Project Summary

This research project is in progress. PCORI will post the research findings on this page within 90 days after the results are final.

What is the research about?

Asthma is a long-term health problem that affects 6.8 million children and 18.7 million adults in the United States. Patients can take medicine to control their asthma. But many patients don’t take their medicine every day. One reason may be that patients have trouble paying for it.

Insurance plans help patients pay for health care and medicine. In regular insurance plans, patients spend some of their own money, called out-of-pocket costs, before insurance pays. For example, patients may need to spend $500 on healthcare services or medicine before the insurance plan starts to pay for their health care.

Many employers are now changing their insurance plans for employees to high-deductible health plans, or HDHPs. In an HDHP, patients or families pay a smaller amount each month to have insurance but must pay higher out-of-pocket costs, such as $1,000 to $2,000, before insurance begins to cover their healthcare costs. Patients with high out-of-pocket costs sometimes choose not to buy the medicine they need. But some insurance plans have a list of medicines that are free to patients and families because they help prevent health problems. Asthma medicine is usually on this list.

In this study, the research team is comparing whether switching from regular insurance to an HDHP changes how often people use asthma medicine or go to the hospital because of asthma. The team also wants to know whether these results differ if the HDHP includes a list of free medicines, including asthma medicine.  

Who can this research help?

Employers can use results of this study when considering types of insurance to offer to their employees. Patients with long-term health problems can use results when considering what types of insurance to choose.

What is the research team doing?

The research team is using health insurance data from more than 2 million patients with asthma who have insurance through their employers. The team is looking at patients who switch from a regular insurance plan to an HDHP. The research team is also comparing HDHPs that have lists of free medicine with those that don’t. For each type of insurance, the team is comparing asthma medicine use, visits to the emergency room, and hospital stays for asthma-related causes. In addition, the team is comparing the amount of money patients spend on healthcare costs before and after switching insurance plans.

Adults with asthma and parents of children with asthma are working with the research team to plan and conduct the study.

Research methods at a glance

Design Elements Description
Design Observational: cohort study
Population Adults and children with asthma enrolled in an employer-sponsored health plan from a large national insurance carrier for 24 months continuous from 2004 to 2017
  • HDHP with a PDL (annual deductible > $1,000)
  • ​HDHP without a PDL (annual deductible > $1,000)
  • Regular plan (annual deductible <$1,000)

Primary: proportion of days covered, medicine discontinuation rate, use of asthma rescue medicine, asthma-related ER visits and hospital stays, out-of-pocket costs

Timeframe At least 1-year follow-up for primary outcomes

Project Information

Alison Amidei Galbraith, MD, MPH
Harvard Pilgrim Health Care, Inc.
Comparing Patient-Centered Outcomes for Adults and Children with Asthma in High-Deductible Health Plans with and without Preventive Drug Lists

Key Dates

December 2016
January 2023

Study Registration Information


Award Type
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
Intervention Strategy Intervention Strategies PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care. View Glossary
Research Priority Area
State State The state where the project originates, or where the primary institution or organization is located. View Glossary
Last updated: January 20, 2023