology to obtain China’s contributions in PubMed

Appendix C: Search for Life Sciences Biomedicine

SU = (Agriculture OR Allergy OR Anatomy & Morphology OR Anesthesiology OR Anthropology OR Behavioral Sciences OR Biochemistry & Molecular Biology OR Biodiversity & Conservation OR Biophysics OR Biotechnology & Applied Microbiology OR Cardiovascular System & Cardiology OR Cell Biology OR Critical Care Medicine OR Dentistry, Oral Surgery & Medicine OR Dermatology OR Developmental Biology OR Emergency Medicine OR Endocrinology & Metabolism OR Entomology OR Environmental Sciences & Ecology OR Evolutionary Biology OR Forestry OR Gastroenterology & Hepatology OR General & Internal Medicine OR Genetics & Heredity OR Geriatrics & Gerontology OR Health Care Sciences & Services OR Hematology OR Immunology OR Infectious Diseases OR Integrative & Complementary Medicine OR Legal Medicine OR Life Sciences Biomedicine Other Topics OR Marine & Freshwater Biology OR Mathematical & Computational Biology OR Medical Ethics OR Medical Informatics OR Medical Laboratory Technology OR Microbiology OR Mycology OR Neurosciences & Neurology OR Nursing OR Nutrition & Dietetics OR Obstetrics & Gynecology OR Oncology OR Ophthalmology OR Orthopedics OR Otorhinolaryngology OR Paleontology OR Parasitology OR Pathology OR Pediatrics OR Pharmacology & Pharmacy OR Physiology OR Plant Sciences OR Psychiatry OR Public, Environmental & Occupational Health OR Radiology, Nuclear Medicine & Medical Imaging OR Rehabilitation OR Reproductive Biology OR Research & Experimental Medicine OR Respiratory System OR Rheumatology OR Sport Sciences OR Substance Abuse OR Surgery OR Toxicology OR Transplantation OR Tropical Medicine OR Urology & Nephrology OR Veterinary Sciences OR Virology OR Zoology).