Development of a Questionnaire To Assess Phosphate Knowledge in Children With Chronic Kidney Disease and Their Caregivers

Abstract

Introduction: Hyperphosphataemia is a common complication of paediatric chronic kidney disease (CKD), despite the use of phosphate binders and the numerous strategies employed to reduce dietary phosphate (P) intake. This article describes the development of two self-administered semi-structured Phosphate Understanding and Knowledge Assessment (PUKA) questionnaires. The purpose of these is to assess challenges with adherence and measure declarative nutrition and procedural knowledge of phosphate in children and young people (CYP) with CKD and their caregivers. The aim is to create questionnaires that will be used for future studies investigating the relationship between knowledge and blood P-levels. Methods: Questions were generated from a literature review, clinical experience and feedback from a survey sent to UK paediatric kidney dietitians. The content, format and style of the questions were adapted and validated via expert consensus (including a psychologist, play therapist, paediatric kidney dietitians and nephrologists from the international Paediatric Renal Nutrition Taskforce, and our Young Persons’ Advisory Group), two caregivers and two CYP. A draft questionnaire was piloted with five caregivers and CYP with CKD to ensure face and content validity. To allow utilisation in a planned multi-centre trial, it was translated into five languages (Dutch, French, German, Italian and Turkish). The final English version questionnaires were used in a sample of CYP with CKD stages 4–5 and on dialysis (CKD4-5D), and caregivers, from three UK paediatric kidney centres. Results: From an initial pool of 80 questions, 37 were included in the final PUKA questionnaire. Thirteen were knowledge-based, and a knowledge score was developed. An adult and a child-friendly format were designed. Pilot testing confirmed face validity to ensure the questions were understandable. Forty-four CYP with CKD4-5D and 33 caregivers completed the final English PUKA questionnaires, with over 80% rating it easy to complete. The median time required to complete it was 11:06 min (IQR: 7:22–16:31). Conclusions: The PUKA questionnaires are a valid and reliable tool for measuring P-related knowledge and experiences of managing phosphate in CYP with CKD and their caregivers. © 2025 The British Dietetic Association Ltd.