Pathak A.1, Sharma S.1, Jensen M.2
1Kathmandu University School of Medical Sciences, Department of Physiotherapy, Dhulikhel, Nepal, 2University of Washington, Department of Rehabilitation Medicine, Seattle, United States
Background: A number of clinical guidelines, such as those of the American Pain Society, recommend routine assessment of pain. The most commonly used scales for assessing pain intensity include the Numerical Rating Scale (NRS), Visual Analogue Scale (VAS), Faces Pain Rating Scale Revised (FPS-R) and Verbal Rating Scale (VRS). Cultural and educational backgrounds likely influence one's ability to understand and express pain. Although the NRS is routinely used in Nepal based on recommendations from research in other populations, the validity and utility of the NRS, relative to other pain rating scales, has not yet been examined in samples of individuals with chronic pain from Nepal.
Purpose: The objectives of this study were to evaluate the utility and validity of different pain intensity rating scales in a Nepalese sample with musculoskeletal pain. Specifically, we sought to:
(1) determine which scale is most preferred by the Nepalese sample;
(2) compare relative rates of incorrect responses;
(3) evaluate if preference and error rates were influenced by age or education level; and
(4) evaluate the construct validity of each scale using factor analysis.
(1) determine which scale is most preferred by the Nepalese sample;
(2) compare relative rates of incorrect responses;
(3) evaluate if preference and error rates were influenced by age or education level; and
(4) evaluate the construct validity of each scale using factor analysis.
Methods: Two hundred and two participants from Nepal with musculoskeletal pain aged 18 years and older rated their average and worst pain intensity in the past week in all four scales. They then indicated the scale they most preferred, and their response to each scale was classified as correct or incorrect.
Results: The FPS-R was most preferred and the NRS was the least preferred scale. In addition, the NRS had the highest rate of incorrect responses. Age and education were associated with preference for the NRS, such that older and less educated participants were less likely to prefer NRS. Those with less education and older participants were also more likely to provide incorrect responses on all of the scales. All of the scales had adequate construct validity as measures of pain intensity.
Conclusion(s): Although the findings indicate that all four scales are valid as measures of pain intensity (for those who are able to provide correct responses to all scales), on the basis of preference and lower rates of incorrect responding, the FPS-R appears to have the most and the VRS the second most utility for assessing pain intensity in Nepalese adults with musculoskeletal pain.
Implications: The current practice of using NRS in clinical and research setting in Nepalese adults may only be appropriate for patients who have more education; the FPS-R and VRS appear to be more appropriate for use in individuals from Nepal who are older or who have less education. The consistent use of these scales would allow for more valid comparisons across Nepalese samples. In addition, pain researchers who wish to be able to compare their findings with those obtained from studies performed in other countries would do well to consider including pain intensity measures shown to be valid and useful across a variety of samples, such as the FPS-R, in order to maximize the opportunities for valid cross-study (and cross-cultural) comparisons.
Funding acknowledgements: None
Topic: Pain & pain management
Ethics approval: This study was approved by the Institutional Review Committee, Kathmandu University School of Medical Sciences, Nepal.
All authors, affiliations and abstracts have been published as submitted.
