The psychometric properties of Chinese pain intensity verbal rating scale

Background: This study investigates the validity and reliability of the Chinese pain intensity verbal rating scale (C-PIVRS). Methods: This is a correlational comparative study. Fifty Chinese adults were recruited by convenience. A pain source generator (precision pain source, PPS-3) was used to produce four levels of mechanical pain stimuli (350, 550, 750 and 950 g). The pain stimuli were applied to subjects' interphalangeal joints in random sequences to stimulate sensation of pain. The subjects then rated their pain intensity using both the C-PIVRS and the visual analog scale (VAS) for each stimulus. The pain scores obtained from the C-PIVRS were compared with the VAS for satisfactory level of reliability and validity. Test and re-test were applied to verify consistency between the two pain scales. Results: The test/re-test correlation coefficients between the two pain scales were r=0.92 (P<0.001) and r=0.91 (P < 0.001), respectively. This showed a good positive correlation. The intra-class correlation (ICC) ranged from 0.78 to 0.90, which indicated good reliability. In the factor analysis, a single factor emerged in each analysis. The first eigen values of each matrix were 3.42, 3.24, 3.17 and 3.29 for each level of pain stimulation. This indicated that both pain scales were assessing the same pain dimension. Conclusions: The two pain scales have a comparable level of reliability and validity for assessing pain intensity in Chinese adults.