Predicting respiratory distress syndrome using gestational age and fetal lung maturity by fluorescent polarization

Objective This study was undertaken to design a predictive model for assessing the risk of developing respiratory distress syndrome (RDS) by using gestational age (GA) and results from a quantitative fluorescence polarization-based fetal lung maturity assay (TDx FLM II). Study design The study populations from the 3 largest published studies analyzing the association between TDx-FLM II and the development of RDS were combined for this analysis. A total of 509 patients were included in this study; 57 gave birth to infants who had RDS develop, and 452 gave birth to infants who were unaffected. Logistic regression analysis was used to model the odds of RDS as a function of GA, TDx FLM II ratio, and study site. Results The absolute and relative risks of an infant having RDS develop as a function of GA and TDx FLM II were calculated. The odds of RDS decrease 31% for each increasing week of GA and decrease 67% for each 10 mg/g increase in the TDx FLM II ratio. GA-specific TDx FLM II cutoffs are provided for sensitivities between 84% and 100%. The bias-adjusted area under the receiver-operating characteristic curve for the classification of RDS, based on GA and TDx FLM II ratio, was 0.957 with the use of the logistic model. Conclusion The incorporation of GA into the evaluation of fetal lung monitoring allows for individualized, GA-specific risk assessment and provides GA-specific cutoffs with increased specificity.