Developing and Evaluating a WeChat-Based Applet Fluid Intake Reminder on Enhancing Fluid Adherence in Postoperative Patients With Urinary Calculi: Protocol for a Randomized Controlled Trial

Background: Urinary calculi (UC), affecting 1%-13% globally, pose a significant health burden due to high recurrence rates (up to 50% within 10 years) and substantial health care costs. Adequate fluid intake is a cornerstone of prevention; yet, its adherence remains poor due to forgetfulness, lifestyle barriers, and limited patient education. Existing mobile health interventions for UC prevention often lack medical oversight and clinical validation. WeChat-based digital therapeutic intervention may have a positive effect on fluid adherence in this patient group. Objective: Our objective is to develop a WeChat applet to improve hydration behavior and reduce stone recurrence among postoperative patients with UC. Methods: This is an open-label, 2-arm, parallel-group randomized controlled trial. We will recruit 148 participants from China's tertiary hospital and randomly allocate them in a ratio of 1:1 to the intervention or control group. The intervention group received standard postoperative care supplemented by the WeChat-Based Applet Fluid Intake Reminder (WAFIR), which delivers personalized fluid intake reminders, urine color monitoring, 24-hour fluid intake and urine output tracking, and evidence-based educational content on hydration and urolithiasis management. The control group receives standard care of general discharge instructions from nurses. The primary outcome is the fluid adherence, measured by 24-hour fluid intake and urine volume; secondary outcome measures are the Wisconsin Stone Quality of Life Questionnaire, Patient Health Questionnaire-9, Electronic Health Literacy Scale, physical activity (International Physical Activity Questionnaire-Short Form), and recurrence rate of UC. Outcomes are measured before intervention (T0) and after a 1-month (T1) and 3-month (T2) follow-up period. Intention-to-treat analysis, 2-tailed t tests, and repeated measures ANOVA will be used to compare outcomes; statistical significance is set at a P