Critical appraisal of instruments to assess illness representations in rheumatology.
A first search (MEDLINE, EMBASE, PsycINFO) identified articles describing development of instruments assessing illness representations. A second search identified articles applying them in rheumatology. Appraisal was performed using checklists.
Five instruments were identified: the Illness Perception Questionnaire (IPQ), the Revised Illness Perception Questionnaire (IPQ-R), the Illness Cognition Questionnaire (ICQ), the Implicit Models of Illness Questionnaire (IMIQ) and the Meaning of Illness Questionnaire (MIQ). The number of items varied from 18 to 70. Internal consistency was good. Construct validity was moderate to good for all instruments, but was not tested for the IMIQ. Predictive validity was assessed for the ICQ and IPQ and was low to moderate. Sensitivity to change was tested for ICQ and was good. Applications in rheumatology are increasing. Significant relationships with different outcomes and additional evidence for predictive validity were found.
Five instruments that assess illness representations can be used in rheumatology. The number of subscales and items vary. The ICQ and IPQ are most extensively validated and have been most frequently applied in rheumatology. Illness representations have relevant associations with self-report and objective outcomes. They should be considered when exploring health in rheumatology.