Objective

To assess differential item functioning (DIF) in an item pool measuring the mobility of hospitalized patients across educational, age, and gender groups.

Design

Measurement evaluation cohort study. Content experts generated DIF hypotheses to guide the interpretation. The graded response item response theory (IRT) model was used. Primary DIF tests were Wald statistics; sensitivity analyses were conducted using the IRT ordinal logistic regression procedure. Magnitude and impact were evaluated by examining group differences in expected item and scale score functions.

Setting

Hospital-based rehabilitation

Participants

2216 hospitalized patients

Main Outcome Measures

111 self-reported mobility items

Results

Two linking items among those used to set the metric across forms evidenced DIF for gender and age: ‘difficulty climbing stairs step-over-step without a handrail (alternating feet)’ and ‘difficulty climbing 3 to 5 steps without a handrail’. Conditional on the mobility state, the items were more difficult for women and older people (aged 65 and over). An additional 18 items were identified with DIF. Items with both high DIF magnitude and hypotheses related to age were difficulty: ‘crossing road at a 4-lane traffic light with curbs’; ‘jumping/landing on one leg’; ‘strenuous activities’; ‘descending 3-5 steps with no handrail’. Although DIF of higher magnitude was observed for several items, the scale-level impact was relatively small and the exposure rate for the most problematic items was low (0.35, 0.27 and 0.20).

Conclusions

This was the first study to evaluate measurement equivalence of the hospital-based rehabilitation mobility item bank. Although 20 items evidenced high magnitude DIF, five related to stairs, the scale-level impact was minimal; however, it is recommended that such items be avoided in the development of short-form measures. No items with salient DIF were removed from calibrations, supporting the use of the item bank across groups differing in education, age, and gender. The bank may thus be useful to assist clinical assessment and decision-making regarding risk for specific mobility restrictions at discharge as well as identifying mobility-related functions targeted for post- discharge interventions. Additionally, with the goal of avoiding long and burdensome assessments for patients and clinical staff; these results could be informative for those using the item bank to construct short forms.

中文翻译：

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使用差异项目功能分析检查急性护理 MCAT (FAMCAT) 流动性项目库中功能评估的测量等效性

客观的

评估项目池中的差异项目功能 (DIF)，以衡量住院患者在教育、年龄和性别群体中的流动性。

设计

测量评估队列研究。内容专家生成 DIF 假设来指导解释。使用分级反应项目反应理论（IRT）模型。初级 DIF 测试是 Wald 统计；使用 IRT 序数逻辑回归程序进行敏感性分析。通过检查预期项目和量表得分函数中的组差异来评估量级和影响。

环境

住院康复

参加者

2216 名住院患者

主要观察指标

111 个自我报告的流动性项目

结果

用于跨表格设置指标的两个关联项目证明了性别和年龄的 DIF：“在没有扶手的情况下逐步爬楼梯困难（双脚交替）”和“在没有扶手的情况下难以爬 3 到 5 步”。以行动状态为条件，女性和老年人（65 岁及以上）的项目难度更大。另有 18 个项目被识别为 DIF。具有高 DIF 大小和与年龄相关的假设的项目是困难的：“在有路缘的 4 车道交通信号灯处过马路”；“单腿跳跃/着陆”；“剧烈活动”；“在没有扶手的情况下下降 3-5 步”。尽管在几个项目中观察到更高量级的 DIF，但规模级影响相对较小，并且最有问题的项目的暴露率很低（0.35、0.27 和 0.20）。

结论

这是第一项评估基于医院的康复移动项目库的测量等效性的研究。尽管有 20 个项目证明了高强度 DIF，其中 5 个与楼梯有关，但规模级影响很小；但是，建议在制定简短措施时避免使用此类项目。没有从校准中删除具有显着 DIF 的项目，支持跨教育、年龄和性别不同的群体使用项目库。因此，该银行可能有助于协助临床评估和决策有关出院时特定行动限制的风险，以及确定针对出院后干预的行动相关功能。此外，为了避免对患者和临床工作人员进行冗长而繁重的评估；