Electronic Letters to Improve Patient Activation in IHD: The NUDGE-IHD Trial (NUDGE-IHD)

March 8, 2026 updated by: Tor Biering-Sørensen

NUDGE-IHD: A Nationwide Pragmatic Randomized Trial of Electronic Nudges to Increase Patient Activation to Support Risk-factor Control in Ischemic Heart Disease

The goal of this clinical trial is to learn whether simple electronic information letters can increase patient activation and improve risk-factor monitoring in adults in Denmark with ischemic heart disease (IHD) who have LDL cholesterol above the recommended treatment target. A subgroup of participants with elevated lipoprotein(a) [Lp(a)] will also be randomized to receive an additional information letter.

The main questions the study aims to answer are:

  • Does sending an electronic letter about elevated LDL cholesterol increase the proportion of patients who have at least one LDL-cholesterol test within 6 months?
  • Among patients with ischemic heart disease and elevated Lp(a), does receiving an information letter about Lp(a) increase patient activation, reflected by cardiometabolic risk-factor monitoring?

Because this is a randomized trial, researchers will compare people who receive the electronic letter(s) with people who do not receive any letter to determine whether the letters encourage patients to take action, such as obtaining laboratory tests or contacting their doctor.

Participants will:

  • Receive an electronic letter through Denmark's national digital mailbox system (Digital Post) or receive no letter, depending on random assignment.
  • Continue their usual health care, with no additional visits, treatments, or procedures required for the study.
  • Have all study information collected from existing Danish nationwide health registries.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

This study is a nationwide, pragmatic, registry-based, partially factorial randomized trial conducted in Denmark. The trial evaluates whether simple electronic information letters ("nudges") can increase patient activation and support guideline-directed risk-factor monitoring among persons with ischemic heart disease (IHD) who have LDL cholesterol levels above guideline-recommended treatment targets in routine clinical care.

The primary study population consists of adults with documented ischemic heart disease and LDL cholesterol above the recommended target level. Eligible participants are identified using Danish nationwide health registries and randomized 1:1 to receive either an electronic information letter addressing elevated LDL cholesterol (the "LDL letter") or no letter. The LDL letter provides general, non-technical information about LDL cholesterol as a cardiovascular risk factor in ischemic heart disease and encourages recipients to consult their physician if relevant.

A secondary study population is defined as a subset of the primary population with elevated lipoprotein(a) [Lp(a)] levels identified from laboratory registry data. Participants in this subgroup are independently randomized 1:1 to receive or not receive an additional electronic information letter addressing elevated Lp(a) (the "Lp(a) letter"). The Lp(a) letter provides information on Lp(a) as a genetically determined and independent cardiovascular risk factor and emphasizes the importance of optimizing other modifiable risk factors. The two randomizations are conducted independently, resulting in a partially factorial design in which participants with elevated Lp(a) may receive no letter, the LDL letter only, the Lp(a) letter only, or both letters.

All intervention letters are delivered through Denmark's mandatory national digital mailbox system (Digital Post). The interventions are informational and non-invasive. The study does not involve any in-person visits, clinical procedures, or changes to usual medical care.

The primary outcome is disease-related patient activation, defined as the proportion of participants with at least one LDL cholesterol measurement recorded within 6 months after randomization. Secondary outcomes include general patient activation, assessed by the number of healthcare contacts in general practice or outpatient hospital settings, and cardiometabolic risk-factor monitoring, defined as the proportion of participants with at least one cardiometabolic blood test (lipid profile, hemoglobin A1c, or creatinine) within 6 months after randomization. Additional exploratory outcomes related to laboratory testing, healthcare utilization, medication use, and clinical events are assessed during longer-term follow-up.

All baseline characteristics, outcomes, and follow-up data are obtained from Danish nationwide health and administrative registries. Due to the registry-based and informational nature of the interventions, informed consent is not required. The primary analysis is conducted 6 months after randomization, with additional exploratory follow-up extending up to 5 years.

Study Type

Interventional

Enrollment (Estimated)

100000

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Denmark
    • Region Sjælland
      • Hellerup, Region Sjælland, Denmark, 2900
        • Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, 2900
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria

  • Alive on identification date
  • Diagnosis of IHD defined as either an A or B diagnosis code of I20-I25 in the Danish National Patient Register first registered > 6 months prior to identification date
  • Latest available LDL-C is over 1.4 mmol/l measured up to 3 years prior to the identification date, defined using NPU codes NPU01568, NPU10171 or DNK35308 from the Danish National Laboratory Register
  • Age >= 18 years and <= 85 on identification date

Exclusion criteria

  • Nursing home residents
  • Exemption from and thus not access to Digital Post

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Health Services Research
  • Allocation: Randomized
  • Interventional Model: Factorial Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: LDL letter only
Participants randomized to the LDL-C letter but not the Lp(a) letter
Behavioral: LDL-C information letter
An electronically delivered informational letter communicating the participant's elevated LDL-C level and its relevance to ASCVD, with encouragement to consult their physician if relevant. Delivered via the Danish Digital Post system.
Experimental: Lp(a) letter only
Participants randomized to the Lp(a) letter but not the LDL-C letter.
Behavioral: Lp(a) information letter
An electronically delivered informational letter describing elevated Lp(a) as a genetically determined cardiovascular risk factor, with encouragement to discuss risk factor optimization with a physician if relevant.
No Intervention: No letter
Participants randomized to no LDL-C letter and to no Lp(a) letter
Experimental: LDL-C and Lp(a) letter
Participants randomized to the LDL-C letter and the Lp(a) letter
Behavioral: LDL-C information letter
An electronically delivered informational letter communicating the participant's elevated LDL-C level and its relevance to ASCVD, with encouragement to consult their physician if relevant. Delivered via the Danish Digital Post system.
Behavioral: Lp(a) information letter
An electronically delivered informational letter describing elevated Lp(a) as a genetically determined cardiovascular risk factor, with encouragement to discuss risk factor optimization with a physician if relevant.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
the proportion of participants with at least one LDL-C measurement within 6 months following randomization
Time Frame: 6 months after randomization
Whether the participant has at least one LDL-C laboratory measurement recorded in the Danish national laboratory registries within 6 months after randomization
6 months after randomization

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of healthcare contacts (general practice or outpatient hospital) within 6 months following randomization
Time Frame: 6 months after randomization
Total number of healthcare contacts, defined as general practice contacts (in-person, telephone, or electronic) or outpatient hospital visits, recorded in national registries within 6 months after randomization.
6 months after randomization
At least one cardiometabolic blood test
Time Frame: Within 6 months after randomization
Proportion of participants with at least one cardiometabolic blood test (lipid profile, hemoglobin A1c, or creatinine) recorded in Danish nationwide laboratory registries during follow-up.
Within 6 months after randomization

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Tor Biering-Sørensen

Collaborators

Novartis

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

April 1, 2026

Primary Completion (Estimated)

October 1, 2026

Study Completion (Estimated)

October 1, 2026

Study Registration Dates

First Submitted

December 9, 2025

First Submitted That Met QC Criteria

January 28, 2026

First Posted (Actual)

February 2, 2026

Study Record Updates

Last Update Posted (Actual)

March 10, 2026

Last Update Submitted That Met QC Criteria

March 8, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NUDGE-IHD

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Data will be collected from Danish administrative health registries, which are subject to Danish legislation and can only be made available to a third party under certain conditions. Please contact the sponsor-investigator in case of any inquiries.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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