Nationwide Utilization of Danish Government Electronic letter system for increasing inFLUenza vaccine uptake (NUDGE-FLU): Study protocol for a nationwide randomized implementation trial.

BACKGROUND: Annual influenza vaccination is widely recommended in older adults and other high-risk groups including patients with cardiovascular disease. The real-world effectiveness of influenza vaccination is limited by suboptimal uptake and effective strategies for increasing vaccination rates are therefore needed. The purpose of this trial is to investigate whether behavioral nudges digitally delivered via the Danish nationwide mandatory governmental electronic letter system can increase influenza vaccination uptake among older adults. METHODS: The NUDGE-FLU trial is a randomized implementation trial randomizing all Danish citizens aged 65 years and above without an exemption from the Danish mandatory governmental electronic letter system to receive no digitally delivered behavioral nudge (usual care arm) or to receive one of 9 electronic letters (intervention arms) each leveraging different behavioral science strategies. The trial has randomized 964,870 participants with randomization clustered at the household level (n = 691,820 households). Intervention letters were delivered on September 16, 2022, and follow-up is currently ongoing. All trial data are captured using the nationwide Danish administrative health registries. The primary end point is the receipt of an influenza vaccine on or before January 1, 2023. The secondary end point is time to vaccination. Exploratory end points include clinical events such as hospitalization for influenza or pneumonia, cardiovascular events, all-cause hospitalization, and all-cause mortality. DISCUSSION: The nationwide randomized NUDGE-FLU trial is one of the largest implementation trials ever conducted and will provide important insights into effective communication strategies to maximize vaccination uptake among high-risk groups. TRIAL REGISTRATION: Clinicaltrials.gov: NCT05542004, registered September 15, 2022, https://clinicaltrials.gov/ct2/show/NCT05542004.

Feasibility of randomizing Danish citizens aged 65-79 years to high-dose quadrivalent influenza vaccine vs. standard-dose quadrivalent influenza vaccine in a pragmatic registry-based setting: rationale and design of the DANFLU-1 Trial.

BACKGROUND: High-dose influenza vaccines provide better protection against influenza infection than standard-dose in persons aged 65 years and above; however, in most countries, high-dose vaccines are not widely implemented. Assessing the relative effectiveness of high-dose compared to standard-dose vaccines on hospitalizations and mortality would enable more robust public health and cost-effectiveness estimates. This study aims to investigate the feasibility of conducting a pragmatic randomized clinical trial in Denmark comparing high-dose to standard-dose vaccines utilizing existing vaccination infrastructure and the Danish nationwide health registries for data collection. METHODS: The DANFLU-1 trial (NCT05048589) is a pragmatic, open-label, active-controlled randomized trial randomizing Danish citizens aged 65-79 years to either high-dose quadrivalent influenza vaccine or standard-dose quadrivalent influenza vaccine. The study utilizes the infrastructure of a private vaccination provider (Danske Lægers Vaccinations Service) for recruitment, inclusion, randomization, and vaccination. All collection of baseline and follow-up data including safety monitoring is performed centrally by the Department of Cardiology at Herlev and Gentofte Hospital, Copenhagen, Denmark using the Danish nationwide health registries. The study aims to include 40,000 participants during the 2021/2022 influenza season. The primary endpoints address feasibility and include the number of participants enrolled, randomization balance, and representativeness compared to the Danish general population. Relative vaccine effectiveness will also be assessed, however, this feasibility study is not powered for clinical outcomes and may be affected by the COVID-19 pandemic. DISCUSSION: The DANFLU-1 study is investigating the feasibility of conducting a large-scale pragmatic clinical trial in Denmark utilizing existing infrastructure and the Danish nationwide registries. This will provide valuable insight, especially for potential future fully powered vaccine trials, but also for trials wishing to investigate other interventions. TRIAL REGISTRATION: Clinicaltrials.gov : NCT05048589 , registered September 17, 2021.

