Psychometric Properties of the Participation Scale among Former Buruli Ulcer Patients in Ghana and Benin

Background: Buruli ulcer is a stigmatising disease treated with antibiotics and wound care, and sometimes surgical intervention is necessary. Permanent limitations in daily activities are a common long term consequence. It is unknown to what extent patients perceive problems in participation in social activities. The psychometric properties of the Participation Scale used in other disabling diseases, such as leprosy, was assessed for use in former Buruli ulcer patients. Methods: Former Buruli ulcer patients in Ghana and Benin, their relatives, and healthy community controls were interviewed using the Participation Scale, Buruli Ulcer Functional Limitation Score, and the Explanatory Model Interview Catalogue to measure stigma. The Participation Scale was tested for the following psychometric properties: discrimination, floor and ceiling effects, internal consistency, inter-item correlation, item-total correlation and construct validity. Results: In total 386 participants (143 former Buruli ulcer patients with their relatives (137) and 106 community controls) were included in the study. The Participation Scale displayed good discrimination between former Buruli ulcer patients and healthy community controls. No floor and ceiling effects were found. Internal consistency (Cronbach's alpha) was 0.88. In Ghana, mean inter-item correlation of 0.29 and item-total correlations ranging from 0.10 to 0.69 were found while in Benin, a mean inter-item correlation of 0.28 was reported with item-total correlations ranging from −0.08 to 0.79. With respect to construct validity, 4 out of 6 hypotheses were not rejected, though correlations between various constructs differed between countries. Conclusion: The results indicate the Participation Scale has acceptable psychometric properties and can be used for Buruli ulcer patients in Ghana and Benin. Future studies can use this Participation Scale to evaluate the long term restrictions in participation in daily social activities of former BU patients. Author Summary: Buruli ulcer is a stigmatising condition caused by infection with Mycobacterium ulcerans. Besides the long term medical consequences, Buruli ulcer may lead to participation restrictions in social life. The Participation Scale intends to assess perceived participation restrictions; however, this instrument has been developed in patients affected by leprosy and other disabling conditions, and has never been used before among Buruli ulcer patients. We aimed to analyze the reliability and validity of the Participation Scale among former Buruli ulcer patients in Ghana and Benin. This study included former Buruli ulcer patients from 2 different treatment sites, along with their relatives and healthy community controls residing in similar geographical areas. Former Buruli ulcer patients were interviewed using the Participation Scale, Buruli Ulcer Functional Limitation Score, and the Explanatory Model Interview Catalogue to measure stigma. Relatives and healthy community controls were interviewed using the Participation Scale. We tested the Participation Scale for discrimination, floor and ceiling effects, internal consistency, inter-item correlation, item-total correlation and construct validity. The results of the analysis suggest that the Participation Scale has acceptable psychometric properties. As such, the instrument can be used to assess participation restrictions among former Buruli ulcer patients in Ghana and Benin.