Nudging patients with chronic kidney disease at screening to visit physicians: A protocol of a pragmatic randomized...

Strategies for an effective intervention after chronic kidney disease (CKD) screening have not been well examined. We describe the rationale and design of a protocol of a pragmatic randomized controlled trial (RCT) to test the effect of a behavioral intervention using the nudge approach in behavioral economics on CKD patients' visiting behaviors to physicians and change in their kidney function after CKD screening.

The RCT will include CKD patients (N = 4500) detected at screening (estimated glomerular filtration rate [eGFR] <60 mL/min/1.74 m² or urine protein ≥1+), aged 40-63 years. The two intervention groups will receive a "usual letter" and "nudge-based letter," while the control group will only receive a conventional follow-up. Our primary outcome is proportion of patients' visiting physicians for 6 months after the intervention; the secondary outcome is change in the eGFR at 2 years after the intervention.

We developed an efficient intervention program after CKD screening and designed the pragmatic RCT to assess its effectiveness in the real world. Our trial is unique in that it investigates the effect of the nudge approach in behavioral economics. By the end of 2018, we have enrolled 1,692 participants, and randomized 677 participants into the usual letter group, 677 participants into the nudge-based letter group, and 338 participants into the control group. We have confirmed that health checkup data could identify a large number of eligible participants.

The trial's results will contribute to filling in the gap between screening and subsequent medical interventions for preventing CKD progression.