To attend, or not to attend: Examining caregiver intentions and study compliance in a pediatric, randomized controlled trial

Background/aims: The Intent to Attend is a brief questionnaire recommended by the National Research Council to address dropout concerns and improve prediction of missing data in clinical trials, although implementation has been very limited. As a formative study in pediatric research, the relationship between caregiver intentions and study compliance was investigated in a 180-day trial of dietary supplementation of preterm toddlers. Treatment effect estimation in the context of missing data was also explored.

Methods: Study compliance (i.e. study completion, supplement adherence, and diary completion) was tracked over three study visits. Baseline questionnaires asked caregivers about intentions concerning study completion via the Intent to Attend, screened for mental health symptoms (depression, trait anxiety), and captured family demographics. Simple and multiple logistic regression models were built to examine associations between caregiver intent and compliance outcomes. The Intent to Attend was also employed as an auxiliary variable to account for missing data within mixed models estimating the treatment effect on the primary outcomes.

Results: Of the 316 caregiver-child dyads included, 95% of caregivers with low intentions had a child complete the study, but only 87% of caregivers with high intentions had a child complete the study. Low intentions to complete the study were associated with a more than 60% lower odds of study non-completion, but the confidence interval included the null (odds ratio: 0.36; 95% confidence interval: 0.11, 1.20). No effect measure modification by caregiver mental health, child sex, or annual income was detected. Income was the only significant predictor of study non-completion; the lowest income group was almost four times more likely to be study non-completers compared with the highest income group, even after adjustment for child sex and caregiver mental health (adjusted odds ratio = 3.59, 95% confidence interval: 1.38, 9.31). When using Intent to Attend as an auxiliary variable, similar results were obtained when compared with the original treatment effect estimates on the primary outcomes.

Conclusion: Contrary to prior adult studies, there is no clear relationship between caregiver intentions and study compliance. Findings elucidate the complexities of caregiver-child interactions during pediatric trial participation.