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

Area of Science:

• Nephrology
• Psychology
• Health Measurement

Background:

• The Revised Illness Perception Questionnaire (IPQ-R) is a tool for assessing illness perceptions.
• Its psychometric properties are established in various diseases, but content validity in non-dialysis chronic kidney disease (CKD) is understudied.
• CKD's often asymptomatic nature may affect illness perception measurement.

Purpose of the Study:

• To explore the content validity of the IPQ-R in individuals with non-dialysis CKD.
• To identify potential issues with the IPQ-R's relevance and comprehensibility in this specific patient group.

Main Methods:

• Thirty-one non-dialysis CKD patients completed the IPQ-R.
• Interviews were conducted to assess participant agreement with their subscale scores.
• Qualitative analysis identified themes related to content validity.

Main Results:

• Overall participant agreement with IPQ-R scores was 79%.
• Agreement varied by subscale, with 'timeline' showing 100% agreement and 'personal control' (65%) and 'treatment control' (64%) showing lower agreement.
• Qualitative data highlighted concerns regarding the relevance and comprehensibility of 'personal control' and 'treatment control' items.

Conclusions:

• Certain IPQ-R subscales may present content validity challenges for non-dialysis CKD patients.
• Modifications to enhance comprehensibility and relevance of 'personal control' and 'treatment control' items are suggested.
• Further research should examine how symptom experience impacts IPQ-R validity in CKD populations.