Rationale and Design of NUDGE-CKD: A Nationwide Randomized Factorial Trial of Electronic Nudges for Increasing Guideline-Directed Medical Therapy in Chronic Kidney Disease

BACKGROUND: Treatment guidelines for chronic kidney disease (CKD) recommend sodium-glucose cotransporter 2 inhibitors (SGLT2i) as first-line treatment for a broad range of individuals with CKD, alongside renin-angiotensin system inhibitors (RASi). However, adoption of guidelines in clinical practice is often delayed, potentially leading to avoidable associated morbidity and mortality. Effective strategies are needed to improve implementation of guideline-directed medical therapy (GDMT) in patients with CKD. This trial will evaluate the effectiveness of electronic letter-based nudges, delivered via the Danish governmental electronic letter system to individuals with CKD, their general practices, or both, in increasing GDMT in individuals with CKD.

METHODS: NUDGE-CKD is a 2 × 2 factorial, nationwide implementation trial, with randomization at both the general practice and patient level. All Danish citizens with CKD and access to the official Danish electronic letter system were randomized in a 1:1 ratio to usual care (no letter) or to receive an electronic letter-based nudge on GDMT in CKD. All Danish general practices with a patient with CKD on their patient panel were also randomized 1:1 to usual care (no letter) or to receive an electronic informational nudge letter on GDMT in CKD. Data are collected through the Danish administrative health registries. The primary endpoint is a prescription of RASi or SGLT2i within 6 months of intervention delivery based on fill records. Secondary endpoints include components of the primary endpoint, as well as proportion of new CKD GDMT users. Prespecified exploratory endpoints include filled prescriptions of other cardio-renal-protective medications, general practice contacts, assessment of renal biomarkers and downstream clinical outcomes. A total 22,617 individuals with CKD were randomized to the patient-level intervention, and 28,069 individuals with CKD across 1,540 general practices were randomized to the general practice-level intervention. Intervention letters were delivered on August 19, 2024, and follow-up is currently ongoing (end of follow-up for primary endpoint: February 19, 2025).

DISCUSSION: NUDGE-CKD is the first nationwide randomized trial of electronic letter-based nudges delivered to individuals with CKD and their general practices to increase uptake of GDMT in individuals with CKD. The trial will provide evidence into the usefulness of direct communication with patients and healthcare providers for real-world implementation of GDMT.

TRIAL REGISTRATION: Clinicaltrials.gov: NCT06300086, registered March 7, 2024 (https://clinicaltrials.gov/study/NCT06300086).