Validation of the Retinopathy of Prematurity Activity Scale (ROP-ActS) using retrospective clinical data.

Aldina Pivodic,Ann Hellström,Andreas Stahl,Lois E.H Smith,Staffan Nilsson

doi:10.1111/aos.14532

Abstract

Purpose:The International Neonatal Consortium recently published a proposed retinopathy of prematurity (ROP) activity scale intended for use in clinical trials after validation. The aim of this study was to validate the ROP activity scale (ROP-ActS) in a ROP screened cohort with protocol based collected data by evaluating the ability of the ROP-Act scores to predict ROP treatment. In addition, we aimed to evaluate the scale’s sensitivity characteristic of disease severity by studying association with gestational age (GA) in comparison with conventionally used ROP stage and zone.Methods:A cohort of 535 preterm infants with 3324 ROP examinations with an end-point of ROP treatment or end of screening in Gothenburg, Sweden, was included. Median GA was 28.1 weeks, 47.5% were girls, and 74 (13.8%) infants were treated for ROP. The validation was performed by estimating probabilities for ROP treatment, and by applying logistic and linear regression.Results:The original ROP-ActS was overall well-ordered with respect to ability to predict ROP treatment but could be improved by re-ordering score 3 (zone II stage 1) and 5 (zone III stage 3) based on our clinical cohort data. The modified ROP-ActS was superior to ROP stage and zone in the prediction analysis of ROP treatment. Modified ROP-ActS was more strongly related to GA than currently used ROP stage, but not zone.Conclusion:In the studied cohort, the modified ROP-ActS could better predict ROP treatment compared to ROP stage and zone. Retinopathy of Prematurity Activity Scale (ROP-ActS) had a superior sensitivity characteristic studied through association to GA than conventionally used ROP stage.

Highlights

The International Neonatal Consortium (INC) is focused on developing objective descriptors of all stages of retinopathy of prematurity (ROP) to discriminate effects of prevention and treatment
The developed ROP-ActS is based on a scale which included all theoretically possible combinations of the three currently used International Classification of Retinopathy of Prematurity (ICROP) determinants defining ROP severity (ICROP, 2005)
Retinopathy of Prematurity (ROP) stage, zone and status of plus disease were defined according to the International Classification of Retinopathy of Prematurity (ICROP, 2005)

Summary

Introduction

The International Neonatal Consortium (INC) is focused on developing objective descriptors of all stages of retinopathy of prematurity (ROP) to discriminate effects of prevention and treatment. Current studies apply the parameters stage, location (zone I-III), extent of proliferative disease and preplus/plus disease of the International Classification of Retinopathy of Prematurity (ICROP) for classification (ICROP, 2005). The developed ROP-ActS is based on a scale which included all theoretically possible combinations of the three currently used ICROP determinants defining ROP severity (zone, stage and presence of plus disease) (ICROP, 2005). These 23 combinations (range 0 [no ROP] to 22 [stage 5 ROP]) were originally ranked by ‘severity’ based on the clinical judgement of nine ROP experts (Smith et al, 2019). The ROP-ActS has not been evaluated on a clinical cohort

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