# National Institutes of Health funding for venous thromboembolism research

## TL;DR

This paper analyzes NIH funding for venous thromboembolism research over a decade, finding it remains low compared to other major vascular diseases.

## Contribution

The study provides the first descriptive analysis of NIH VTE research funding using a novel classification approach with a large language model.

## Key findings

- NIH VTE funding peaked at $73 million in 2021 but totaled $67.1 million in 2024.
- In 2023, VTE funding per death was significantly lower than for heart disease and stroke.
- 490 unique VTE grants were identified after excluding renewal awards.

## Abstract

Venous thromboembolism (VTE) is associated with approximately 100 000 deaths annually in the United States (U.S.). Progress in the prevention, diagnosis, treatment, and recovery from VTE depends on research funding. The National Institutes of Health (NIH), the world’s largest funder of biomedical research, does not currently report VTE-specific funding in its annual Categorical Spending Report.

This study aimed to provide a descriptive analysis of NIH funding for VTE research over the past decade.

We conducted a search of the NIH Research Portfolio Online Reporting Tools Expenditures and Results database from 2015 to 2024 using a string of VTE-related search terms. Grants were categorized as VTE research (yes/no) using a large language model prompted with predefined classification criteria. We tabulated annual NIH funding amounts, the number of VTE-related grants, and the number of unique principal investigators. For 2023, VTE research investment was compared with that for heart disease and stroke, the leading causes of vascular mortality in the U.S.

The search yielded 2130 grants with complete data, of which 1114 were classified as VTE research. When excluding renewal awards, 490 unique VTE grants were identified. Total inflation-adjusted NIH funding for VTE research was $42 million in 2015, peaked at $73 million in 2021, and totaled $67.1 million in 2024. In 2023, NIH funding per annual deaths was $2765 for heart disease, $2724 for stroke, and $639 for VTE.

NIH investment in VTE research has increased over the past decade, but remains disproportionately low relative to other major causes of vascular mortality in the U.S.