Comment on Kim et al. The Effect of a Smartphone-Based, Patient-Centered Diabetes Care System in Patients With Type 2 Diabetes: A Randomized, Controlled Trial for 24 Weeks. Diabetes Care 2019;42:3–9

We read with interest the article by Kim et al. (1), which demonstrated the potential benefits of a smartphone-based, patient-centered diabetes care system (mDiabetes) for improving glycemic control among patients with type 2 diabetes.We commend the substantial achievement of completing this trial but would like to add some comments concerning the interpretation of the results.Intention-to-treat analyses are recommended for avoiding bias when estimating treatment effects, particularly when not all participants complete a trial.Of the 191 patients randomized in this study, only 172 patients were included in the full analysis.Nineteen (10%) patients who were excluded either withdrew, did not complete follow-up, or did not meet the inclusion/exclusion criteria.Patients who withdraw or are not adherent are likely to be systematically different from those who complete a study, thus excluding these randomized patients will have introduced bias.The