Reliability of the Danish Abbey Pain Scale in severely demented and non-communicative older patients

Aim: To validate a Danish version of the observational Abbey Pain Scale (APS) in a geriatric ward.

Material and methods: The study population consisted of 50 old patients (70+ years), consecutively admitted to the geriatric wards of Aarhus University Hospital, Denmark, and fulfilling one of the following inclusion criteria: Mini Mental State Examination (MMSE) < 5, delirium, non-communicative aphasia, or unconsciousness. APS has six subscales and ranges from 0 (no pain) to 18 (worst pain). Criterion validity was assessed by using Verbal Rating Scale (VRS) as the gold standard. Cohen's kappa (k) was the measure of agreement. Inter-rater reliability was measured by two independent ratings of the same patient at the same time and assessed by Intraclass Correlation Coefficient (ICC). Internal consistency between the subscales was analysed by Cronbach's Alpha. Responsiveness was tested if the first APS score was positive for pain. 'Before' and 'after' sum scores were compared by paired t-test.

Results: We found poor agreement between APS and VRS (k=0.42). The inter-rater reliability was good (ICC=0.84). Cronbach's Alpha was 0.52 (fair agreement). In 66% of the patients, pain was observed and re-tested when an expected effect of analgesics had occurred. Of these, 88% reached a reduction on the APS sum-score (p<0.001).

Conclusion: Our assessment of the Danish version of APS shows that this pain assessment scale should be considered as qualified and usable in severely demented and non-communicative older patients admitted to a geriatric ward.