Equity impact on cost-effectiveness
We assessed child cognitive development score across socioeconomic groups by trial arms (Child cognitive score by (a) household wealth quintile and (b) mother’s education level. The difference in cognitive development score between the intervention and control arms was statistically significant in children from the poorest quintile but not in those from richest quintile (There was a wide range of 95% CI for out-of-pocket healthcare costs in all subgroups with no significant difference between the trial arms (Cost-effectiveness to improve child cognitive development by household wealth quintile and mother’s education level (base-case)Costs are in US$ 2019.Intervention cost data from the trial’s main cost-effectiveness study (Outcome and cost by household wealth quintile are adjusted for the number of household members, parity, mother’s age, mother’s occupation, father’s age, father’s education, father’s occupation and mother’s education. Outcome and cost by mother’s education are adjusted for the number of household members, parity, mother’s age, mother’s occupation, father’s age, father’s education, father’s occupation and household wealth.The base-case ICER per cognitive development score gained showed that the intervention was more cost-effective in children from two poorest quintiles than richer quintiles (The mean ICER of bootstrap samples ranged from −US$13 (95% CI −62 to 21) in Quintile 2 to US$25 in Quintile 4 (95% CI −2 to 87) based on intervention recurrent cost when adjusting for cluster effects and baseline characteristics (ICERs per child cognitive development score gained by household wealth quintile and mother’s education level (1000 times bootstrapping)Costs are in US$ 2019. ICER = Incremental cost-effectiveness ratios.Outcome and cost by household wealth quintile are adjusted for the number of household members, parity, mother’s age, mother’s occupation, father’s age, father’s education, father’s occupation, and mother’s education. Outcome and cost by mother’s education are adjusted for the number of household members, parity, mother’s age, mother’s occupation, father’s age, father’s education, father’s occupation, and household wealth.The probability that the intervention was cost-saving or cost-effective was estimated based on 1000 bootstrapped estimates. The estimates in the north-east quadrant on the cost-effectiveness plane (Cost-effectiveness plane of 1000 bootstrap iterations by (a) household wealth quintile and (b) mother’s education level based on intervention recurrent cost and out-of-pocket healthcare cost. Costs are in US dollars (USD) 2019.