title: Regional differences in screening for retinopathy of prematurity in infants born before 27 weeks of gestation in Sweden--the EXPRESS study.
abstract: OBJECTIVE
  The primary aim was to analyse regional incidences of retinopathy of prematurity (ROP) and frequencies of treatment and their relation to perinatal risk factors during a 3-year period. A secondary aim was to study adherence to the study screening protocol in the different regions.
  
  
  METHODS
  A population-based study of neonatal morbidity in extremely preterm infants in Sweden (EXPRESS) was performed during 2004-2007. Screening for ROP was to start at postnatal age 5 weeks and to continue weekly until the retina was completely vascularized or until regression of ROP. Logistic regression analyses were used for evaluation of differences in incidence of Any ROP, ROP 3 or more and ROP Type 1 between the seven regions of the country.
  
  
  RESULTS
  The regional incidence of ROP varied between 54% and 92% for Any ROP, between 25% and 43% for ROP stage 3 or more and between 8% and 23% of infants with ROP Type 1, all of whom were treated. There was no significant difference between the regions regarding ROP Type 1, even when adjusting for known risk factors for ROP.
  
  
  CONCLUSIONS
  The heterogeneity between the regions regarding the incidence of ROP was reduced with increasing severity of ROP, and there was no heterogeneity regarding frequency of treatment for ROP, which is the most important issue for the children. We cannot exclude observer bias regarding mild ROP and ROP stage 3 in this study.
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, SwedenDepartment of Ophthalmology, Trondheim University Hospital, Trondheim, NorwayTornbladsinstitutet, Lund University, Lund, SwedenSection of Pediatric Ophthalmology, The Queen Silvia Children's Hospital, Sahlgrenska Academy, University of Gothenburg, Gothenburg, SwedenDepartment of Ophthalmology, Linköping University, Linköping, SwedenDepartment of Clinical Sciences, Ophthalmology, Umeå University, Umeå, SwedenDepartment of Ophthalmology, Lund University Hospital, Lund, SwedenSection of Pediatric Ophthalmology, St. Erik's Eye Hospital, Stockholm, Sweden.
authors.forename: Dordi
authors.initials: D
authors.lastname: Austeng
authors.forename: Karin
authors.initials: K
authors.lastname: Källen
authors.forename: Ann
authors.initials: A
authors.lastname: Hellström
authors.forename: Peter
authors.initials: P
authors.lastname: Jakobsson
authors.forename: Pia
authors.initials: P
authors.lastname: Lundgren
authors.forename: Kristina
authors.initials: K
authors.lastname: Tornqvist
authors.forename: Agneta
authors.initials: A
authors.lastname: Wallin
authors.forename: Gerd
authors.initials: G
authors.lastname: Holmström
mesh_terms: D001724:Birth Weight; D005865:Gestational Age; D006801:Humans; D015994:Incidence; D052577:Infant, Extremely Low Birth Weight; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D015997:Neonatal Screening; D016017:Odds Ratio; D012178:Retinopathy of Prematurity / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D015351:Vision Screening
keywords: extremely preterm; population-based; retinopathy of prematurity; screening, observer bias