title: [Limitations of case-mix systems in primary care: comparison of the severity of patients in community hospitals and health care centers in the United States].
abstract: OBJECTIVE
  The aim was to show the limitations of the case-mix "based on attendance", which take into account neither the seriousness of the diagnoses nor the comorbidity.
  
  
  METHODS
  A crossover descriptive study of a retrospective nature.
  
  
  METHODS
  In New York, in two centres located in the Hispanic community of Upper Manhattan and a third in the Presbyterian Hospital.
  
  
  METHODS
  During 1991, 225 patients were studied: 150 attended in the hospital PCC and 75 in the non-hospital PCCs. A simple random sampling of the list of patients attended was performed.
  
  
  METHODS
  The seriousness of the conditions of the patients attended in the two different types of PCC was compared through the Duke Severity of Illness Scale (DUSOI), a patient-based case-mix which assesses the level of seriousness of each individual diagnosis and the comorbidity linked to the diagnoses grouped together.
  
  
  RESULTS
  Significant differences between the seriousness of the conditions of the patients in the two sub-samples were found when comparison by means of bivariant analysis was performed. Scoring on the Severity Scale was significantly higher for those attending hospital (65.5 and 55.1 respectively).
  
  
  CONCLUSIONS
  Patient classification systems based on the reasons for attendance underestimate the seriousness of the condition. A case-mix in which the patient is the unit of analysis needs to be developed.
authors.affiliation: CAP Santa Perpétua de Mogoda, Barcelona.
authors.forename: M J
authors.initials: MJ
authors.lastname: Fernández de Sanmamed
authors.forename: O
authors.initials: O
authors.lastname: Fein
authors.forename: A
authors.initials: A
authors.lastname: Morrison
authors.forename: E
authors.initials: E
authors.lastname: Moy
mesh_terms: D003153:Community Health Services / Q000706:statistics & numerical data*; D003953:Diagnosis-Related Groups / Q000706:statistics & numerical data*; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D009518:New York / Q000453:epidemiology; D012720:Severity of Illness Index
vernacular_title: Limitaciones de los sistemas case-mix en atencion primaria: comparación de la gravedad de los pacientes atendidos en un centro ubicado en el hospital y dos centros extrahospitalarios en EE.UU.