N-of-1 trials to find the highest tolerated beta-blocker dose in heart failure

In this study we seek to understand whether N-of-1 trials using a crossover withdrawal/reversal design with 1-5 three-week periods can be used to identify the highest tolerated beta-blocker dose for patients with Heart Failure with Reduced Ejection Fraction (HFrEF). To achieve this objective we will conduct a 2-arm randomized controlled trial of 50 participants, comparing intervention(N-of-1 trials) to enhanced usual care.

For participants randomized to the intervention, we will use collect data via validated patient-reported outcomes and then display this data on a visualization tool. This tool was iteratively developed for N-of-1 trials with patient input - a comparison of how the patient felt on different doses of the same beta-blocker. If well-tolerated and the participant agrees to continue with dose escalation based on review of their data, the participant will take a higher dose for the next 3-week period; and the study team will again collect data on how they feel during this time. This approach of sharing end-of-period data with participants and subsequently escalating the dose (based on the participant's decision) for another 3-week period will continue until the guideline-directed target dose is reached or until the participant feels that their symptoms are limiting dose escalation. The N-of-1 intervention is purposefully structured to allow the participant to participate in 1-5 three-week periods (and as many dose combinations) as they wish until they are confident that they have reached their highest tolerated dose. This adaptive design for N-of-1 trials is intended to be patient-centered and patient-driven.

We will also conduct brief semi-structured interviews with intervention participants.

Participants randomized to enhanced usual care will not have access to patient-reported outcomes or the data visualization tool. Since attention can affect outcomes, we will "enhance usual care" by conducting phone calls at the same frequency as the intervention group.