Objective Due to potential short-term and long-term complications, adequate lifelong follow-up is crucial for patients after bariatric surgery. However, compliance with postoperative follow-up is poor despite clear national and international guidelines. This feasibility trial aimed to evaluate the usability of a smartphone application-based follow-up program in patients after bariatric surgery. Methods Patients were included after having undergone a primary bariatric surgery. Instead of attending meetings in our outpatient clinic, they were followed up using a smartphone application. After 6 months, the System Usability Scale (SUS) was used to measure participant perception. Additional interviews were performed to gain more insight into the usability of the app. Results Between August 2020 and February 2021, 52 patients met the inclusion criteria and agreed to participate in the study, of whom 5 (9.6%) dropped out of the study. At the time of analysis, 31 patients have been followed up for 6 months, among whom 26 patients completed the SUS questionnaire. The mean overall score of SUS is 82.1 ± 19.8. In the qualitative analysis, participants were generally positive about the follow-up care and found it easy to use, despite some minor technical problems. Conclusion Our smartphone app-based follow-up program was proven to be effective in the aftercare succeeding bariatric surgery. Our data indicates that the satisfaction, efficiency, learnability, and ease of use of the smartphone application were coherent in the acceptance and use of mobile technology by patients.

Purpose Medical follow-up after bariatric surgery is recommended. However, the compliance was poor. This study aimed to evaluate the feasibility of a smartphone-based fully remote follow-up (FU) program for patients after bariatric surgery. Methods In the interventional group, patients were followed up using a smartphone application (app), through which questionnaires were sent regularly. Participants in the control group underwent standard FU at the outpatient clinic every three months. After 12 months, all the participants were evaluated at an outpatient clinic. Results Between August 2020 and March 2021, 44 and 43 patients in the interventional and control groups, respectively, were included in the analysis after three patients were lost to FU, and three withdrew their informed consent because they wished for more personal contact with medical caregivers. After 12 months, total weight loss (TWL), %TWL, and percentage of excess weight loss (%EWL) did not differ between groups. There were no significant differences in the complication rates, including surgical complications, malnutrition, and micronutrition deficiency. The parameters of bioelectrical impedance analysis and quality of life did not differ between the groups. Vitamins and minerals in serum were similar in both groups except for calcium, which was significantly higher in the interventional group (2.52 mmol/L vs. 2.35 mmol/L, p = 0.038). Conclusion Fully remote FU with a smartphone application is at least as effective as traditional in-person FU in an outpatient clinic after bariatric surgery. Through remote FU, patients can save time and medical professionals may have more resources for patients with more severe problems. Graphical Abstract