Shoulder-Specific Patient-Reported Outcome Measures for Use in Patients With Head and Neck Cancer: An Assessment of Reliability, Construct Validity, and Overall Appropriateness of Test Score Interpretation Using Rasch Analysis.

Abstract

The purpose of this study was to investigate the construct validity and overall appropriateness of test score interpretation of 4 shoulder-related patient-reported outcome (PRO) measures for use in a population of patients with head and neck cancer using Rasch analysis. One hundred eighty-two individuals who had received a neck dissection procedure within the past 2weeks to 18months were recruited for this cross-sectional psychometric study. Rasch methodologies were used to investigate scale dimensionality, scale hierarchy, response scale structure, and reliability of Disabilities of the Arm, Shoulder and Hand (DASH), QuickDASH, Shoulder Pain and Disability Index (SPADI), and Neck Dissection Impairment Index (NDII). DASH did not meet criteria for unidimensionality and was deemed inappropriate for use in this sample. The QuickDASH, SPADI, and NDII were all determined to be unidimensional. All scales had varying issues with person and item misfit, differential item functioning, coverage of ability levels, and optimal rating scale requirements. The NDII met most requirements. All measures were found to meet thresholds for person and item separation as well as reliability statistics. Rasch analysis indicates the NDII is the most appropriate measure studied for this population. The QuickDASH and SPADI are recommended with reservation, whereas the DASH is not recommended. This study demonstrates the use of objective methodologies, using Rasch analysis, to validate PRO recommendations provided by clinical experts in forums such as the Evaluation Database to Guide Effectiveness (EDGE) TaskForce, which are based upon a comprehensive literature review, consideration of published psychometric properties, and expert consensus. Use of Rasch methodologies demonstrates weaknesses in this model and provides opportunities to strengthen recommendations for clinicians.