title: Socioeconomic deprivation and hospital length of stay: a new approach using area-based socioeconomic indicators in multilevel models.
abstract: BACKGROUND
  Socioeconomic deprivation is not easily measurable in hospital information systems. However, its identification is essential, as it is associated with morbidity and hospital length of stay (LOS). We aimed at studying the feasibility of using routinely recorded individual and area-based socioeconomic indicators, and assessing their relation with LOS.
  
  
  METHODS
  In a cross-sectional study we collected area-based socioeconomic deprivation indicators from French census databases and individual ones from the 2009 medical and administrative databases of a French referral maternity hospital. The principal outcome was the LOS for delivery. Individual level socioeconomic deprivation indicators included preferential insurance scheme (health insurance allocated to poor persons). Nine area-based socioeconomic deprivation indicators were aggregated at the census tract and commune levels. The relation between socioeconomic deprivation and LOS was studied using multilevel models. The well-documented relation between socioeconomic deprivation and preterm delivery was firstly studied in these models as a validation step.
  
  
  RESULTS
  The linkage between aggregated and individual data was possible for the 3471 women included. The median LOS was 5 days. In multivariable analysis adjusted for age (P=0.02), twinning (P=0.0001), delivery mode (P<0.0001), drug addiction (P<0.0001), diagnosis-related group severity level (P<0.0001), and unemployment rate (P=0.002) were associated with an increased LOS.
  
  
  CONCLUSIONS
  Identifying deprived patients in hospital databases using routinely collected area-based indicators is feasible. The relation of these latter with LOS is consistent with previous studies. Further multicenter investigations are needed to confirm the interest of using such indicators for cost and morbidity predictions.
authors.affiliation: Department of Biostatistics, Regional Maternity Hospital, Nancy, France. v.coevoet@maternite.chu-nancy.fr
authors.forename: Vincent
authors.initials: V
authors.lastname: Coevoet
authors.forename: Jeanne
authors.initials: J
authors.lastname: Fresson
authors.forename: Rachel
authors.initials: R
authors.lastname: Vieux
authors.forename: Nicolas
authors.initials: N
authors.lastname: Jay
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D003953:Diagnosis-Related Groups; D005240:Feasibility Studies; D005260:Female; D005602:France; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data*; D008507:Medically Underserved Area; D011203:Poverty; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth; D012307:Risk Factors; D012923:Social Class; D012959:Socioeconomic Factors