title: Increased survival among lower-birthweight children in Southern Brazil.
abstract: OBJECTIVE
  To analyze factors associated with survival in the first year of life.
  
  
  METHODS
  A historical cohort study was carried out using data from live birth and mortality information systems, including 90,153 live birth records and 1,053 records of death before age one year in hospitals in the cities of Florianópolis and São José, Southern Brazil, between 1999 and 2006. Survival curves were estimated (Kaplan-Meier) for birthweight categories, date of birth (four-year periods), and type of maternity. Proportional hazard ratios for mortality were calculated using Cox regression.
  
  
  RESULTS
  Survival (98.8%) did not change among all birthweight categories, but increased among babies born weighing under 2,000 g (77.7% to 81.2%, p=0.029), between 1999-2002 and 2003-2006. There was an increase in the proportion of babies under 2,000 g in the second period. Type of hospital was significantly associated with probability of survival.
  
  
  CONCLUSIONS
  Probability of survival is higher among babies born in private hospitals and in the teaching hospital in all birthweight categories combined and for babies born weighing under 2,000 g. Survival among the latter increased in the most recent period. However, the infant mortality rate did not change between the two periods given the increase in the prevalence of children with ligther birth weight.
authors.affiliation: Departamento de Pediatria, Centro de Ciências da Saúde, Universidade Federal de Santa Catarina, Florianópolis, SC, Brasil. ceapinheiro1@gmail.com
authors.forename: Carlos Eduardo Andrade
authors.initials: CE
authors.lastname: Pinheiro
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Peres
authors.forename: Eleonora
authors.initials: E
authors.lastname: D' Orsi
mesh_terms: D001938:Brazil / Q000453:epidemiology; D015331:Cohort Studies; D006771:Hospitals, Maternity / Q000706:statistics & numerical data; D016304:Hospitals, Private / Q000706:statistics & numerical data; D006779:Hospitals, Public / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D007226:Infant Mortality / Q000639:trends*; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D015996:Survival Rate