A Nationwide Factorial Randomized Trial of Electronic Nudges to Patients with Chronic Kidney Disease and Their General Practices for Increasing Guideline-Directed Medical Therapy: The NUDGE-CKD Trial

Background: Many individuals with chronic kidney disease (CKD) face considerable but modifiable risk of cardiovascular and renal outcomes due to suboptimal implementation of guideline-directed medical therapy (GDMT). We investigated whether electronic letter-based nudges delivered to individuals with CKD and their general practices could increase GDMT uptake. Methods: This was a nationwide 2x2 factorial implementation trial, with randomization at the patient and general-practice level, and analyzed at the patient level. All Danish adults with a hospital-diagnosis of CKD and access to the official Danish electronic letter system were individually randomized in a 1:1 ratio to usual care (no letter) or to receive an electronic letter-based nudge on GDMT in CKD; general practices of individuals with CKD were independently randomized (1:1) to receive no letter or an electronic informational letter on GDMT. Intervention letters were delivered on August 19, 2024. Data were collected through the Danish administrative health registries. Primary endpoint was a filled prescription of a renin-angiotensin system inhibitor (RASi) or a sodium-glucose cotransporter-2 inhibitor (SGLT2i) within 6 months of intervention delivery. Results: A total of 22,617 patients with CKD were randomized to the patient-level intervention, with 11,223 allocated to receive the electronic nudge letter and 11,394 to usual care. Separately, 1,540 general practices caring for 28,069 patients with CKD were randomized to the provider-level intervention, with 774 practices (13,959 patients) allocated to the intervention and 766 practices (14,110 patients) to usual care. During follow-up, 7,303 (65.1%) allocated to the patient-directed nudge had filled a prescription of RASi or SGLT2i compared with 7,505 (65.9%) in usual care (difference, 0.79 percentage points; 95% confidence interval (CI), -2.03 to 0.45; P=0.21). Among patients of practices receiving the provider-directed letter, 8,921 (63.9%) filled a prescription for RASi or SGLT2i compared with 9,086 (64.4%) in the usual care group (difference, -0.49 percentage points; 95%CI, -1.64 to 0.66; P=0.41). No interaction was observed between the two interventions (p interaction =0.85). Conclusions: In this nationwide pragmatic, 2x2 factorial implementation trial, electronic letter-based nudges on GDMT delivered to patients with CKD or their general practice did not increase the uptake of RASi or SGLT2i as compared with usual care.