Oude Voshaar Martijn A H, Schenk Olga, Ten Klooster Peter M, Vonkeman Harald E, Bernelot Moens Hein J, Boers Maarten, van de Laar Mart A F J
University of Twente, Enschede, The Netherlands.
University of Twente and Medisch Spectrum Twente, Enschede, The Netherlands.
Arthritis Care Res (Hoboken). 2016 Aug;68(8):1206-10. doi: 10.1002/acr.22793.
To further simplify the simple erosion narrowing score (SENS) by removing scored areas that contribute the least to its measurement precision according to analysis based on item response theory (IRT) and to compare the measurement performance of the simplified version to the original.
Baseline and 18-month data of the Combinatietherapie Bij Reumatoide Artritis (COBRA) trial were modeled using longitudinal IRT methodology. Measurement precision was evaluated across different levels of structural damage. SENS was further simplified by omitting the least reliably scored areas. Discriminant validity of SENS and its simplification were studied by comparing their ability to differentiate between the COBRA and sulfasalazine arms. Responsiveness was studied by comparing standardized change scores between versions.
SENS data showed good fit to the IRT model. Carpal and feet joints contributed the least statistical information to both erosion and joint space narrowing scores. Omitting the joints of the foot reduced measurement precision for the erosion score in cases with below-average levels of structural damage (relative efficiency compared with the original version ranged 35-59%). Omitting the carpal joints had minimal effect on precision (relative efficiency range 77-88%). Responsiveness of a simplified SENS without carpal joints closely approximated the original version (i.e., all Δ standardized change scores were ≤0.06). Discriminant validity was also similar between versions for both the erosion score (relative efficiency = 97%) and the SENS total score (relative efficiency = 84%).
Our results show that the carpal joints may be omitted from the SENS without notable repercussion for its measurement performance.
根据基于项目反应理论（IRT）的分析，去除对简单侵蚀狭窄评分（SENS）测量精度贡献最小的评分区域，以进一步简化该评分，并比较简化版与原版的测量性能。
采用纵向IRT方法对类风湿关节炎联合治疗（COBRA）试验的基线和18个月数据进行建模。在不同结构损伤水平上评估测量精度。通过省略评分最不可靠的区域进一步简化SENS。通过比较SENS及其简化版区分COBRA组和柳氮磺胺吡啶组的能力，研究其判别效度。通过比较不同版本之间的标准化变化分数研究反应度。
SENS数据很好地拟合了IRT模型。腕关节和足部关节对侵蚀和关节间隙狭窄评分的统计信息贡献最小。在结构损伤水平低于平均水平的病例中，省略足部关节会降低侵蚀评分的测量精度（与原版相比，相对效率范围为35%-59%）。省略腕关节对精度的影响最小（相对效率范围为77%-88%）。省略腕关节的简化SENS的反应度与原版非常接近（即所有Δ标准化变化分数均≤0.06）。侵蚀评分（相对效率=97%）和SENS总分（相对效率=84%）的不同版本之间的判别效度也相似。
我们的结果表明，从SENS中省略腕关节对其测量性能不会产生显著影响。
