Development and preliminary evaluation of the validity and reliability of a revised illness perception questionnaire...

Diverging perceptions between individual patients with somatic diseases and their healthcare professionals might cause problems in communication and decision-making. To date, no measurement tool is available to compare the illness perceptions between these two groups. The Revised Illness Perception Questionnaire (IPQ-R) is a validated, widely used instrument in many patient populations with somatic conditions. The aim of this study was to adapt the IPQ-R to a healthcare professional's version (IPQ-R HP) and to perform a preliminary evaluation of its validity and reliability.

After adaptation of the IPQ-R HP, 17 doctors from 3 general hospitals and 9 head nurses from a university hospital evaluated the face and content validity of the IPQ-R HP. The results were quantified using the content validity index (CVI) and a modified kappa index (k*). For the reliability measurements a group of nurses from 4 nursing wards participated at 2 time points with an interval of 4 weeks. Internal consistency and test-retest reliability were calculated.

Twenty-eight of the 38 items demonstrated excellent content validity and four items showed good content validity. Four items had a sufficient k* and two items had a low CVI. The average CVI of the 7 dimensions ranged from 0.66 to 0.89. The Cronbach's alpha scores for the seven dimensions, intraclass coefficients and effect size estimates were acceptable.

This preliminary evaluation of the IPQ-R HP shows an acceptable to good validity and reliability. Further exploration of the psychometric properties of this questionnaire in a large cohort of healthcare professionals is warranted.