Carreon Leah Y, Bratcher Kelly R, Das Nandita, Nienhuis Jacob B, Glassman Steven D
Norton Leatherman Spine Center, Louisville, Kentucky.
J Neurosurg Spine. 2014 Sep;21(3):394-9. doi: 10.3171/2014.5.SPINE13570. Epub 2014 Jun 6.
The Neck Disability Index (NDI) and numeric rating scales (0 to 10) for neck pain and arm pain are widely used cervical spine disease-specific measures. Recent studies have shown that there is a strong relationship between the SF-6D and the NDI such that using a simple linear regression allows for the estimation of an SF-6D value from the NDI alone. Due to ease of administration and scoring, the EQ-5D is increasingly being used as a measure of utility in the clinical setting. The purpose of this study is to determine if the EQ-5D values can be estimated from commonly available cervical spine disease-specific health-related quality of life measures, much like the SF-6D.
The EQ-5D, NDI, neck pain score, and arm pain score were prospectively collected in 3732 patients who presented to the authors' clinic with degenerative cervical spine disorders. Correlation coefficients for paired observations from multiple time points between the NDI, neck pain and arm pain scores, and EQ-5D were determined. Regression models were built to estimate the EQ-5D values from the NDI, neck pain, and arm pain scores.
The mean age of the 3732 patients was 53.3 ± 12.2 years, and 43% were male. Correlations between the EQ-5D and the NDI, neck pain score, and arm pain score were statistically significant (p < 0.0001), with correlation coefficients of -0.77, -0.62, and -0.50, respectively. The regression equation 0.98947 + (-0.00705 × NDI) + (-0.00875 × arm pain score) + (-0.00877 × neck pain score) to predict EQ-5D had an R-square of 0.62 and a root mean square error (RMSE) of 0.146. The model using NDI alone had an R-square of 0.59 and a RMSE of 0.150. The model using the individual NDI items had an R-square of 0.46 and an RMSE of 0.172. The correlation coefficient between the observed and estimated EQ-5D scores was 0.79. There was no statistically significant difference between the actual EQ-5D score (0.603 ± 0.235) and the estimated EQ-5D score (0.603 ± 0.185) using the NDI, neck pain score, and arm pain score regression model. However, rounding off the coefficients to fewer than 5 decimal places produced less accurate results.
The regression model estimating the EQ-5D from the NDI, neck pain score, and arm pain score accounted for 60% of the variability of the EQ-5D with a relatively large RMSE. This regression model may not be sufficient to accurately or reliably estimate actual EQ-5D values.
颈部功能障碍指数（NDI）以及颈部疼痛和手臂疼痛的数字评分量表（0至10）是广泛使用的针对颈椎病的测量方法。最近的研究表明，SF-6D与NDI之间存在很强的关系，以至于使用简单线性回归仅根据NDI就能估计SF-6D值。由于易于实施和评分，EQ-5D越来越多地被用作临床环境中的效用测量指标。本研究的目的是确定是否可以像SF-6D那样，从常用的针对颈椎病的特定健康相关生活质量测量指标中估计EQ-5D值。
前瞻性收集了3732例因退行性颈椎病到作者诊所就诊的患者的EQ-5D、NDI、颈部疼痛评分和手臂疼痛评分。确定了NDI、颈部疼痛和手臂疼痛评分与EQ-5D在多个时间点的配对观察的相关系数。建立回归模型以根据NDI、颈部疼痛和手臂疼痛评分估计EQ-5D值。
3732例患者的平均年龄为53.3±12.2岁，43%为男性。EQ-5D与NDI、颈部疼痛评分和手臂疼痛评分之间的相关性具有统计学意义（p<0.0001），相关系数分别为-0.77、-0.62和-0.50。预测EQ-5D的回归方程0.98947+（-0.00705×NDI）+（-0.00875×手臂疼痛评分）+（-0.00877×颈部疼痛评分）的决定系数R²为0.62，均方根误差（RMSE）为0.146。仅使用NDI的模型的R²为0.59，RMSE为0.150。使用NDI各个项目的模型的R²为0.46，RMSE为0.172。观察到的和估计的EQ-5D评分之间的相关系数为0.79。使用NDI、颈部疼痛评分和手臂疼痛评分回归模型得出的实际EQ-5D评分（0.603±0.235）与估计的EQ-5D评分（0.603±0.185）之间没有统计学上的显著差异。然而，将系数舍入到少于5位小数会产生不太准确的结果。
根据NDI、颈部疼痛评分和手臂疼痛评分估计EQ-5D的回归模型解释了EQ-5D变异性的60%，但RMSE相对较大。该回归模型可能不足以准确或可靠地估计实际EQ-5D值。
