Rare Daily Staff

A new effort to quantify the number of people with rare diseases using the French National Institute of Health and Medical Research’s (Inserm) Orphanet database, the largest collection of epidemiological data on these diseases taken from the scientific literature, estimates more than 300 million people worldwide are living with a rare disease.

Inserm said that the study, published in the European Journal of Human Genetics, is the first to analyze the available data on rare diseases with such precision. Nevertheless, it says the estimates are conservative. Created in 1997 by Inserm, Orphanet is a consortium of 40, mostly European countries that work together to pool within it the available data on rare diseases taken from the scientific literature. Inserm calls Orphanet the most comprehensive resource in the field.

The authors found that rare diseases affect at least 3.5 percent to 5.9 percent of the worldwide population. This point prevalence translates into what they characterized as conservative estimates of between 263 million to 446 million people living with rare disease worldwide. The U.S. Centers for Disease Control and Prevention estimates 400 million people worldwide live with a rare disease.

“In all likelihood, our data represent a low estimation of the reality. The majority of rare diseases are not traceable in healthcare systems and in many countries, there are no national registries,” said Ana Rath, director of Inserm US14 and an author on the paper. “Making patients visible within their respective healthcare systems by implementing means to record their precise diagnoses would make it possible in the future not only to review our estimations, but more fundamentally to improve the adaptation of support and reimbursement policies.”

The study did not include rare cancers, infectious diseases, and poisoning in its analysis and cautioned that the number of people affected by rare diseases is “likely considerably higher.”

The authors said that long-term population registries and the implementation of a specific codification for the identification of rare disease patients in healthcare systems would help refine the estimates. They say such figures are needed to identify priorities for health and research policy, understand the societal burden of these diseases, adapt the management of patients, and promote a real public health policy for rare conditions.

In the study, the team examined the data available on the point prevalence of 3,585 rare diseases.  They then added together the point prevalences of the various diseases referenced in the database to arrive at their estimate.

Among other findings, the researchers said that out of more than 6,000 diseases described in Orphanet, 72 percent are genetic and 70 percent start in childhood. Among the diseases analyzed in the study, 149 were responsible for 80 percent of cases of rare diseases identified worldwide.

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