Feasibility of randomizing Danish citizens aged 65–79 years to high-dose quadrivalent influenza vaccine vs. standard-dose quadrivalent influenza vaccine in a pragmatic registry-based setting: rationale and design of the DANFLU-1 Trial

Background High-dose influenza vaccines provide better protection against influenza infection than standard-dose in persons aged 65 years and above;however, in most countries, high-dose vaccines are not widely implemented. Assessing the relative effectiveness of high-dose compared to standard-dose vaccines on hospitalizations and mortality would enable more robust public health and cost-effectiveness estimates. This study aims to investigate the feasibility of conducting a pragmatic randomized clinical trial in Denmark comparing high-dose to standard-dose vaccines utilizing existing vaccination infrastructure and the Danish nationwide health registries for data collection. Methods The DANFLU-1 trial (NCT05048589) is a pragmatic, open-label, active-controlled randomized trial randomizing Danish citizens aged 65–79 years to either high-dose quadrivalent influenza vaccine or standard-dose quadrivalent influenza vaccine. The study utilizes the infrastructure of a private vaccination provider (Danske Lægers Vaccinations Service) for recruitment, inclusion, randomization, and vaccination. All collection of baseline and follow-up data including safety monitoring is performed centrally by the Department of Cardiology at Herlev and Gentofte Hospital, Copenhagen, Denmark using the Danish nationwide health registries. The study aims to include 40,000 participants during the 2021/2022 influenza season. The primary endpoints address feasibility and include the number of participants enrolled, randomization balance, and representativeness compared to the Danish general population. Relative vaccine effectiveness will also be assessed, however, this feasibility study is not powered for clinical outcomes and may be affected by the COVID-19 pandemic. Discussion The DANFLU-1 study is investigating the feasibility of conducting a large-scale pragmatic clinical trial in Denmark utilizing existing infrastructure and the Danish nationwide registries. This will provide valuable insight, especially for potential future fully powered vaccine trials, but also for trials wishing to investigate other interventions. Trial registration Clinicaltrials.gov: NCT05048589, registered September 17, 2021.

Echocardiographic abnormalities and predictors of mortality in hospitalized COVID-19 patients: the ECHOVID-19 study.

AIMS: The present study had two aims: (i) compare echocardiographic parameters in COVID-19 patients with matched controls and (2) assess the prognostic value of measures of left (LV) and right ventricular (RV) function in relation to COVID-19 related death. METHODS AND RESULTS: In this prospective multicentre cohort study, 214 consecutive hospitalized COVID-19 patients underwent an echocardiographic examination (by pre-determined research protocol). All participants were successfully matched 1:1 with controls from the general population on age, sex, and hypertension. Mean age of the study sample was 69 years, and 55% were male participants. LV and RV systolic function was significantly reduced in COVID-19 cases as assessed by global longitudinal strain (GLS) (16.4% ± 4.3 vs. 18.5% ± 3.0, P < 0.001), tricuspid annular plane systolic excursion (TAPSE) (2.0 ± 0.4 vs. 2.6 ± 0.5, P < 0.001), and RV strain (19.8 ± 5.9 vs. 24.2 ± 6.5, P = 0.004). All parameters remained significantly reduced after adjusting for important cardiac risk factors. During follow-up (median: 40 days), 25 COVID-19 cases died. In multivariable Cox regression reduced TAPSE [hazard ratio (HR) = 1.18, 95% confidence interval (CI) [1.07-1.31], P = 0.002, per 1 mm decrease], RV strain (HR = 1.64, 95%CI[1.02;2.66], P = 0.043, per 1% decrease) and GLS (HR = 1.20, 95%CI[1.07-1.35], P = 0.002, per 1% decrease) were significantly associated with COVID-19-related death. TAPSE and GLS remained significantly associated with the outcome after restricting the analysis to patients without prevalent heart disease. CONCLUSIONS: RV and LV function are significantly impaired in hospitalized COVID-19 patients compared with matched controls. Furthermore, reduced TAPSE and GLS are independently associated with COVID-19-related death.