Rare Diseases

PCORI uses the Orphan Drug Act definition of a rare disease: a condition that affects fewer than 200,000 people in the United States. Although each disease is rare individually, it is estimated that more than 10,000 rare diseases affect about 30 million people in the United States and that 80 percent of rare diseases are genetic in origin. Through its funding of comparative clinical effectiveness research (CER) studies and related projects on rare diseases, PCORI is providing evidence to fill important rare disease research gaps.View PCORI's Rare Disease Portfolio

Rare Disease Study Spotlights

Effects of Oxygen Treatments on Patients with Pulmonary Fibrosis

Many doctors prescribe supplemental oxygen for patients with PF. The oxygen equipment can be hard to handle, making it difficult for people to leave the house. Little research has been done on whether oxygen treatment is helpful. This project compared the breathing and physical activity of patients given supplemental oxygen to that of those who were not to determine benefits and downsides. Researchers found that while patients with supplemental oxygen reported improvement in their symptoms, they felt frustrated with the equipment and judged in public.

Improving Discussions on Treatment Options for Lupus Nephritis

Jasvinder Singh, MD, MPH, at the University of Alabama at Birmingham, developed a decision aid under a PCORI-funded research award to help African-American and Hispanic patients have quality discussions with their clinicians regarding treatment options for lupus nephritis, a rare disease that affects young women. His team is now working to expand the decision aid’s use in clinical practice with a PCORI dissemination and implementation award.

Comparing Patient-Centered Outcomes in the Management of Pain for Adults with Sickle Cell Disease

A common complication of sickle cell disease is a constriction of blood vessels, which causes severe pain. Patients often report that their pain relief is insufficient and doctors don’t involve them in treatment decisions. This study is comparing whether care delivered in an infusion center staffed by expert clinicians is more effective for treating and managing pain than care delivered in an emergency department.

PCORI Funding Announcements Related to Rare Diseases

Addressing Health Outcomes for Individuals With Intellectual and Developmental Disabilities and/or Rare Diseases

Opens for LOI Submissions: Aug. 4, 2026

Putting Evidence Into Action

Composite Image: A female toddle lies in bed looking sad at an unidentifiable person standing next to her. A male toddler lying in bed holds his head in pain as another person holds a thermometer.

Treating Resistant Kawasaki Disease (Evidence Updates) 
Kawasaki disease (KD) is a rare disease that most commonly affects children. KD can be treated, but some children have resistant KD and do not respond to initial treatment. A PCORI-funded study compared the safety and effectiveness of two treatments for resistant KD. This study is the largest clinical trial to date on treatment for resistant KD. A pair of Evidence Updates provides information about second treatment options for children with KD whose fever doesn’t go away after their first treatment, and to help inform clinicians and parents as they make treatment decisions.

More Patient-Centered CER

Treating Pain in Adults with Sickle Cell Disease
Findings from a PCORI-funded study published in the Annals of Internal Medicine show promise for improving care of individuals living with sickle cell disease (SCD) in the United States. Researchers compared treatment for patients with uncomplicated vaso-occlusive crisis (VOC) in emergency rooms (ERs) and infusion centers. VOC is the most prevalent SCD complication and causes acute, excruciating pain that most commonly is treated in ERs. Patients receiving care in infusion centers reported waiting less time for pain medicine than ER patients. They also were more likely to receive care adhering to guidelines for the management of acute pain and less likely to be admitted to the hospital.

Resources for Rare Disease Research

PCORI Rare Disease Care Continuum Framework | Individual and Family Impacts: Caregiving, Complications, Comorbidities, Economic, Mental Health, Palliative Care, Quality of Life, Self-Care, Symptom Management | System Impacts: Access Issues, Appropriate Care, Clinical Trials, Care Coordination, Community and/or School Supports, Economic, Patient and Clinical Education, Neighborhood and Built Environment, Transitions of Care

Rare Disease Care Continuum Framework
The Rare Disease Care Continuum Framework is a resource for applicants and awardees responding to PCORI’s funding opportunities focused on rare diseases. The framework, which PCORI developed in consultation with the PCORI Rare Disease Advisory Panel, incorporates evidence gaps identified in the literature and those emphasized by patients, researchers, clinicians and other stakeholder groups.

PCORI Horizon Scanning Database: Icons for Alzheimer's Disease and other dementias, cancer, cardiovascular diseases, infectious diseases, mental and behavioral health, rare diseases, and other health conditions.

Database Identifies Emerging Technologies, Innovations
PCORI’s Horizon Scanning Database offers healthcare decision makers findings about advancements in six key areas of interest: Alzheimer’s disease and other dementias, cancer, cardiovascular diseases, infectious diseases, mental and behavioral health, and rare diseases. This database can be used by patients, care partners, and others to track advancements in care options.

PCORI's Rare Disease Portfolio

View additional PCORI-funded research studies & related projects on rare rare diseases.

View Rare Disease Portfolio