INTRODUCTION: Two phase 3 randomized controlled studies (ADJUNCT ONE (Clinicaltrials.gov: NCT01836523), ADJUNCT TWO (Clinicaltrials.gov: NCT02098395)) evaluated liraglutide (1.8, 1.2 or 0.6 mg) vs placebo in participants with type 1 diabetes (T1D) as an adjunct to insulin therapy. This paper aims to improve our understanding of the potential mechanisms leading to premature discontinuation of this treatment regimen. METHODS: Post hoc comparisons were conducted on baseline characteristics and adverse event (AE) rates of participants completing and not completing the ADJUNCT studies due to AEs/lack of tolerance using summary tables and variance analysis. RESULTS: Non-completers (liraglutide and placebo combined) had lower baseline body mass index (BMI) (ADJUNCT ONE: 27.8 kg/m CONCLUSION: Individuals with longer-standing T1D and low levels of C-peptide at baseline were more likely to discontinue adjunctive liraglutide treatment due to AEs/lack of tolerance than individuals with residual insulin production. Lower BMI predicted a greater likelihood of non-completion for the included participants, regardless of treatment. These new findings may be relevant for clinical practice.