Follow up and assessment of outcomes
All participants underwent two assessments: baseline (pre-randomization; 6 weeks to 6 months postpartum) and at study completion (8-12 months postpartum) after completing at least 6 months in the study. Enrolled participants were emailed a link to a questionnaire, which was completed before or at the time of the first two study visits. Before March 2020, all participants underwent a study visit either in the Magee-Womens Clinical and Translational Research Center (CTRC) or via home research study visits, per participant preference. After March 2020 (due to COVID pandemic restrictions), study visits were conducted remotely. At the time of each assessment, participants completed online questionnaires and measured blood pressure at rest, while sitting for at least 5 minutes. Blood pressure measures were either collected by study staff (pre-pandemic) or observed by study staff virtually using a secured Zoom room and were repeated three times. Blood pressures were measured using either an iHealth, Wireless Blood Pressure Monitor BP5 or an A&D UA-651 (A&D Medical; San Jose, California) automatic upper arm blood pressure monitor, both validated by Dabl Educational Trust and the British Society for Hypertension for use in postpartum individuals. The mean of the three measures was used in analysis. Mean arterial pressure was calculated with the formula [systolic BP+(2*diastolic BP)/3]. Weight measures were collected either by study staff during an in-person visit, pre-pandemic, or were directly observed during a remote study visit using a study-provided iHealth or Etekcity Digital Body Weight scale. Individuals were weighed in light clothing without shoes at the time of the study visit for both in-person and remote study visits. Participants in all three arms received monthly emails thanking them for their ongoing participation.
The primary objective of this pilot study was to evaluate the feasibility of a randomized trial of home blood pressure monitoring vs home blood pressure monitoring plus a lifestyle intervention vs control in the first year postpartum. Feasibility of recruitment and retention (proportion and 95% CI) was assessed to study completion. Our predefined measures for feasibility success included randomization of 8-10 participants per month and retention of ≥80% of participants to one-year postpartum, with a target to complete all recruitment at the primary site during an 18-month period and recruitment at both sites over a 24-month period. Our primary efficacy outcome was participant weight at the second study visit, which was chosen as a patient-centered outcome for postpartum individuals. Secondary outcomes included: 1) blood pressure and change in blood pressure parameters across the study; 2) participant BMI and weight change across the study, 3) adherence to intervention, 4) self-efficacy 5) prevalence of stage 1 and 2 HTN, 6) use of anti-hypertensive medications at study completion and 7) prevalence of lifestyle behaviors. Stage 1 and stage 2 hypertension were defined using the 2017 American College of Cardiology / American Heart Association guidelines - stage 1 hypertension: systolic BP 130-139 mmHg or diastolic BP 80-89 mmHg and stage 2 hypertension: systolic BP ≥140 mmHg, diastolic BP ≥90 mmHg or requiring anti-hypertensive medications.(22)
Self-efficacy towards achieving a healthy diet and level of physical activity was assessed using an adapted version of the validated Sallis Eating Habits Confidence Survey and Exercise Confidence Survey scales.(23) We used the Pregnancy Physical Activity Questionnaire to assess physical activity (type, duration, and frequency) and inactivity (sedentary behavior), which is a validated questionnaire for women that includes activities related to caring for young children. Time spent in each activity weekly is multiplied by its intensity to yield the average weekly energy expenditure.(24) Sodium intake was quantified using an adapted version of the validated Sodium Screener developed by Block (©NutritionQuest 2011) to assess sodium intake as a continuous variable. The Sodium Screener includes foods contributing to 80% of sodium intake in which there are five frequency response categories—from rarely or never (assigned a value of 0) to every day (assigned a value of 4). The cumulative score ranges from 0 to 67, with higher scores signifying higher sodium intakes. For women, sodium intake less than 2300 mg per day corresponds to scores between 18-24.(25)
A core outcome set (COS) does not exist for this research subject area, thus a COS was not used when designing the trial.