To Örebro University

Purpose: To investigate whether recent Swedish guidelines for Retinopathy of Prematurity (ROP) screening, that is, a gestational age (GA) at birth of less than31weeks (w), are applicable in a new national cohort of prematurely born infants.

Methods: SWEDROP is a national register for ROP, initiated in 2006. The present paper reports on data from the register on various aspects of screening for ROP in infants born between 2010 and 2011 and compares the results with those for a previously published cohort born between 2008 and 2009. ResultsDuring the study period, 1744 infants were screened for ROP. Mean GA was 28.4w (22-31), and mean birth weight was 1239g (382-2615). Screening started at postnatal age (PNA) 5.4w (0.4-13.3) and postmenstrual age (PMA) 33.8 w (24.9-50.1) Mean number of examinations was 5.4 per infant (1-38). Mild (stages 1-2) and severe ( stage 3) ROP was found in 15.4% and 8.7%, respectively. Treatment was performed in 4.2% (73/1744) of the infants, but in none with a GA of 30weeks or more. The first treatment was performed at a mean PNA and PMA of 12.7 w (7.7-25.4) and 37.4 w (32.1-51.4), respectively.

Conclusions: Recently introduced new guidelines for ROP screening in Sweden remain applicable. Reassuringly, in infants born between 2010 and 2011, incidence of ROP, frequency and timing of treatment, frequency and timing of examinations and national coverage of ROP screening remained almost identical to those for a previous cohort from 2008 to 2009. The two SWEDROP cohorts provide a basis for discussion among Swedish ophthalmologists and neonatologists on the question of further lowering the upper screening limit with 1week.

Purpose: 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 5weeks 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.

Conclusion: 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.