Final Research Report

View this project's final research report.

Peer-Review Summary

Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.

The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments. 

Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following:

  • The reviewers expressed concern that the study might have excluded people with more severe forms of bipolar disorder. The researchers responded that their only restriction on participants was that they had spent at least one year in a low-deductible health plan followed by at least one year in a high-deductible health plan that an employer had mandated. The researchers said these criteria captured people with all severity levels of bipolar disorder. They illustrated this statement by showing that among the patients included, 29 to 30 percent had emergency department visits and 13 to14 percent had hospitalizations in the baseline year.
  • The reviewers wondered if the relatively minor consequences observed in this study of switching to high-deductible plans would be true for people with very high deductibles. The researchers agreed that patients with very high deductibles are an important group to study but said such deductible levels are not common, so results of such an analysis would not be generalizable. The researchers noted that only 5 percent of patients in their study had deductibles of $2500 or higher. They added comments to the report stating that the small number of patients with very high deductibles precluded their ability to analyze results separately for this group. The researchers commented that as rates of high-deductible plans rise, future research should focus on this question.
  • The reviewers similarly wondered if the results were generally equivocal because the difference between low-deductible plans and high-deductible plans could be as little as $500, which might not be enough of a difference to change patients’ treatment behavior. The researchers pointed out that $500 would be the minimum difference in deductibles so the average difference was much higher. However, the researchers also noted that they did not have a sufficient sample with very high deductibles to be able to compare treatment behaviors in just this subgroup to the low-deductible group.
  • The reviewers noted that the one-year follow-up for the study was too short to fully assess the consequences of reduced use of preventative care. In particular, the reviewers noted that the substantial decrease in non-psychiatric medical visits was worrying and wondered if differences in health outcomes would emerge over time. The researchers agreed that differences in measures like emergency department visits and hospitalizations could emerge over time and said their study design could examine such outcomes. However, they said much larger sample sizes would be needed, e.g., 100,000 people, compared with the fewer than 6500 people in their study, to assess differences in long-term adverse events such as heart attacks and strokes.
  • The reviewers asked why the study included adolescents over age 12, since the bipolar diagnosis is not stable in adolescents, there is little evidence that interventions used in adults benefit children and adolescents, and adolescents do not pay for their own health care. The researchers replied that any measurement error resulting from including children and adolescents would be the same across study groups and therefore, not a source of bias. They also stated that changing to a high-deductible plan would still affect these young people’s ability to access care, even if the change in insurance coverage was due to caregiver rather than patient actions.

Conflict of Interest Disclosures

Project Information

James Franklin Wharam, MB, BCh, BAO, MPH
Harvard Pilgrim Health Care, Inc.
Impact of High Deductible Health Plans on Patients with Bipolar Disorder

Key Dates

April 2015
June 2020

Study Registration Information


Has Results
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
Funding Opportunity Type
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: March 4, 2022