ST analysis plus CTG compared to CTG alone for intrapartum fetal monitoring (the START randomised controlled trial): A cost minimisation study.

Abstract

Objective: To undertake a cost minimisation study of ST analysis (STan) plus cardiotocograpy (CTG) compared to CTG alone. Design: Cost-minimisation analysis alongside a randomised controlled trial [(1)](#ref-0001). Setting: A tertiary level maternity centre in Adelaide, South Australia. Population: Women in labour ≥36 weeks gestation, with a clinical indication for continuous electronic fetal monitoring. Methods: We utlilised a health service perspective covering randomisation to final maternal and neonatal discharge, including readmissions. Primary analysis was intention to treat, with secondary per protocol analysis. Post hoc analyses were conducted by sub-groups and after exclusion of outliers. Main outcome measure: Average cost per mother/baby dyad. Results: Costs were calculated for 957/968 patients (98.9%) using hospital financial data. There was no statistically significant evidence of difference between the two study arms but lower costs observed in the STan arm. Average cost per mother/baby dyad was AUD12,768 for Stan+CTG, compared with AUD15,027 for CTG alone. Lower costs were mainly due to lower neonatal costs, particularly for critical care. Maternal labour cost was nearly identical in the two arms. The difference was still shown, although with reduced magnitude, when outliers were removed and increased with a per protocol analysis. Conclusion: While not statistically significant, reduced costs were observed in the CTG+STan arm (average reduction per mother / baby dyad = AUD2,259).

Comparison of effect of CTG + STan with CTG alone on emergency Cesarean section rate: STan Australian Randomized controlled Trial (START)

“…With the actual number randomized, the statistical power to detect the original difference of 5% was only approximately 56%. At the time of performing power and sample size calculations for the trial 20 , the rate of EmCS at the trial institution was approximately 18% (WCH Clinical Information Service (CIS) data, 2015); this proportion was revised down to 17% for the power calculation, due to introduction of a rigorous fetal surveillance education program mandated by the health department for all obstetric and midwifery staff involved in intrapartum care. We considered that this program itself would decrease the WCH EmCS rate, regardless of the addition of STan as an adjunct to CTG.…”

“…Therefore, sample size was based on data from our pilot study 20 , FBS reduction rates and the observed rate of EmCS at the WCH. The proportion of EmCS deliveries in the CTG only (control) group was expected to be approximately 17%, and the sample size was intended to provide 80% power (with two-sided α = 0.05) to detect a 5% absolute reduction in the rate of EmCS in the CTG + STan group (i.e.…”