The Geriatric Pain Measure: validity, reliability and factor analysis.

BACKGROUND: Pain is a multidimensional experience that should be evaluated beyond an estimate of intensity. A multidimensional pain measure has not been developed for older persons undergoing comprehensive geriatric assessment.
OBJECTIVE: To develop and evaluate validity and reliability of a multidimensional pain assessment instrument for older persons. RESEARCH
DESIGN: A series of steps in instrument development and evaluation.
SUBJECTS: A total of 176 subjects (mean age 84 +/- 6.0 years) in ambulatory geriatric clinics; 64% were women, and 73% had a history of chronic pain. MEASUREMENTS: Measurements included the Geriatric Pain Measure (GPM), the McGill Pain Questionnaire, Yesavage GDS, Katz ADLs, Lawton IADLs, Tinetti Gait and Balance, Folstein MMSE, and other demographic and clinical characteristics from interview and chart review.
RESULTS: The GPM demonstrated a standardized alpha = 0.9445, homogeneity ratio =0.457, and average inter-item correlation =0.415. A subgroup of 50 subjects demonstrated concurrent validity of the GPM in comparison with the McGill Pain Questionnaire (Pearson's r correlation 0.6269 (P < .0000). Test-retest reliability was demonstrated in another subgroup of 50 subjects who repeated the GPM within 48 to 72 hours (Pearson's r = 0.9018; P < .0000). Factor analysis revealed five clusters of components: Pain Intensity, Disengagement, Pain with Ambulation, Pain with Strenuous Activities, and Pain with Other Activities.
CONCLUSIONS: The GPM is a 24-item questionnaire that is easy to administer and has significant validity and reliability in older persons with multiple medical problems. The GPM may be a useful addition to the multidimensional geriatric assessment process.