Cost-effectiveness analysis of induction of labour at 41 weeks and expectant management until 42 weeks in low risk women (INDEX trial)

OBJECTIVE: To assess the cost-effectiveness of elective induction of labour (IOL) at 41 weeks and expectant management (EM) until 42 weeks. DESIGN: Cost-effectiveness analysis from a healthcare perspective alongside a randomised controlled trial (INDEX). SETTING: 123 primary care midwifery practices and 45 obstetric departments of hospitals in the Netherlands. POPULATION: We studied 1801 low-risk women with late-term pregnancy, randomised to IOL at 41 weeks (N = 900) or EM until 42 weeks (N = 901). METHODS: The incremental cost-effectiveness ratio (ICER) was expressed as the ratio of the difference in costs and the difference in main perinatal outcomes. A Cost-Effectiveness Acceptability Curve (CEAC) was constructed to assess whether induction is cost-effective for a range of monetary values as thresholds. We performed subgroup analysis for parity. MAIN OUTCOME MEASURES: Direct medical costs, composite adverse perinatal outcome (CAPO) (perinatal mortality, NICU admission, Apgar 5 min < 7, plexus brachialis injury and/or meconium aspiration syndrome) and composite severe adverse perinatal outcome (SAPO) (including Apgar 5 min < 4 instead of < 7). RESULTS: The average costs were €3858 in the induction group and €3723 in the expectant group (mean difference €135; 95 % CI −235 to 493). The ICERs of IOL compared to EM to prevent one additional CAPO and SAPO was €9436 and €14,994, respectively. The CEAC showed a 80 % chance of IOL being cost-effective with a willingness-to-pay of €22,000 for prevention of one CAPO and €50,000 for one SAPO. Subgroup analysis showed a willingness-to-pay to prevent one CAPO for nulliparous of €47,000 and for multiparous €190,000. To prevent one SAPO the willingness-to-pay is €62,000 for nulliparous and €970,000 for multiparous women. CONCLUSIONS: Induction at 41 weeks has an 80 % chance of being cost-effective at a willingness-to-pay of €22,000 for prevention of one CAPO and €50,000 for prevention of one SAPO. Subgroup analysis suggests that induction could be cost-effective for nulliparous women while it is unlikely cost-effective for multiparous women. Cost-effectiveness in other settings will depend on baseline characteristics of the population and health system organisation and funding.