MCID of 6 commonly-used performance tests in patients with chronic musculoskeletal pain

Background Functional tests are widely used to measure performance in patients with chronic musculoskeletal pain. Our objective was to determine the Minimal Clinically Important Differences (MCID) for the 6-minute walk test (6MWT), the Steep Ramp Test (SRT), the 1-minute stair climbing test (1MSCT), the sit-to-stand test (STS), the Jamar dynamometer test (JAM) and the lumbar Progressive Isoinertial Lifting Evaluation (PILE) in chronic musculoskeletal pain patients. Methods A single-center prospective observational study was conducted in a rehabilitation center. Patients with upper-limb, lower-limb or neck/back lesions were included over a period of 21 months. The anchor-based, distribution-based and opinion-based approaches were used to determine the MCIDs. Results 838 chronic musculoskeletal pain patients were included. The estimation method and the lesion location had a significant influence on the results. MCIDs were estimated at +75m and +62m for the 6MWT (lower-limb and neck/back lesions, respectively), +18 steps and +19 steps for the 1MSCT (lower-limb and neck/back lesions, respectively) and +6kg for the JAM. The anchor-based method could not provide valid estimations for the three other scales, but distribution and opinion-based methods provided rough values of MCIDs for the SRT (+44w to +61w), the STS (-6 sec to -9 sec) and the PILE (+4kg to +7kg). Conclusion The above MCID estimations for the 6MWT, 1MSCT and JAM can be used in chronic musculoskeletal pain patients participating in vocational multidisciplinary rehabilitation programs or in therapeutic trials. The use of specific anchors might give better estimations of MCIDs for the three other scales in future research.

背景：功能测试被广泛应用于慢性肌肉骨骼疼痛患者的运动功能评估。本研究旨在明确慢性肌肉骨骼疼痛患者的六项测试的最小临床重要差异（Minimal Clinically Important Differences, MCID），具体包括6分钟步行试验（6-minute walk test, 6MWT）、斜坡爬坡试验（Steep Ramp Test, SRT）、1分钟爬楼梯试验（1-minute stair climbing test, 1MSCT）、坐站试验（sit-to-stand test, STS）、贾玛测力计测试（Jamar dynamometer test, JAM）以及腰椎渐进等惯量抬举评估（lumbar Progressive Isoinertial Lifting Evaluation, PILE）。

方法：本研究在某康复中心开展单中心前瞻性观察研究，纳入周期为21个月，研究对象为上肢、下肢或颈背部病变的慢性肌肉骨骼疼痛患者。本研究采用锚定法、分布法及专家意见法三种方式确定最小临床重要差异。

结果：本研究共纳入838例慢性肌肉骨骼疼痛患者。估算方法与病变部位对研究结果存在显著影响。其中6MWT的最小临床重要差异分别为下肢病变患者+75米、颈背部病变患者+62米；1MSCT分别为下肢病变患者+18步、颈背部病变患者+19步；JAM则为+6千克。锚定法无法为其余三项量表提供有效估算值，但分布法与专家意见法可得出SRT的MCID粗略值为+44w至+61w，STS为-6秒至-9秒，PILE为+4kg至+7kg。

结论：本次得出的6MWT、1MSCT及JAM的最小临床重要差异估算值，可应用于参与职业性多学科康复项目或治疗性临床试验的慢性肌肉骨骼疼痛患者。未来研究中若采用针对性锚定法，或可为其余三项量表提供更精准的最小临床重要差异估算结果。