Comparison of three acute colic pain scales: Reliability, validity and usability.

This research involves comparing the reliability, validity, and usability of three scales used for measuring acute abdominal pain in horses. The results demonstrated that while all three scales had similar usability and other validity measurements, the equine acute abdominal pain scale (EAAPS) showed superior reliability. However, a scale described by Mair and Smith in 2005 had better endorsement from experts.

Study Aim and Methodology

• This study aimed to compare the reliability, validity, and usability of three scales used for assessing the severity of acute abdominal pain, or colic, in horses. The scales were: the equine acute abdominal pain scale (EAAPS), a scale developed by Mair and Smith in 2005 (M and S), and a numerical rating scale (NRS).
• The study method involved the use of forty short films with 35 showing horses with colic and 5 as control horses. These images were randomly shown to 46 equine veterinarians from different countries.
• To ensure diverse responses, the participating veterinarians were divided into three groups to use each of the three scales. For evaluating the repeatability of the scale usage (intra-observer reliability), five randomly selected films were presented twice.

Reliability and Validity Results

• The EAAPS scale showed a higher inter-observer reliability with an intraclass correlation (ICC) of 0.86, which was better than the 0.68 for M and S and 0.71 for NRS. This means that the EAAPS could more consistently distinguish between severe and non-severe colic pain cases across different observers. The intra-observer reliability for EAAPS was also higher, indicating repeatability when used by the same observer over time.
• Validity is the ability of the scale to measure what it is intended to measure. Here, the EAAPS, M and S, and NRS showed no significant difference in convergent validity (correlation to other valid scales), extreme group validity (ability to distinguish between extreme cases) or predictive validity (accuracy in predicting outcomes).

Usability and Face Validity Results

• The time taken to score the films (usability) was found to be not significantly different across the three scales. This reflects that in terms of speed and ease of use, all three scales were comparable.
• Face validity refers to the degree to which a measurement or test appears effective in terms of its stated aims. In this case, the M and S scale had better endorsement by the expert participants, hence higher face validity. This points to acceptance and trust in this scale among the practitioners.

Conclusion

• Overall, the EAAPS showed superior reliability, indicating that it was consistent in measuring acute colic pain among different veterinarians and over repeated measurements by the same observer.
• However, for acceptance and trust among the veterinarians (as reflected by face validity), the M and S scale was superior.
• Usability of the scales and their performance on other validity measures were comparable, implying similar effectiveness in real-world settings.