Preference for different anchor descriptors on visual analogue scales among Japanese patients with chronic pain.

Context: Although many previous studies have examined the preference of patients for different pain measurement scales, preference for anchor descriptors has not been thoroughly discussed.

Objectives: To examine (1) the preferred end-phrases used in the VAS as anchor labels for Japanese patients with chronic pain, and (2) whether the preference differs according to factors such as age, sex, educational level, duration of pain, and pain intensity.

Methods: We performed an observational study in patients suffering from non-cancer chronic pain for more than 3 months at a pain center in Japan. The patients were asked to rate their pain intensity using four types of VAS that used the following different anchor descriptors: "worst pain" ("Worst"), "worst pain bearable" ("Bearable"), "worst pain imaginable" ("Imaginable"), and "worst pain you have ever experienced" ("Experienced"). They were also asked to rank the four scales according to ease of responding, and asked which descriptor best reflected their perceived pain.

Results: In total, 183 patients participated in the study. They consisted of 119 (65.0%) women and 64 (35.0%) men aged 18-84 years with the mean age of 56.9 years. "Experienced" was most preferred (69.8%), followed by "Bearable" (66.3%), "Worst" (48.8%), and "Imaginable" (16.9%). Factors such as age, sex, educational background, duration of pain, and pain intensity did not significantly affect the results. In 83.1% of patients, the preferred descriptor corresponded to the descriptor that best reflected patients' perceived pain.

Conclusion: The frequently used expression "worst pain imaginable" is considered to be difficult to understand for most patients. Widely preferred descriptors, such as "worst pain you have ever experienced" and "worst pain bearable", should be used when evaluating perceived pain. The preference of anchor descriptors was not significantly affected by the factors such as age, sex, educational level, duration of pain, and pain intensity.