Clinical trial NCT06030739: Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake Among Adults With Chronic Disease
Official title: Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake Among Adults With Chronic Disease
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Influenza
Behavior and Behavior Mechanisms
Keywords: Influenza
Vaccination
Nudging
Behavioral Science
Lead sponsor: Herlev and Gentofte Hospital
Sponsor class: OTHER
First posted: 2023-09-11
Enrollment: 299881
Sex: ALL
Minimum age (years): 18
Maximum age (years): 64
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: OTHER

Brief summary: In randomized clinical trials and observational studies, influenza vaccination has been shown to be effective in reducing influenza-related illness, hospitalizations, cardiovascular events, and mortality in select populations. However, the real-world effectiveness of influenza vaccination is limited by its uptake. This study will investigate whether digital behavioral nudges delivered via the official, mandatory Danish electronic letter system can increase influenza vaccine uptake among adults aged 18-64 years with chronic diseases.

Detailed description: The study is a prospective, randomized, open-label implementation trial. The study population will consist of persons aged 18-64 years identified as eligible for free-of-charge influenza vaccination due to a chronic condition. Subjects will be identified through Danish nationwide health registries using codes from the International Classification of Diseases, 10th revision (ICD-10). Individuals will be randomized to 1 of 7 arms (1 usual care arm and 6 intervention arms) with each testing different nudging strategies employing various behavioural economic principles. The interventions will be delivered through the official, mandatory Danish electronic letter system. All subject data will be retrieved from the Danish nationwide registries with the exception of information on intervention allocation. Endpoints will be retrieved at prespecified dates using prespecified search algorithms.

Eligibility criteria: Inclusion Criteria:

1. Age 18-64 years
2. Must be registered in the Danish nationwide registries as meeting at least one of the following eligibility criteria for free-of-charge influenza vaccination in the Danish public health system:

   1. Chronic lung disease
   2. Chronic cardiovascular disease other than hypertension
   3. Type 1 or type 2 diabetes mellitus
   4. Congenital or acquired immunodeficiency
   5. Impaired breathing due to muscular weakness
   6. Chronic renal or hepatic insufficiency
   7. Other chronic conditions with an increased risk of severe influenza as determined by the treating physician
3. Access to the official, mandatory Danish electronic mailbox system

Exclusion Criteria:

None

Primary outcomes:
measure: Number of participants who received an influenza vaccine
timeFrame: Up to 3 months
Secondary outcomes:
measure: Time from intervention delivery to influenza vaccination
timeFrame: Up to 3 months
Other outcomes:
measure: Number of participants with laboratory-confirmed influenza
timeFrame: Up to 8 months
measure: Number of participants with a hospitalization for influenza or pneumonia
timeFrame: Up to 8 months
measure: Number of participants with a hospitalization for any respiratory disease
timeFrame: Up to 8 months
measure: Number of participants with a hospitalization for any cardio-respiratory disease
timeFrame: Up to 8 months
measure: Number of participants with a hospitalization for any cardiovascular disease
timeFrame: Up to 8 months
measure: Number of participants with any hospitalization
timeFrame: Up to 8 months
measure: Total number of hospitalizations (first and recurrent)
timeFrame: Up to 8 months
measure: All-cause mortality
timeFrame: Up to 8 months
measure: Composite of incident heart failure, heart failure hospitalization, or cardiovascular death
timeFrame: Up to 8 months
measure: Composite of myocardial infarction, stroke, or cardiovascular death
timeFrame: Up to 8 months
measure: Composite of myocardial infarction, coronary revascularization, stroke, or cardiovascular death
timeFrame: Up to 8 months
measure: Number of participants with incident heart failure or heart failure hospitalization
timeFrame: Up to 8 months
measure: Total number of heart failure events (incident heart failure and first and recurrent heart failure hospitalizations)
timeFrame: Up to 8 months
measure: Cardiovascular death
timeFrame: Up to 8 months
measure: Number of participants with myocardial infarction
timeFrame: Up to 8 months
measure: Number of participants with coronary revascularization
timeFrame: Up to 8 months
measure: Number of participants with stroke
timeFrame: Up to 8 months
measure: Number of participants with incident atrial fibrillation or atrial fibrillation hospitalization
timeFrame: Up to 8 months
measure: Number of contacts to general practitioner (excluding vaccination visit)
timeFrame: Up to 8 months
measure: Number of participants with laboratory-confirmed COVID-19
timeFrame: Up to 8 months
measure: Number of participants with a hospitalization for COVID-19
timeFrame: Up to 8 months
measure: Number of participants who received a COVID-19 vaccine
timeFrame: Up to 3 months
measure: Number of participants who filled a prescription for any guideline-directed medical therapy for heart failure
timeFrame: Up to 8 months
measure: Total number of filled prescriptions for guideline-directed medical therapy for heart failure
timeFrame: Up to 8 months
measure: Number of participants who filled a prescription for a sodium-glucose cotransporter 2 inhibitor or glucagon-like peptide 1 receptor agonist
timeFrame: Up to 8 months
Locations:
city: Hellerup
country: Denmark
facility: Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte
state: Hovedstaden
Study officials:
affiliation: Center for Translational Cardiology and Pragmatic Randomized Trials, Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte
name: Tor Biering-Sørensen, MD, MSc, MPH, PhD
role: PRINCIPAL_INVESTIGATOR
References: