A comparison of three self-report pain scales in Sri Lankan children

Abstract

Background: Many self-report pain scales are available to assess the intensity of pain reported by children. There is hardly any research to compare their validity in Sri Lankan children. Objective: To compare 3 self-report pain scales viz. FACES Pain Scale (FPS), Numeric Pain Rating Scale (NRS) and Verbal Pain Rating Scale (VRS). Method: The study population comprised children 4- 12 years old who presented to the paediatric ward and clinic of Ampara General Hospital with a complaint of pain from July 2012 to June 2013. Each child graded the pain intensity on the three pain scales introduced in random order by a trained investigator and rated the most easily understood scale. The investigator was asked to rate the most easily explainable scale in the individual case. The scales were ranked according to internal consistency, child preference and investigator preference. Results: There were 152 children aged between 4-12 years who presented to the paediatric ward and clinic of Ampara General Hospital with a complaint of pain during the study period. The correlations between FPS/NRS, FPS/VRS and NRS/VRS were 0.82, 0.73 and 0.73 respectively, all with p<0.001, indicating moderate to high correlation and measuring the same construct. The Cronbach alpha was 0.9021 indicating that the internal consistency of these three scales was very high. The Bland-Altman analysis showed limits of agreement of FPS/ NRS, FPS/VRS and NRS/VRS to be -3.2 to +3.1, -3.3 to +4.4 and -3.3 to +4.4 respectively. There was no significant difference between young (4-7) and old (8-12) age group children rating their pain within and between the three pain scales. The FPS ranked best followed by the VRS and NRS. Conclusions: The reliability of all three pain scales in terms of correlation and internal consistency is moderate to high in Sri Lankan children. The FPS is recommended since it is easily understood by children and because of its easy administration and favourable internal consistency.