Pragmatic strategies to improve reach and representativeness in a hybrid type 1 hypertension trial in older adults

Results of clinical trials are often not generalizable as the trial cohort often does not represent older and real-world populations. In a hybrid type 1 effectiveness-implementation study of remote monitoring and management of hypertension, we used pragmatic enrollment and intervention strategies to improve reach and enroll a trial cohort similar to the older primary care clinic population with uncontrolled hypertension. We evaluated whether prespecified pragmatic strategies — including broad inclusion criteria, automated identification, an opt-out approach to initial contact, low study burden, phone-based study visits, and stakeholder engagement — were associated with improved source-population reach and reduced enrollment bias. We performed a cross-sectional analysis of enrollment data from a multicenter randomized controlled hybrid type 1 trial enrolling adults 65 years or older with inadequately controlled hypertension from primary care clinics within two large health systems. We compared characteristics of enrolled patients with those of all eligible primary care patients meeting criteria for guideline directed blood pressure lowering. Among 64,671 patients 65 years or older who had primary care visits during the enrollment period, 6,006 were potentially eligible and 1,000 were enrolled and randomized, yielding a source-population reach of 16.7%. Compared with eligible non-enrolled patients, enrolled patients were slightly younger (73 ± 6 vs. 75 ± 7 years) and had a lower prevalence of stroke (5.9% vs. 8.9%). The groups were otherwise similar with respect to sex, Black race, Charlson comorbidity index, diabetes, coronary artery disease, and estimated glomerular filtration rate. Logically integrated, prespecified, pragmatic enrollment strategies supported enrollment of a cohort of older adults with hypertension that was similar to the eligible primary care population across key measured characteristics. These strategies may serve as a framework for trials seeking to improve external validation. This trial is registered in clinicaltrials.org as “Remote Monitoring and Virtual Collaborative Care for Hypertension Control to Prevent Cognitive Decline Phase II (vCCC 2)” NCT05138601 with a registration date of 12-01-2021. NCT5138601.