Mannion A F, Elfering A, Bago J, Pellise F, Vila-Casademunt A, Richner-Wunderlin S, Domingo-Sàbat M, Obeid I, Acaroglu E, Alanay A, Pérez-Grueso F S, Baldus C R, Carreon L Y, Bridwell K H, Glassman S D, Kleinstück F
Spine Center Division, Department of Teaching, Research and Development, Schulthess Klinik, Lengghalde 2, 8008, Zurich, Switzerland.
Institute for Psychology, University of Bern, Fabrikstrasse 8, 3012, Bern, Switzerland.
Eur Spine J. 2018 Mar;27(3):685-699. doi: 10.1007/s00586-017-5279-0. Epub 2017 Sep 2.
Designed for patients with adolescent idiopathic scoliosis, the SRS-22 is now widely used as an outcome instrument in patients with adult spinal deformity (ASD). No studies have confirmed the four-factor structure (pain, function, self-image, mental health) of the SRS-22 in ASD and under different contexts. Factorial invariance of an instrument over time and in different languages is essential to allow for precise interpretations of treatment success and comparisons across studies. This study sought to evaluate the invariance of the SRS-22 structure across different languages and sub-groups of ASD patients.
Confirmatory factor analysis was performed on the 20 non-management items of the SRS-22 with data from 245 American English-, 428 Spanish-, 229 Turkish-, 95 French-, and 195 German-speaking patients. Item loading invariance was compared across languages, age groups, etiologies, treatment groups, and assessment times. A separate sample of SRS-22 data from 772 American surgical patients with ASD was used for cross-validation.
The factor structure fitted significantly better to the proposed four-factor solution than to a unifactorial solution. However, items 14 (personal relationships), 15 (financial difficulties), and 17 (days off work) consistently showed weak item loading within their factors across all language versions and in both baseline and follow-up datasets. A trimmed SRS (16 non-management items) that used the four least problematic items in each of the four domains yielded better-fitting models across all languages, but equivalence was still not reached. With this shorter version there was equivalence of item loading with respect to treatment (surgery vs conservative), time of assessment (baseline vs 12 months follow-up), and etiology (degenerative vs idiopathic), but not age (< vs ≥50 years). All findings were confirmed in the cross-validation sample.
We recommend removal of the worst-fitting items from each of the four domains of the SRS-instrument (items 3, 14, 15, 17), together with adaptation and standardization of other items across language versions, to provide an improved version of the instrument with just 16 non-management items.
SRS-22专为青少年特发性脊柱侧凸患者设计，目前已广泛用作成人脊柱畸形（ASD）患者的疗效评估工具。尚无研究证实SRS-22在ASD患者及不同背景下的四因素结构（疼痛、功能、自我形象、心理健康）。一种工具在不同时间和不同语言中的因素不变性对于准确解释治疗效果以及跨研究比较至关重要。本研究旨在评估SRS-22结构在不同语言和ASD患者亚组中的不变性。
对SRS-22的20个非管理项目进行验证性因素分析，数据来自245名说美国英语、428名说西班牙语、229名说土耳其语、95名说法语和195名说德语的患者。比较了不同语言、年龄组、病因、治疗组和评估时间的项目负荷不变性。使用来自772名美国ASD手术患者的另一组SRS-22数据进行交叉验证。
与单因素解决方案相比，因素结构对提出的四因素解决方案的拟合效果明显更好。然而，项目14（人际关系）、15（经济困难）和17（误工天数）在所有语言版本以及基线和随访数据集中，在其因素内始终显示出较弱的项目负荷。一个精简版的SRS（16个非管理项目），在四个领域中使用了四个问题最少的项目，在所有语言中产生了拟合更好的模型，但仍未达到等效性。使用这个较短版本时，在治疗（手术与保守治疗）、评估时间（基线与12个月随访）和病因（退行性与特发性）方面，项目负荷具有等效性，但在年龄（<50岁与≥50岁）方面则不然。所有结果在交叉验证样本中均得到证实。
我们建议从SRS工具的四个领域中删除拟合最差的项目（项目3、14、15、17），并对其他项目进行跨语言版本的改编和标准化，以提供一个改进版的工具，仅包含16个非管理项目。
