Bronfort G, Bouter L M
Department of Research, Wolfe-Harris Center for Clinical Studies, 2501 West 84th Street, Bloomington, MN 55431, USA.
Pain. 1999 Nov;83(2):201-9. doi: 10.1016/s0304-3959(99)00103-7.
The objective of this study was to compare the responsiveness and assess the concurrent validity of two functional health status instruments, the Dartmouth COOP charts and the SF-36 in chronic low-back pain (CLBP) patients. The data came from 129 of 174 patients who participated in a randomized clinical trial of the therapeutic management of CLBP. Reliable and valid disease-specific outcomes, patient-rated low-back pain and disability, were used as external criteria (EC) to identify improved and non-improved patients. Unpaired t-statistics and receiver operating characteristic (ROC) curve calculations were used to quantify responsiveness. The two instruments had sufficient and very similar responsiveness using both EC. Comparisons between improved and non-improved patients for the COOP charts and SF-36, respectively, using pain as EC, yielded differences which translated into large effect sizes (0.8 and 0.7) (P=0.0008 and 0.003). Using disability as EC, differences of moderate effect size were found (0.5 and 0.6) (P=0.02 and 0.002). The ROC curve calculations using pain as EC resulted in areas under the curve of 0.76 (95% CI: 0.64, 0.88) for the COOP charts, and 0.74 (95% CI: 0.60, 0.88) for the SF-36. The corresponding areas using disability as EC were 0.67 (95% CI: 0.55, 0.79) and 0.72 (95% CI: 0.60, 0.84). The best cut-off point in both instruments for differentiating between improved and non-improved patients was approximately six percentage points. The constructs of functional health status, as reflected in the global scores of the two instruments, are highly correlated (r=0.82). Six of the instruments' nine dimensions are moderately to highly correlated (r=0.52 to 0.86), and the overall canonical correlation was high (R=0.9). In conclusion, both instruments seem equally suitable for use as outcome measures in clinical trials on CLBP. The COOP charts are faster to fill out and score.
本研究的目的是比较两种功能健康状况评估工具——达特茅斯COOP图表和SF-36在慢性下腰痛（CLBP）患者中的反应性，并评估其同时效度。数据来自174名参与CLBP治疗管理随机临床试验的患者中的129名。可靠且有效的疾病特异性结局、患者自评的下腰痛和残疾情况被用作外部标准（EC），以确定病情改善和未改善的患者。采用非配对t检验和受试者工作特征（ROC）曲线计算来量化反应性。使用两种外部标准时，这两种评估工具均具有足够且非常相似的反应性。分别以疼痛作为外部标准，比较COOP图表和SF-36中病情改善和未改善患者的情况，得出的差异转化为较大的效应量（0.8和0.7）（P=0.0008和0.003）。以残疾作为外部标准时，发现了中等效应量的差异（0.5和0.6）（P=0.02和0.002）。以疼痛作为外部标准进行的ROC曲线计算得出，COOP图表的曲线下面积为0.76（95%CI：0.64，0.88），SF-36的曲线下面积为0.74（95%CI：0.60，0.88）。以残疾作为外部标准时的相应面积分别为0.67（95%CI：0.55，0.79）和0.72（95%CI：故0.60，0.84）。两种评估工具区分病情改善和未改善患者的最佳临界点约为6个百分点。两种评估工具总体评分所反映的功能健康状况结构高度相关（r=0.82）。两种评估工具九个维度中的六个维度具有中度至高度相关性（r=0.52至0.86），总体典型相关性较高（R=0.9）。总之，在CLBP的临床试验中，这两种评估工具似乎同样适合用作结局指标。COOP图表填写和评分更快。
