Comprehensive assessment of peri-operative fatigue: development of the Identity-Consequence Fatigue Scale

Objective: Fatigue is one of the complaints most widely reported during peri-operative periods. However, despite its prevalence, the aetiology of this fatigue remains poorly understood. Recent meta-analysis suggests that the limited applicability of existing fatigue measures is contributing to the current lack of understanding. This research therefore sought to use a rigorous analytic process to develop a comprehensive measure of fatigue suitable for use with recovering surgical patients. Methods: Content analysis was undertaken to investigate the structure of 55 items initially generated. Self-report questionnaires were then distributed to surgical out-patients, and the 177 responses analysed using principal components analysis. Once item selection was finalized, the convergent and discriminant validity of the new measure was assessed. Results: The new measure, the Identity-Consequence Fatigue Scale (ICES), has 28 items and five subscales. All subscales show high internal reliability, and reentry of deleted items showed that the finalized items form a robust component structure. Discriminant validity analysis confirmed that all ICFS subscales are distinctive from depression and anxiety. Convergent validity analysis confirmed the extent to which the ICFS assesses Fatigue-Consequences is a unique feature of the new measure. Conclusion: The ICFS has a clear and stable structure that offers more comprehensive assessment of fatigue than provided by the measures most widely used in postsurgical fatigue (PSF) literature to date. (c) 2006 Elsevier Inc. All rights reserved.