Content Validity Assessment of the Revised Illness Perception Questionnaire in CKD Using Qualitative Methods.

Some IPQ-R subscales may pose content validity concerns in the non-dialysis CKD population. Item modification for comprehensibility (personal control) and relevance (treatment control) should be considered. Future studies should explore the impact of a patient's symptom experience on IPQ-R validity, especially in populations like CKD with a higher proportion of asymptomatic patients.