A scale to measure pain in non-verbally communicating older patients: the EPCA-2 Study of its psychometric properties.

We have constructed and validated the Elderly Pain Caring Assessment 2 (EPCA-2) an 8 items behavioural scale to rate the intensity of pain in non-verbally communicating older (age 65 years) patients (NVC-OP). It was postulated that the assessed pain had two dimensions (signs outside and during caregiving). The first version of the scale was constructed on the basis of the results of a survey among 48 experienced nurses and caregivers and of a review of the literature. After testing of three intermediate versions, the psychometrics properties of the final version were studied on 340 NVC-OP. The face and content validities were good. Convergent validity: the total score was well correlated both with a pain global clinical score given by two highly experienced observers (r(s)=0.846) and with the opioid dose prescribed in a sub-group of patients (r(s)=0.698). The discriminant and divergent validities were satisfactory. After factor analysis, the internal structure of the scale was consistent with the postulated two-dimensional structure of the construct. The inter-rater reliability was very good (ICC=0.877) and is always equally good irrespective of the status (doctor, nurse and caregiver) of the raters. The internal consistency was highly satisfactory (alpha=0.79). The responsiveness evaluated in 4 ways was always very good. EPCA-2 may provided nurses, caregivers and doctors with a validated instrument for pain assessment in NVC-OP.