Cross-cultural adaptation and measurement properties of the Brief Illness Perception Questionnaire-Dutch Language Version.

Objective: Ever since Engel's Biopsychosocial Model (1977) emotions, thoughts, beliefs and behaviors are accepted as important factors of health. The Brief Illness Perception Questionnaire (Brief IPQ) assesses these beliefs. Aim of this study was to cross-culturally adapt the Brief IPQ into the Brief IPQ Dutch Language Version (Brief IPQ-DLV), and to assess its face validity, content validity, reproducibility, and concurrent validity.

Methods: Beaton's guideline was used for cross-culturally adaptation. Face and content validity were assessed in 25 patients, 15 physiotherapists and 24 first-grade students. Reproducibility was established in 27 individuals with chronic obstructive pulmonary disease using Cohen's kappa coefficient (K(w)) and the Smallest Detectable Change (SDC). Concurrent validity was assessed in 163 patients visiting 11 different physical therapists.

Results: The Brief IPQ-DLV is well understood by patients, health care professionals and first-grade students. Reliability at 1 week for the dimensions Consequences, Concern and Emotional response K(w)>0.70, for the dimensions Personal control, Treatment control, Identity, K(w)<0.70. A time interval of 3 weeks, reliability coefficients were lower for almost all dimensions. SDC was between 2.45 and 3.37 points for individual measurement purposes and between 0.47 and 0.57 points for group evaluative measurement purposes. Concurrent validity showed significant correlations (P<.05) for four out of eight illness perceptions (IPs) dimensions.

Conclusion: The face and content properties were found to be acceptable. The reproducibility and concurrent validity needs further investigated.