Impact of behavioral phenotypes on response to a digital intervention to improve physical activity among postpartum individuals with hypertensive disorders of pregnancy.

Importance: Hypertensive disorders of pregnancy (HDP) increase cardiovascular disease risk. Postpartum interventions can motivate lifestyle changes but are not universally effective.

Objective: Our objective was to determine how behavioral phenotypes are associated with response to a digital health intervention designed to increase physical activity among 122 postpartum individuals with HDP.

Design and methods: We conducted a secondary analysis of the STEP UP Mom trial, comparing a wearable step tracker with team-based gamification to a wearable step tracker alone over 12 weeks. Baseline behavioral characteristics were obtained using validated surveys. We applied the k-means clustering method to identify clusters.

Main outcome and measure: Linear mixed-effects models were used to estimate mean step count difference between arms from baseline across follow-up within each cluster.

Results: We identified two distinct, non-overlapping clusters. Cluster 1 had higher baseline steps and greater psychosocial distress, without significant difference in change in step count in the intervention arm compared to the control arm. Cluster 2 had lower baseline steps and less psychosocial distress and walked 1,335 significantly more steps per day in the intervention arm compared to the control arm. Sustained engagement with the study intervention did not differ between clusters.

Conclusions and relevance: Behavioral phenotypes may help identify postpartum individuals who may benefit from tailored interventions in future studies to improve lifestyle changes.