A Bedside Prediction-Scoring Model for Late-Onset Neonatal Sepsis

Abstract

OBJECTIVE:Insufficient tools for bedside prediction of late-onset neonatal sepsis (LNS) initiated this study. The objective was to develop and validate a simple prediction-scoring model for LNS defined as culture-proven sepsis occurring 72 hours after birth. METHODS:The study was performed at a university hospital in Bangkok. The derivation phase included medical records of 1870 neonates, randomly selected from 9347 records of neonates who had been hospitalized for >72 hours during 1998 to 2000, of which 1824 records were available. In all, 100 neonates were clinically suspected of sepsis and 17 had proven LNS. The validation phase included 73 neonates suspected of having sepsis during July 2002to June 2003 and 25 who had LNS. Weighted coefficients from Cox's proportional hazards model and receiveroperating-characteristic (ROC) curve analysis were used. RESULTS:The incidence density of LNS was 17/11355 (1.5/1000) person-days. A scoring model was developed and consisted of the following: hypotension (score 4), abnormal body temperature (score 3), respiratory insufficiency (score 2), neutrophil band form fraction >1% (score 2), platelet count <150 Â 10 3 /ml (score 2), and umbilical venous catheterization (1 to 7 or >7 days; score 2 or 4). The area under the ROC curves for prediction of LNS in a neonate suspected of sepsis in each of the two phases was 0.85 and 0.80, respectively (p ¼ 0.436). The mean probabilities of LNS were approximately 0.10 (low risk) for scores from 0 to 3; 0.50 (intermediate risk) for scores from 4 to 6; and 0.70 (high risk) for scores Z7. CONCLUSION:A simple prediction-scoring model for LNS was developed. Validation of the scores suggested good diagnostic performance.

External validation of bedside prediction score for diagnosis of late-onset neonatal sepsis

“…We found the performance of the LNS score determined by the AUC was acceptable and comparable with the internal validation study (n ¼ 73). 6 In contrast to the external validation study of the NOSEP score, 9 the AUC of the LNS score was comparable to the AUC of the original study, without any need for a modification of the LNS score. Hui et al 12 reported performance of procalcitonin testing for diagnosis of LNS in the same study population elsewhere.…”

“…6 The suggested cut-off value of 3 was based on test performance and the estimated probability. The observed prevalence of LNS in this study showed the same pattern of risk classified by the LNS score.…”

“…We developed a prediction tool for diagnosis of LNS, composed of four clinical parameters and two hematologic parameters as follows: hypotension, temperature abnormality, respiratory insufficiency, band count >1%, platelet count <150 000/ml 3 , and the use of umbilical venous catheters (UVC) between 1 and 7 days or >7 days. 6 In our original description, the LNS score yielded a good diagnostic performance with an area under the receiver-operating characteristics curve (AUC) of 0.8. 6 The LNS scores were derived from a retrospective cohort of 1817 neonates.…”

“…6 In our original description, the LNS score yielded a good diagnostic performance with an area under the receiver-operating characteristics curve (AUC) of 0.8. 6 The LNS scores were derived from a retrospective cohort of 1817 neonates. We used coefficients derived from Cox proportional hazard models to compose the scoring rule.…”

“…We then validated the clinical prediction score in 73 neonates in the same hospital who were evaluated for sepsis. 6 The scaling of the prediction score is shown in Table 1.…”