Smallest Detectable Change of the Knowledge and Attitudes of Pain in a High-Presenteeism Population: Female Teleworkers with Chronic Neck/Shoulder Stiffness

Background Pain Science Education (PSE) aims to improve patients’ understanding of pain based on modern pain science, empowering informed care choices and supporting better health outcomes and has demonstrated effectiveness in chronic musculoskeletal conditions. The Knowledge and Attitudes of Pain (KNAP) questionnaire was developed to assess the knowledge and attitudes about pain science in physical therapy students undergoing PSE. In 2022, a Japanese-language version was created that is comprehensible to university students without specialized knowledge of pain. The KNAP is expected to assess changes in patients’ knowledge of pain science and attitudes toward pain among those receiving PSE, but its measurement error in patient populations remains unclear. This study aimed to determine the smallest detectable change (SDC) of the Japanese KNAP among female teleworkers with chronic neck/shoulder stiffness, a population with high levels of presenteeism. Methodology This test-retest reliability study was conducted alongside a randomized controlled trial involving female teleworkers with presenteeism related to neck/shoulder stiffness. Participants who completed the final one-year follow-up and who still had neck/shoulder stiffness were invited. The KNAP was administered via a web-based survey twice, with a one-week interval. The SDC was calculated using the intraclass correlation coefficient. Results A total of 101 participants completed two surveys. The mean KNAP total score was 75.6 (standard deviation (SD) 3.7). The SDC was 6.5. Conclusion The KNAP demonstrated a smallest detectable change of 6.5 points in female teleworkers with chronic neck/shoulder stiffness, indicating the threshold for changes beyond measurement error at the individual level. This finding contributes to the interpretability of the KNAP and may assist in evaluating changes over time, although the clinical importance of such changes remains to be established.