Department of Psychology, College of Science, The University of Texas, Arlington, TX 76019, USA.
Spine J. 2010 Apr;10(4):321-7. doi: 10.1016/j.spinee.2009.10.015.
Various methodologies have been used in attempting to elucidate a standard method for calculating minimal clinically important difference (MCID). A consensus-based decision (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials [IMMPACT] group) suggested a 30% reduction from baseline as a means to define the MCID of self-report back pain measures. Additionally, important psychometric issues need to be addressed regarding use of an independent measure of the same construct as an external criterion, instead of simply using another self-report measure, when using an anchor-based approach to MCID.
The purpose was to test the validity of recently published guidelines regarding MCID using self-report back pain measures and objective socioeconomic outcomes.
STUDY DESIGN/SETTING: This is a prospective study assessing change scores on commonly used spinal pain assessment measures in patients with chronic disabling occupational spinal disorders (CDOSDs) treated in a regional referral rehabilitation center performing interdisciplinary functional restoration.
The study consisted of consecutive cohort of patients (N=1,180) with CDOSDs completing a functional restoration program.
Self-report measures including the Oswestry Disability Index (ODI) and the physical component summary (PCS) and mental component summary (MCS) of the Short Form-36 (SF-36) obtained before and after treatment, were compared with objective socioeconomically relevant outcomes obtained 1 year after treatment (ie, work status and additional health-care utilization), that were the external criteria for evaluating MCID.
Pre- to posttreatment improvement was calculated separately for each measure, and subjects were divided into two groups based on the change in scores relative to baseline: 30% or greater versus less than 30% improvement. One-year posttreatment objective socioeconomic outcomes were used as independent external criteria relevant to the CDOSD population. This population is often studied as the most costly and problematic cohort in spine care.
The ODI and SF-36 MCS were not associated with any of the objective 1-year outcomes used as external criteria. Reduced post-rehabilitation health-care utilization (based on the percentage of patients pursuing health care from a new provider) was weakly associated with 30% or greater improvement on the SF-36 PCS, relative to patients whose scores changed by less than 30% relative to baseline (17.0% vs. 21.1%). The same was true for the ODI and return-to-work.
When objective and independent criteria are used (socioeconomic outcomes) in a CDOSD cohort, the 30% improvement in the ODI and SF-36 may not be a valid MCID index. This replicates similar conclusions made by an independent research group using a distribution-based approach to MCID. The validity of the MCID concept rests on future research using objective external criteria. Moreover, there remains a question whether the term "important" in MCID can be unequivocally and operationally defined as a reliable construct.
为了阐明计算最小临床重要差异（MCID）的标准方法，已经使用了各种方法。一项基于共识的决策（临床试验方法、测量和疼痛评估倡议[IMMPACT]小组）建议，基线降低 30%是定义自我报告背痛测量的 MCID 的一种方法。此外，当使用锚定方法确定 MCID 时，需要解决使用同一结构的独立测量作为外部标准，而不仅仅是使用另一种自我报告测量的重要心理测量学问题。
本研究旨在使用自我报告的背痛测量和客观的社会经济结果来测试最近发表的 MCID 指南的有效性。
研究设计/地点：这是一项前瞻性研究，评估了在进行跨学科功能恢复的区域转诊康复中心接受治疗的慢性致残性职业性脊柱疾病（CDOSD）患者中，常用脊柱疼痛评估测量的变化分数。
该研究包括连续队列的 CDOSD 患者（N=1180），他们完成了功能恢复计划。
治疗前后获得的自我报告测量，包括 Oswestry 残疾指数（ODI）和 Short Form-36（SF-36）的物理成分综合评分（PCS）和心理成分综合评分（MCS），与治疗 1 年后获得的客观、与社会经济相关的结果（即工作状态和额外的医疗保健利用）进行了比较，这些结果是评估 MCID 的外部标准。
分别计算每个测量的治疗前后改善情况，并根据与基线相比的评分变化将受试者分为两组：改善 30%或更多与改善小于 30%。治疗 1 年后的客观社会经济结果被用作与 CDOSD 人群相关的独立外部标准。该人群通常被研究为脊柱护理中最昂贵和最成问题的队列。
当使用客观和独立的标准（社会经济结果）时，在 CDOSD 队列中，ODI 和 SF-36 改善 30%可能不是有效的 MCID 指标。这与使用基于分布的 MCID 方法的独立研究小组得出的类似结论相吻合。MCID 概念的有效性取决于未来使用客观外部标准的研究。此外，MCID 中“重要”一词是否可以明确且可操作地定义为可靠的结构仍然存在疑问。
