Qualitative interviews
A total of 135 patients in the intervention arms (opt-out and incentive arms only) were randomly selected to be contacted for a postintervention interview (stratified by batch). Of these, 18 interviews (13.3%) were completed, 37 declined (27.4%), 69 were unreachable (51.1%), and 11 had other issues (8.1%). Of the 5 that specifically remembered the letter, 4 found it to be useful. Almost half of the patients (n=7) preferred to schedule the ultrasound by phone, while one third (n=6) preferred to schedule during the office visit. Five patients found the patient portal useful for engagement, and 4 patients had issues with receiving mail from the postal service due to reliability. Five patients had to put off liver surveillance due to the COVID-19 pandemic, 3 patients appreciated the gift card, and 3 had issues with transportation to receive the ultrasound.