The estimated effect of reducing the maternal smoking rate on neonatal intensive care unit costs in Victorian public hospitals

Keywords: economic, hospital, pregnancy, quit, smoking cessation.

There is currently a national initiative to embed smoking cessation in maternity settings in Victoria, New South Wales and Queensland as part of a national stillbirth prevention package (see https://www.stillbirthcre.org.au/safer-baby-bundle/, accessed 25 September 2020). Women who smoke at any time during pregnancy are at higher risk of preterm delivery (adjusted odds ratio (OR) 1.53, 95% confidence interval (CI) 1.05–2.21), which is associated with poorer pregnancy and birth outcomes including miscarriage, stillbirth and low birthweight, more neonatal intensive care unit (NICU) admissions and readmissions, and longer hospital stays.¹ Although the short-term health and economic benefits of reducing the number of babies of low birthweight due to smoking cessation have been estimated for the US,² to the best of our knowledge there are no similar data published in the Australian setting. This analysis estimates the expected number of Victorian public hospital NICU cot-days that could be saved annually if the maternal smoking rate was reduced by 2%.

The estimates were informed by Victorian prevalence and smoking rate data,³ public hospital statistics from the Victorian Admitted Episodes Dataset (VAED) provided by the Victorian Department of Health and Human Services,⁴ and Victorian tertiary health service 2018/19 clinical costing data.⁵ Data on the total number of preterm babies (28–37 weeks) born to women who smoked during pregnancy (WSdP) and women who did not smoke during pregnancy (WNSdP) and the number and length of NICU stays were used for the estimates (Fig. 1).

Fig. 1.  Proportion of preterm babies admitted to Victorian public hospital neonatal intensive care units (NICUs) in smoking and non-smoking women and length of stay (2016–17). Source: Victorian Admitted Episodes Dataset 2016–17.⁴

Table 1 describes the calculations. In 2016–17, 57 522 women birthed 60 258 babies in Victorian public hospitals. Compared with WNSdP, there was a higher proportion of babies born to WSdP who were preterm (7.8% v. 7.2%), and either admitted to NICU during the birthing episode (21.6% vs 19.0%) or admitted to NICU in their first year of life (but not admitted to NICU during the birthing episode) (35.3% vs 26.9%). On average, preterm babies of WSdP spent more hours in NICU at birth (258 vs 188 h) and throughout the first year of life (53 vs 37 h).

Table 1.  Estimates of the annual expected number of public hospital neonatal intensive care unit (NICU) cot-days saved as a result of reducing the risk of preterm births (28–37 weeks) in smokers by reducing the Victorian maternal smoking rate by 2%
CCOPMM, Consultative Council on Obstetric and Paediatric Mortality and Morbidity³; VAED, Victorian Admitted Episodes Dataset (2016–17)⁴

All else being equal, an estimated 106 public hospital NICU cot-days could be saved over 12 months if the Victorian maternal smoking rate (the rate of smoking during early pregnancy) was reduced from 8.4% to 6.4%, with an estimated annual expected cost saving of A$276 000. Results should be interpreted cautiously as data on preterm births are extracted from the VAED and are subject to confounding. Calculations do not include babies born before 28 weeks, any value to improved postnatal health outcomes, or gains in quitting expected if brief advice resulted in the use of multi-session behavioural intervention, such as that provided by the Quitline.^6,7 Bell et al.⁸ demonstrated the odds of quitting smoking by delivery is almost doubled (adjusted OR 1.81, 95% CI 1.54–2.12) when a comprehensive smoking cessation approach is implemented.

The findings indicate embedding brief advice and opt-out referral to Quitline as part of routine maternal care could significantly improve pregnancy and birth outcomes and alleviate scarce public hospital resources.

Dr White manages the Victorian Quitline, which is funded by the State Government of Victoria to provide the population-level behavioural intervention service for smoking cessation. Dr McCaffrey and Mr Dowling declare no competing interests.