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Human Subjects Research

NIDDK funds human subjects research through various funding mechanisms. Before you apply to a notice of funding opportunity (NOFO), take the following steps.

  • NIDDK strongly recommends that you contact the Program Director responsible for your area of research before you submit an application. We recommend this contact occur at least 12 weeks prior to any planned submission.
  • Determine if your research is appropriate for NIDDK or another NIH Institute or Center. Prospective applicants may find the RePORTer matchmaker tool useful.
  • Determine if your research involves human subjects with the help of NIH’s Am I Doing Human Subjects Decision Tool or Private Information or Biological Specimens Decision Chart (PDF, 26 KB) , or your Institutional Review Board or Independent Ethics Committee. Your research may involve human subjects even if you are not working directly with human participants.
  • Determine if your research is a clinical trial. The NIH definition of a clinical trial encompasses therapeutic clinical trials and mechanistic trials.

    • Therapeutic trials determine clinical safety, tolerability, efficacy, and/or effectiveness of an intervention that is designed to prevent or treat a disease or condition.
    • Mechanistic trials—including physiologic studies or basic behavioral and experimental studies—understand a biologic process, the pathophysiology of a disease, or the mechanism of action of an intervention.
  • Select an appropriate NOFO and read it carefully. Many NOFOs have unique requirements and will specify whether applications involving clinical trials are allowed.
    • If your proposed clinical trial falls within the research areas and mission of NIDDK, you may be able to submit your application to PA-20-183 (for therapeutic and mechanistic clinical trials) or PA-20-184 (for basic experimental studies with humans).
  • NIDDK places a high priority on supporting studies that foster equity in research to inform the study design, research conduct, and applicability of research findings for the population(s) of interest. Applicants are encouraged to consider research activities that:
    • include interdisciplinary research teams comprised of individuals with a breadth of relevant lived experiences and scientific expertise.
    • include early and meaningful engagement with trusted organizations of health information and affected individuals as collaborators to ensure alignment of the research design (i.e., questions, approaches) with the values, preferences, and health priorities of those affected by the disease(s) being studied.  
    • conduct culturally relevant outreach, recruitment and retention strategies with diverse research participants who reflect the U.S. population with the disease(s) being studied or those who are affected but have been underrepresented in previous research.
    For additional information about NIDDK’s research priorities, read Pathways to Health for All: Health Disparities and Health Equity Research Recommendations and Opportunities, Appendix G (see page 63).

If you are applying for or have already received a clinical research grant you must follow both NIH and NIDDK policies for clinical research. Some NIH policies to keep in mind include:

You can also review the wide range of NIDDK Research Resources to help clinical researchers work more efficiently, lower costs, and improve effectiveness.

Funding Mechanisms for Human Subjects Research

Pilot & Feasibility Clinical Studies (Small R01s)

NIDDK supports small R01s for pilot and feasibility clinical trials within the mission of NIDDK through PAS-23-086. Applications to this Notice of Funding Opportunity are limited to three years and $200,000 in direct costs per year. Proposed studies should be designed to acquire preliminary data regarding the effects of the intervention, as well as feasibility data related to recruitment and retention, and study conduct. Preliminary data regarding intervention efficacy are not required.

Clinical Research Considered Low-Risk (R01)

For clinical studies that involve only one center, or involve low-risk studies at more than one center, R01s may be used. A single clinical research center may encompass one or more physical locations where the clinical trial is being conducted—i.e., where study participants are recruited, intervened upon, or have outcomes assessed under a single protocol—as long as all locations are under the overall direction of a single investigator. A multi-center study is classified as “high risk” if it utilizes either a high-risk intervention and/or invasive measures or has high operational risk, or both. Please review NOT-DK-20-051 for additional information on what is considered a low-risk versus a high-risk study.

Low-risk clinical trials within the mission of NIDDK may use the parent NIH NOFOs for clinical trials (PA-20-183 or PA-20-184 , as described above or other appropriate NOFOs from NIDDK.

Low-risk observational studies or other types of human subjects research that is not a clinical trial may use the PA-20-185 or specific NOFOs from NIDDK.

High-Risk Multi-center Clinical Studies (U34/U01)

For high-risk clinical studies (see NOT-DK-051) that involve more than one research centers, NIDDK uses a two-part process that usually requires use of a U34 planning grant followed by a separate application for the clinical trial or study (U01). A single clinical research center may encompass one or more physical locations where the clinical trial is being conducted—i.e., where study participants are recruited, intervened upon, or have outcomes assessed under a single protocol—as long as all locations are under the overall direction of a single investigator.

For more information on the U34, view NIDDK’s U34 page, PAR-24-094, and NOT-DK-20-051.

For more information on the U01, view NIDDK’s U01 page, PAR-24-103, PAR-24-102, and NOT-DK-20-051.

Investigator-initiated Ancillary Studies to Major Ongoing Clinical Studies

NIDDK encourages ancillary studies to its large multi-center clinical trials and clinical studies. These major studies offer unique opportunities to conduct additional investigations that are not part of the parent protocol. These new studies must be within the mission of NIDDK. Applications for ancillary studies must have the approval of the parent study and may be submitted to PA-20-185 or other appropriate NOFOs.

Biosamples for Use in Research (X01)

Many of the large clinical studies funded by the NIDDK collect non-renewable biosamples, such as plasma and urine, and associated data for analysis and future study. Biosamples are stored in the NIDDK Central Repository. The X01 mechanism provides access for researchers who are interested in using these biosample resources in their clinical studies. View PAR-19-319.

Related Links

NIH Resources

Last Reviewed October 2023