Social deprivation among socio-economic contrasted french areas: Using item response theory analysis to assess differential item functioning of the EPICES questionnaire in stroke patients.

Adrien Guilloteau,Marie Laure Lalanne-Mistrih,Claire Bonithon-Kopp,Isabelle Fournel,Caroline Mislin-Tritsch,Annie Lannuzel,André Cabie,Christine Binquet,Emmanuelle Mimeau,Yannick Béjot,Devi Rochemont,Hervé Devilliers,Abderrahmane Bourredjem,Mathieu Nacher,Julien Joux,Young Dae Kwon

doi:10.1371/journal.pone.0230661

Abstract

BackgroundMultiple approaches have been proposed to measure low socio-economic status. In France the concept of precariousness, akin to social deprivation, was developed and is widely used. EPICES is a short questionnaire that was developed to measure this concept. This study aimed to evaluate Differential Item Functioning (DIF) in the EPICES questionnaire between contrasted areas: mainland France, French West Indies (FWI) and French Guiana (FG).MethodsThe population was taken from the INDIA study, which aimed to evaluate the impact of social inequalities on stroke characteristics and prognosis. Eligible people were patients referred to neurology or emergency departments for a suspicion of stroke. We assessed the DIF using hybrid ordinal logistic regression method, derived from item response theory.ResultsWe analysed 1 553 stroke patients, including 768 from FWI (49.5%), 289 from FG (18.6%) and 496 from mainland (31.9%). We identified five items with a moderate to large DIF in area comparisons: “meeting with a social worker”, “complementary health insurance”, “home-owning”, “financial difficulties” and “sport activities”. Correlation between EPICES score and the latent variable was strong (r = 0.84).ConclusionThis is the first attempt to assess the DIF of the EPICES score between different French populations. We found several items with DIF, which can be explained by individual interpretation or local context. However, the DIFs did not lead to a large difference between the latent variable and the EPICES score, which indicates that it can be used to assess precariousness and social deprivation between contrasted areas.

Highlights

Since the Second World War, socio-economic inequalities have shown a stable or rising trend between the wealthiest and the poorest populations, even in countries with a large welfare budget [1]
We identified five items with a moderate to large Differential Item Functioning (DIF) in area comparisons: “meeting with a social worker”, “complementary health insurance”, “home-owning”, “financial difficulties” and “sport activities”
We found several items with DIF, which can be explained by individual interpretation or local context

Summary

Introduction

Since the Second World War, socio-economic inequalities have shown a stable or rising trend between the wealthiest and the poorest populations, even in countries with a large welfare budget [1]. Lack of knowledge about disease and limited access to the health care system in the most disadvantaged have been mentioned to explain this relationship [3,4,5] These results demonstrate that taking into account the effect of social status or poverty is a truly critical issue in epidemiological studies [6]. The strong cultural taboo on revealing earnings in some countries is a caveat to the use of this approach in epidemiological studies [7]. This approach fails to account for the multidimensional aspects of poverty and its social dimension. This study aimed to evaluate Differential Item Functioning (DIF) in the EPICES questionnaire between contrasted areas: mainland France, French West Indies (FWI) and French Guiana (FG)

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Conclusion