Minimum Clinically Important Difference of the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire for Patients with Lumbar Spine Disease Undergoing Posterior Surgery by Generation

Introduction: Few studies have assessed the minimum clinically important difference (MCID) of each Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) domain. This study assessed MCIDs of JOABPEQ in patients with lumbar spine disease by generation. Methods: We evaluated the JOABPEQ score of 805 consecutive patients with lumbar spine disease undergoing posterior surgery preoperatively and 1 year postoperatively. MCIDs of each JOABPEQ domain were determined using anchor- and distribution-based methods according to age. A question based on the concept of a health transition item was used as the anchor for the MCID decision. Results: Overall, MCIDs of the JOABPEQ were 28.6 and 27.3 points for pain-related disorder and gait disturbance, respectively. The MCID for the lumbar spine dysfunction domain did not reach 0.6 over the area under the curve. Regarding the differences among generations, MCIDs of pain-related disorder and gait disturbance domains differed slightly between the elderly and middle-aged. The psychological disorder domain did not reflect clinically meaningful changes in the elderly. MCIDs of the social life disturbance domain decreased with age. Conclusions: Focusing on achieving the ideal responsiveness of patient-reported outcomes across generations, MCIDs of the pain-related disorder and gait disturbance domains may be valuable for patients, regardless of age, when adopting the JOABPEQ for patients with lumbar spine disease undergoing surgery. This study only evaluated cases that underwent posterior lumbar surgery. Future research will necessitate conducting surveys concerning the outcomes of various treatments for lumbar spine disease.