Metformin After Bariatric Surgery: Necessary or Not?

TOPLINE:
Patients who achieved an A1c level < 6.5% after metabolic bariatric surgery (MBS) maintained this target in the short and long terms, regardless of whether they continued or discontinued metformin after the procedure.
METHODOLOGY:
MBS is effective in individuals with type 2 diabetes (T2D) and obesity, but the recommendations for managing patients who achieve diabetes remission after bariatric surgery are not clear.
Researchers conducted a retrospective cohort study using electronic health records from Clalit Health Services in Israel to assess the association between metformin continuation after MBS and the short- and long-term relapse of diabetes (2 and 5 years after surgery, respectively).
They included 366 patients (aged ≥ 24 years; body mass index [BMI], ≥ 30) with obesity and T2D who received metformin and achieved A1c levels < 6.5% for up to 6 months after MBS.
Patients who continued metformin (n = 122; ≥ 3 filled prescriptions; mean follow-up, 5.3 years) were matched and compared with those who discontinued it (n = 244; 0 prescriptions; mean follow-up, 5.8 years) after MBS.
The primary outcome was the long-term relapse of diabetes, defined by an A1c level ≥ 6.5% during the follow-up period, and the secondary outcomes were short- and long-term A1c levels, changes in BMI, and all-cause mortality.
TAKEAWAY:
After adjusting for patient variables, no significant association was found between metformin continuation after MBS and risk for relapse of diabetes (adjusted hazard ratio, 1.65).
Patients in both groups maintained mean A1c levels < 6.5% during the short- and long-term follow-up periods, showing that discontinuing metformin did not impede glycemic control.
No significant differences were noted between patients who continued or discontinued metformin in terms of weight loss.
The mortality rate was low in both the groups, with no substantial difference noted between the groups that continued metformin (4.1%) or discontinued metformin (2.5%).
IN PRACTICE:
“The lack of a significant association of metformin continuation with A1c level observed in the current study supports the notion that metformin may not have an additional benefit after MBS,” the authors wrote.
SOURCE:
This study was led by Dror Dicker, MD, Internal Medicine Department D and Obesity Clinic, Hasharon Hospital, Rabin Medical Center, Petah Tikva, Israel, and published online in Diabetes, Obesity and Metabolism.
LIMITATIONS: 
The observational nature of the study and the lack of randomization may have introduced residual confounding. The small number of patients remaining in the final study population limited the generalizability of the findings. The follow-up period of approximately 5 years may not have been sufficient to observe the long-term effects of metformin continuation.
DISCLOSURES:
The study received funding from Ariel University. Two authors disclosed receiving grants, personal fees, or nonfinancial support from various sources unrelated to this study.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
 
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