Abstract
BACKGROUND: Maternal sensitivity is a crucial factor in fostering infants' resilience and healthy development. Parent-Infant Psychotherapy (PIP) interventions focus on the improvement of maternal or paternal sensitivity, among other outcomes. Little is known about their cost-effectiveness. This study aimed to evaluate the cost-effectiveness of a short-term PIP compared to care as usual (CAU) in Germany. METHODS: Cost-effectiveness analyses were conducted in two randomized controlled trials (RCTs) of the SKKIPPI project, which investigated the efficacy of a six-week PIP program compared to CAU. PIP aimed to support the establishment and maintenance of healthy parent-infant relationships. The first RCT (RCT-M) focused on mothers with postpartum mental disorders and their infants, while the second (RCT-I) examined children aged 0-36 months with regulatory problems and their mothers. Maternal sensitivity was assessed using the sensitivity subscale of the Emotional Availability Scale (EAS) at baseline, six weeks (primary endpoint), and twelve months, with scores ranging from 1 to 7 (Likert Scale) and higher values showing better sensitivity. Group differences were evaluated using ANCOVAs, adjusted for baseline values and treatment settings (inpatient/outpatient). Health care resource utilization was self-reported via questionnaires at baseline and after twelve months. Costs were estimated using standardized unit costs, and gamma-distributed generalized linear models with log link functions were applied to evaluate cost differences between groups from enrollment to twelve months from a payer's perspective. Incremental Cost-Effectiveness Ratio (ICER) was calculated if applicable. RESULTS: Between 2019 and 2021, 51 participants (25 PIP) of RCT-M, and 70 participants (38 PIP) of RCT-I could be included in our analyses. In RCT-M, adjusted EAS scores were slightly lower in the PIP group after twelve months (Δ -0.22, 95% CI -0.55 to 0.11), with higher adjusted costs in the PIP group (Δ €5,603). In RCT-I, the PIP group showed slightly higher adjusted EAS scores (Δ 0.12, 95% CI -0.13 to 0.36), resulting in an ICER of €29,600 per EAS unit gained. Results remained robust in sensitivity analyses. CONCLUSION: Cost-effectiveness of the evaluated PIP in improving maternal sensitivity was unlikely in both trials. Future research could focus on mothers with more severe maternal sensitivity problems and alternative effectiveness measures. TRIAL REGISTRATION: German Register for Clinical Trials, ID: DRKS00016353 (RCT-M) and ID: DRKS00017008 (RCT-I).