OBJECTIVES: To conduct a systematic literature review exploring if weight change during treatment of type 2 diabetes (T2D) is associated with medication adherence and/or discontinuation.

METHODS: A literature search of MEDLINE, EMBASE, and recent congress abstracts was conducted to identify studies (January 2005 to September 2020) reporting objective data on weight change and adherence and/or discontinuation in people with T2D (PwD) treated with diabetes medications.

RESULTS: Nine studies were identified from 9188 records. Studies evaluated the association between weight change and adherence (n=6), discontinuation (n=2), and adherence and discontinuation (n=1). Four reported absolute weight change (kg) by adherence: three found the direction of change followed known weight profiles (loss or gain) of the evaluated drug; one demonstrated greater weight loss in adherent versus non-adherent PwD even when data from drugs with different weight profiles were pooled. Two studies reported the proportion of PwD achieving categorical weight loss (≥3%) by adherence: one showed that more adherent versus non-adherent PwD lost ≥3% weight within 3–6 months of glucagon-like peptide-1 agonist initiation; the second demonstrated that ≥3% weight loss occurred more commonly in adherent PwD regardless of weight profile of the evaluated drug. One study reported adherence according to categorical weight change: adherence improved with increasing weight loss regardless of the drug received (loss/gain profile). All three discontinuation studies reported that PwD who lost weight versus gained weight were less likely to discontinue therapy.

CONCLUSIONS: Our findings suggest weight gain is associated with discontinuation, but the relationship between on-treatment adherence and weight change is more complex. Further evidence from longitudinal studies is needed to evaluate causality between weight change on T2D medication and adherence/discontinuation. Supporting better diabetes medication adherence and persistence is key in improving outcomes; therefore, further exploration of weight as an important influencer in this regard is warranted.