Adoption in Canada of an international risk scoring tool to predict respiratory syncytial virus hospitalization in moderate-to-late preterm infants

Abstract

Objective

The advisory board to the Ontario Ministry of Health considered adopting the new three-variable international risk scoring tool (IRST) to guide prophylaxis against respiratory syncytial virus hospitalization (RSVH) in moderate-to-late preterm infants born 32–35 weeks’ gestational age (wGA). Canada currently uses a nationally validated, seven-variable RST, to predict RSVH in 33–35 wGA infants. We explored the potential implications of switching from the Canadian to the IRST.

Methods

Predictive accuracy (area under the receiver operating characteristic curve [AUROC]) of the two RSTs and correlations (Spearman rank) and number needed to treat (NNT) between cut-off scores for low-, moderate- and high-risk subjects were assessed.

Results

The RSTs contain many of the same risk factors (birth proximity to the RSV season, smoking, siblings, daycare), with the Canadian RST also including sex, small for GA and familial eczema. Predictive accuracy was similar (AUROC, IRST: 0.773 [sensitivity: 68.9%; specificity: 73.0%] vs Canadian: 0.762 [68.2%; 71.9%]). Significant correlations between cut-off scores (p < .001) and risk categories (p < .001) were apparent, although the correlation coefficients were weak for both (scores: 0.217; categories: 0.055). While the proportion of high-risk infants was similar (IRST: 0.7% vs Canadian: 0.6%), the NNT was lower for the Canadian RST (7.5 vs 14.3), and more infants were assigned moderate risk by the IRST (19.9% vs 9.8%).

Conclusions

The IRST can be considered simpler (fewer risk factors) than the Canadian RST and its adoption may reduce the number of RSVHs among moderate-to-late preterm infants; however, the cost-effective implications for RSV prophylaxis warrant further investigation.

Keywords:

• Respiratory syncytial virus
• lower respiratory tract infection
• prematurity
• risk assessment
• risk factors
• prophylaxis

Transparency

Declaration of funding

This paper was not funded.

Declaration of financial/other relationships

X.C.E. and B.P. have disclosed that they have received research funding and/or compensation as advisor/lecturer from AbbVie. B.S.R.G. and J.R.F. have disclosed that, working previously for Strategen, they have received payment from AbbVie for work on various projects. CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

All authors were involved in the research design, analysis and interpretation of the data; drafting, revising and approving the paper; and agree to be accountable for all aspects of the work.

Acknowledgements

No assistance in the preparation of this article is declared. The authors would like to thank all those involved in the development of the Canadian RST and IRST, in particular Dr Margaret Sheridan-Pereira, lead investigator on the PREMI study, the data of which are used in all presented analyses. This work was previously presented as posters at the 9th ICCN International Conference on Clinical Neonatology (3–5 September 2020) and European Society for Paediatric Infectious Diseases (ESPID) Annual Meeting (26–29 October 2020).

Data availability statement

Any queries about the data used in this paper can be made to the corresponding author.