Identifying treatment moderators of a trauma-informed parenting intervention with children in foster care: Using model-based recursive partitioning

Delivery and Impact of Foster Parent Training: Similarities and Differences for Relative and Non-Relative Foster Parents

Literature on the delivery and impact of foster parent training, such as the Nurturing Parenting Program (NPP), is sparse, particularly for relative foster parents. This study investigates (a) how NPP referral, initiation, and completion rates vary between relative and non-relative foster parents, (b) reasons for not initiating NPP, and (c) changes in parenting attitudes and behaviors for relative and non-relative foster parents after participating in NPP. The study analyzed data from the Illinois Birth to Three (IB3) study for 722 relative and 397 non-relative foster parents of children ages three and younger. Relative and non-relative foster parents had similar NPP referral and initiation rates, but relatives had significantly lower completion rates. Content analysis of case notes for 498 cases showed that relative foster parents more frequently noted barriers (e.g., childcare, transportation) to NPP initiation. Among NPP completers, both groups reported similar levels of improvements in parenting attitudes and behaviors at the end of NPP, but a pattern of lower scores was observed for relative foster parents. The findings suggest a need for more support for foster parents, particularly relative foster parents.

Exploring differential response to an emergency department-based care transition intervention

OBJECTIVE

To identify multivariable subgroups of patients with differential responses to a nurse-delivered care transition intervention after an emergency department (ED) visit in a randomized controlled trial (RCT) using an emerging data-driven method.

DESIGN

Secondary analysis of RCT.

PARTICIPANTS

512 individuals enrolled in an RCT of a nurse-delivered care transition intervention after an ED visit. All 512 participants were included in a pre-specified subgroup analysis, and 451 of these had sufficient complete case data to be included in a model-based recursive (MoB) partitioning analysis.

METHODS

The primary outcome was having at least one ED visit in 30 days after the index ED visit. Two analytical methods explored heterogeneity of treatment effects: data driven model-based recursive partitioning (MoB) using 37 candidate baseline variables, and a contextual point of comparison with prespecified subgroups defined by ED super-user status (≥ 3 ED visits in previous 6 months or not), sex (male/female), and age, individually examined via treatment arm by subgroup interaction terms in logistic regression models. Internal validation of the MoB analysis via bootstrap resampling with an optimism corrected c-statistic was conducted to provide a bias-corrected estimate.

RESULTS

MoB detected treatment effect heterogeneity in a single subgroup, marital status. Unmarried patients randomized to the intervention had a repeat ED use rate of 22% compared to 34% in the usual care group; married patients randomized to the intervention had a 27% ED return rate compared to 12% in the usual care group. Internal validation demonstrated an optimism corrected c-statistic of 0.54. No treatment-by-covariate subgroup interactions were identified among the 3 prespecified subgroups.

CONCLUSION

Although exploratory, the results of the MoB analysis suggest that patient factors related to social relationships such as marital status may be important contributors to differential response to a care transition intervention after an ED visit. These were characteristics that the investigators had not anticipated or planned to examine in the individual prespecified subgroup analysis. Data-driven methods can yield unexpected findings and contribute to a more complete understanding of differential treatment effects in subgroup analysis, which can inform further work on development of effective care transition interventions in the ED setting.