Rare diseases are often chronically debilitating and sometimes life threatening. They each affect fewer than 200,000 people nationwide. Rare diseases may seem like a small corner of health care, but together, they affect nearly 10 percent of the US population. That’s about equal to the number of Americans diagnosed with diabetes. Yet most rare diseases are not studied enough. As a result, patients with rare diseases often face years of testing or ineffective treatments.

PCORI recognizes the special challenges that rare diseases, which often are understudied, pose. Learn more about our growing research portfolio.


Health Conditions Health Conditions These are the broad terms we use to categorize our funded research studies; specific diseases or conditions are included within the appropriate larger category. Note: not all of our funded projects focus on a single disease or condition; some touch on multiple diseases or conditions, research methods, or broader health system interventions. Such projects won’t be listed by a primary disease/condition and so won’t appear if you use this filter tool to find them. View Glossary
Populations Populations PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders. View Glossary
Resource Type

What's Happening at PCORI?

The Patient-Centered Outcomes Research Institute sends weekly emails about opportunities to apply for funding, newly funded research studies and engagement projects, results of our funded research, webinars, and other new information posted on our site.

Subscribe to PCORI Emails


Hand pointing to email icon