Abstract
Purpose: :
To determine if a predictive model of risk for threshold or severe prethreshold retinopathy of prematurity (ROP) warranting surgery (hereafter ROP warranting surgery) can be used to select low–risk infants for alternative screening protocols that reduce eye examinations without excessive delay to the detection of ROP warranting surgery.
Methods: :
This is a retrospective chart review of 299 infants (596 eyes with adequate eye examinations) 401–1250 g at birth admitted to a level 3 NICU from 1998 to 2003. We used a previously developed multivariate model of risk with independent predictive variables of birth weight, gestational age, multiple birth, race, gender, and CRIBSUB (Clinical Risk Index for Babies Subscore). Outcome variable was ROP warranting surgery. This model has high predictive accuracy by receiver operating characteristics (area under the curve = 0.892). Using a probability of ≥ 0.15 as the threshold for high risk, the specificity and sensitivity of this model were 83.4% and 81.8%, respectively. Three alternative lower–frequency screening protocols for low–risk infants were simulated: 1) every 3 wks after the first examination [q3], 2) first examination at 35 wks postmenstrual age (PMA) then every 2 wks [35q2], or 3) first examination at 35 wks PMA then every 3 wks [35q3]. Screening reverts to the standard screening protocol (SSP), based on current screening recommendations for the United States, when prethreshold ROP, vascularization into zone 3, or adequate regression of ROP occur. Savings in eye examinations and delay to detection of ROP warranting surgery due to the alternative screening protocols were calculated by comparison with 1) the actual sequence of eye examinations or 2) the ideal sequence of eye examinations that should have been performed using SSP.
Results: :
Overall savings in eye examinations was 14% to 16% for the best alternative screening protocol (35q3). The percentage of low–risk infants with on–time detection of ROP warranting surgery was 100%.
Conclusions: :
A predictive model of risk combined with an alternative lower–frequency screening protocol can safely reduce ROP examinations for premature infants ≤ 1250 g. Potential benefits include cost–savings and reduced exposure of premature infants to the risks associated with examinations. Before changing current screening recommendations, these findings would need to be confirmed in studies that account for possible center and physician variability in disease risk and screening methods.
Keywords: retinopathy of prematurity • clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: health care delivery/economics/manpower