Evaluating the Turkish validity and reliability of the Brief Illness Perception Questionnaire in periodontal diseases

The Brief Illness Perception Questionnaire (Brief IPQ) is a widely used multifactorial scale that assesses the individuals' perceptions of illness. Although there are studies investigating the psychometric properties of the Brief IPQ in many languages, the Turkish version of Brief IPQ on periodontal diseases has not been revealed so far. This study aimed to evaluate the Turkish validity and reliability of the Brief IPQ and contribute to the literature. It is also aimed to evaluate the patients' illness perception with periodontal disease and to reveal the possible effects of the disease on the patients' daily life.

This cross-sectional study was conducted with 209 patients with periodontal diseases (137 gingivitis and 72 periodontitis cases). Sociodemographic characteristics and clinical periodontal measurements of all patients were recorded. The Turkish versions of the Brief IPQ and the HAD Scale were applied to the patients via face-to-face. The construct validity was determined using confirmatory factor analysis. Test-retest reliability and internal consistency were performed using ICC test and Cronbach's alpha, respectively. The concurrent validity was determined by using Spearman's correlation coefficient.

The confirmatory factor analysis showed that the scale has one factor. The Spearman's correlation coefficient results were found 0.843 and 0.854 for concurrent validity. Cronbach's alpha value of the scale was 0.944 in the internal consistency analysis. ICC value was found to be 0.987 for test-retest reliability. Floor/ceiling effects were considered not to be present.

It was found that the Turkish version of The Brief Illness Perception Questionnaire is valid and reliable. Brief IPQ may be used to determine the illness perception in patients with periodontal diseases.