title: [Geographical bias in the inhospital mortality estimated by the Hospital Morbidity Survey].
abstract: BACKGROUND
  The Hospital Morbidity Survey (EMH) includes, at the moment, 85% of hospitals and 90% of discharges, and is the only national data source that allows to deepen with information about diagnostics, gender or age, in the study of hospitals as place of death. This work aims to analyze the presence of inhospital mortality geographical biases in the EMH in relation to the sample universe represented by the Statistics of Health Establishments with Inpatient Regime (EESCRI).
  
  
  METHODS
  We compared, for each province in 2004, the EMH estimations for discharges, deaths and the percent of mortality with the data from the EESCRI, and adjusting one linear regression model for the number of deaths and a second model for the percent of mortality.
  
  
  RESULTS
  The EMH infraestimated the volume of discharges and deaths (-8.6% and -11.4%), but not the inhospital mortality rate (3.55% vs. 3.45%). In spite of the excellent correlation in the number of deaths, figures in the EMH are inferior to the EESCRI figures in most provinces, and in 13 provinces the discrepancies overcome the 20%. The percent of mortality showed discrepancies overcoming 20% in 9 provinces.
  
  
  CONCLUSIONS
  In 2004, the EMH infraestimates the discharges and deaths figures but, except for 9 provinces, there are not evidence of important biases in the percent of mortality.
authors.affiliation: Instituto Aragonés de Ciencias de la Salud, Zaragoza. jlibrero.iacs@aragon.es
authors.forename: Julián
authors.initials: J
authors.lastname: Librero
authors.forename: Salvador
authors.initials: S
authors.lastname: Peiró
authors.forename: Manuel
authors.initials: M
authors.lastname: Ridao-López
authors.forename: Enrique
authors.initials: E
authors.lastname: Bernal-Delgado
mesh_terms: D015982:Bias; D003625:Data Collection; D017052:Hospital Mortality; D006801:Humans; D016014:Linear Models; D013030:Spain