From 2006 to 2014 the National Institutes for Health (NIH) funded fewer trials, while industry-funded trials increased substantially. During that time period, the NIH’s budget decreased 14 percent after adjusting for inflation.

Lead researcher Stephan Ehrhardt, MD, MPH, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, and colleagues published their results online in JAMA on Dec. 15.

Since 2005, researchers have been required to register trials if they want them published in major medical journals. The FDA also requires registration of studies it defines as an applicable clinical trial that were initiated after Sept. 27, 2007 or initiated on or before that date and were still ongoing as of Dec. 26, 2007.

Ehrhardt and his colleagues downloaded data from ClinicalTrials.gov and searched for the term “interventional study” between 2006 and 2014. During those years, the number of newly registered trials based on the first received date increased from 9,321 to 18,400, while the number of industry-funded trials increased by 43 percent and the number of NIH-funded trials decreased by 24 percent.

In addition, the number of trials funded by other categories increased 227 percent. The “other” category includes individuals, Universities and organizations.

When the researchers used the study start date instead of the first received date, the number of newly registered trials increased 59 percent, the number of industry-funded trials increased 17 percent and the number of NIH-funded trials decreased 27 percent.

The researchers cited a few limitations of using ClinicalTrials.gov, including that there are differences in data based on registration date and study date and that investigators may define study start dates differently. They also mentioned that they may have underestimated the observed reduction in NIH-registered trials and that the “other” category includes numerous funders from outside the U.S.