A digital playful bladder and bowel diary for children: Development and content validation.

INTRODUCTION: Bladder and bowel dysfunction (BBD) is frequent in childhood and requires structured assessment strategies. Voiding diaries are commonly used tools; however, child-centered versions integrating bladder and bowel data in a digital and playful format remain limited. OBJECTIVE: To develop and perform content validation of a digital playful bladder and bowel diary for children, including an initial assessment of interface comprehension. METHODS: This methodological study was conducted in two phases. Phase 1 consisted of expert content validation of the instrument using the Item-level Content Validity Index (I-CVI), with participation of 15 specialists in lower urinary tract dysfunction in children. Phase 2 involved interface comprehension assessment with 13 children aged 6-11 years using a digital prototype. RESULTS: The initial overall I-CVI was 0.97. Ten items did not reach the predefined cut-off of 0.80 and were revised according to expert recommendations. After reassessment, all revised items achieved the minimum CVI threshold. The final validated version of the voiding and bowel diary block consisted of 61 items. In Phase 2, 60.7% of interface fields were fully understood, 32.1% showed comprehension rates between 84.62% and 92.31%, and two catheterization-related fields demonstrated comprehension below 80%. CONCLUSION: The study resulted in a digitally structured bladder and bowel diary with established content validity and initial evidence of interface comprehension among children. These findings represent an initial methodological step in the development of a child-centered digital tool for recording elimination habits.