Equity effects of parenting interventions for child conduct problems: a pan-European individual participant data meta-analysis

Abstract

Background: Childhood conduct problems are a costly public health problem, five times commoner in socially disadvantaged groups. Untreated, they have a poor prognosis, with increasing gaps between socio-economic groups, and high rates of subsequent criminality. The Incredible Years (IY) is a high-quality parenting programme as recommended by NICE for reducing conduct problems, and is widely disseminated in Europe. Many trials show IY to be effective, but the potential effects on social inequality of parenting interventions are unknown. This matters since some behavioural interventions (e.g. smoking cessation programmes), while beneficial overall, can widen inequality gaps. Since single trials and aggregate-level meta-analysis are ill-equipped for examining differential intervention (moderator) effects, we pooled individual-level trial data. Method: Individual participant data (IPD) meta-analysis of a near-complete set of randomised trials of European IY parenting programmes (k=13; N=1696; for 1/15 trials, data unavailable). Children were aged 2-10 years (M 5.1; 30% minority; 58% low-income). Primary outcome was child conduct problems, measured by Eyberg Child Behavior Inventory (ECBI-I). Moderators were analysed using multilevel modelling with multiple imputation. Findings: IY led to an overall reduction in child conduct problems (estimated 13.5 points on ECBI-I, 95% CI 10.9 to 16.1). There was no evidence for differential effects in families with different levels of social disadvantage (poverty, lone or teen parenthood, joblessness; low education), or from ethnic minorities. Interpretation: This world-first IPD meta-analysis of parenting trials, found IY was equally likely to be effective with disadvantaged as non-disadvantaged children, suggesting the programme is unlikely to widen socioeconomic inequalities in conduct problems. Furthermore, the programme may be an important tool for reducing social disparities and improving the poor long-term outcomes in disadvantaged families, since follow-up studies indicate that benefits persist. Meantime, clinicians and commissioners can be reassured the programme is equally effective for families from different backgrounds