The clinimetric properties of the COMFORT scale: A systematic review.

The COMFORT scale is a measurement tool to assess distress, sedation and pain in nonverbal paediatric patients. Several studies have described the COMFORT scale, but no formal assessment of the methodological quality has been undertaken. Therefore, we performed a systematic review to study the clinimetric properties of the (modified) COMFORT scale in children up to 18 years. We searched Central, CINAHL, Embase, Medline, PsycInfo and Web of Science until December 2014. The selection, data extraction and quality assessment were performed independently by two reviewers. Quality of the included studies was appraised using the COSMIN checklist. We found 30 studies that met the inclusion criteria. Most participants were ventilated children up to 4 years without neurological disorders. The results on internal consistency and interrater reliability showed values of >0.70 in most studies, indicating an adequate reliability. Construct validity resulted in correlations between 0.68 and 0.84 for distress, between 0.42 and 0.94 for sedation and between 0.31 and 0.96 for pain. The responsiveness of the (modified) COMFORT scale seems to be adequate. The quality of the included studies ranged from poor to excellent. The COMFORT scale shows overall an adequate reliability in providing information on distress, sedation and pain. Construct validity varies from good to excellent for distress, from moderate to excellent for sedation, and from poor to excellent for pain. The included studies were clinically and methodologically heterogeneous, hampering firm conclusions. WHAT DOES THIS REVIEW ADD?: An in-depth assessment of the clinimetric properties of the COMFORT scale. The COMFORT scale shows overall an adequate reliability in providing information on distress, sedation and pain. Construct validity varies from good to excellent for distress, from moderate to excellent for sedation, and from poor to excellent for pain.