Department of Community Health Sciences & O'Brien Institute for Public Health, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada.
Department of Clinical Neurosciences & Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
Qual Life Res. 2024 Dec;33(12):3409-3419. doi: 10.1007/s11136-024-03782-1. Epub 2024 Sep 9.
Patient-reported outcome measures (PROMs) such as the Neurological Disorders Depression Inventory in Epilepsy (NDDI-E), a 6-item epilepsy-specific PROM, is used to screen for major depressive disorder symptoms for patients with epilepsy (PWE). The validity and interpretation of PROMs can be affected by differential item functioning (DIF), which occurs when subgroups of patients with the same underlying health status respond to and interpret questions about their health status differently. This study aims to determine whether NDDI-E items exhibit DIF and to identify subgroups of PWE that exhibit DIF in NDDI-E items.
Data were from the Calgary Comprehensive Epilepsy Program database, a clinical registry of adult PWE in Calgary, Canada. A tree-based partial credit model based on recursive partitioning (PCTree) was used to identify subgroups that exhibit DIF on NDDI-E items using patients' characteristics as covariates. Differences in the identified subgroups were characterized using multinomial logistic regression.
Of the 1,576 patients in this cohort, 806 (51.1%) were female, and the median age was 38.0 years. PCTree identified four patient subgroups defined by employment status, age, and sex. Subgroup 1 were unemployed patients ≤ 26 years old, subgroup 2 were unemployed patients > 26 years, subgroup 3 were employed females, while subgroup 4 were employed male patients. The subgroups exhibited significant differences on education level, comorbidity index scores, marital status, type of epilepsy, and driving status.
PWE differed in their interpretation and responses to questions about their depression symptoms, and these differences were a function of sociodemographic and clinical characteristics.
患者报告的结局测量（PROMs），如癫痫患者的神经障碍抑郁量表（NDDI-E），一种 6 项癫痫特有的 PROM，用于筛查癫痫患者（PWE）的重度抑郁障碍症状。PROMs 的有效性和解释可能受到差异项目功能（DIF）的影响，当具有相同潜在健康状况的患者亚组对其健康状况问题的反应和解释不同时，就会出现 DIF。本研究旨在确定 NDDI-E 项目是否存在 DIF，并确定 NDDI-E 项目中存在 DIF 的 PWE 亚组。
数据来自加拿大卡尔加里综合癫痫计划数据库，这是一个成人 PWE 的临床登记处。使用基于递归分区的树状部分信用模型（PCTree），根据患者的特征作为协变量，识别在 NDDI-E 项目上存在 DIF 的亚组。使用多项逻辑回归来描述所识别的亚组之间的差异。
在该队列的 1576 名患者中，806 名（51.1%）为女性，中位年龄为 38.0 岁。PCTree 确定了四个由就业状况、年龄和性别定义的患者亚组。亚组 1 为年龄≤26 岁且失业的患者，亚组 2 为年龄>26 岁且失业的患者，亚组 3 为就业女性，而亚组 4 为就业男性患者。这些亚组在教育水平、合并症指数评分、婚姻状况、癫痫类型和驾驶状况方面存在显著差异。
PWE 在他们对自己抑郁症状问题的解释和反应方面存在差异，这些差异是社会人口统计学和临床特征的函数。
