The self-administered 24-Item geriatric pain measure (GPM-24-SA): Psychometric properties in three european populations of community-dwelling older adults

Abstract

Objective: To explore the feasibility and psychometric properties of a self-administered version of the 24-item Geriatric Pain Measure (GPM-24-SA). Design: Secondary analysis of baseline data from the Prevention in Older People-Assessment in Generalists' practices trial, an international multi-center study of a health-risk appraisal system. Participants: One thousand seventy-two community dwelling nondisabled older adults self-reporting pain from London, UK; Hamburg, Germany; and Solothurn, Switzerland. Outcome Measures: GPM-24-SA as part of a multidimensional Health Risk Appraisal Questionnaire including self-reported demographic and health-related information. Results: Among the 1,072 subjects, 655 had complete GPM-24-SA data, 404 had ≤30% missing GPM-24-SA data, and 13 had >30% missing GPM-24-SA data. In psychometric analyses across the three European populations with complete GPM-24-SA data, the measure exhibited stable internal consistency, good convergent, divergent and discriminant validity, and produced stable pain measurements. However, factor analysis indicated differences in the GPM-24-SA across sites with discrepancies mainly related to items of a single subscale that failed to load appropriately. Analyses including imputation for subjects with ≤30% missing data demonstrated psychometric properties comparable to complete data analyses suggesting that imputation in cases with ≤30% missing GPM-24-SA data provides sufficient information to generate a valid score. Conclusion: The GPM-24-SA is a promising tool for self-administered assessment of pain in community dwelling older adults. However, because of incomplete response and uncertainty in factor structure, further refinement and psychometric evaluation of the GPM-24-SA is needed before it could be recommended for widespread use. © 2008 by American Academy of Pain Medicine.