Preoperative Glycemic Control May Predict Diabetes Remission After Metabolic Surgery: Study
Brazil: Researchers have found in a new study that preoperative capillary blood glucose levels show good specificity in predicting remission of type 2 diabetes mellitus after surgery. These findings highlight the importance of early glycemic control as a useful clinical marker for anticipating successful surgical outcomes in patients with type 2 diabetes.
Obesity and type 2 diabetes mellitus (T2DM) continue to pose a major global health challenge, with rising prevalence and long-term cardiovascular and metabolic complications. Bariatric surgery, particularly Roux-en-Y gastric bypass (RYGB), has emerged as an effective intervention not only for sustained weight loss but also for long-term remission of T2DM. However, identifying simple and reliable predictors of diabetes remission before surgery remains a key clinical need.
In this context, a study published in Arquivos Brasileiros de Cirurgia Digestiva by Mariana Fior Frias Thomaz from the Universidade de São Paulo, Faculty of Medicine, and colleagues explored whether early glycemic response to a very low-calorie diet (VLCD) could predict long-term diabetes remission following bariatric surgery. The researchers focused on capillary blood glucose measurements as a low-cost and easily accessible clinical tool.
The retrospective cohort study included 198 patients with obesity and T2DM who were scheduled to undergo RYGB. All participants followed a strict preoperative VLCD of 600 kcal per day for at least five days. During this period, capillary blood glucose levels were monitored four times daily. Diabetes remission was defined as achieving an HbA1c level below 6% for at least one year without the need for glucose-lowering medications.
Key Findings:
- Complete remission of type 2 diabetes mellitus was observed in 66.7% of patients following bariatric surgery.
- Early glycemic response during the very low-calorie diet was closely linked to long-term outcomes.
- Patients who achieved capillary blood glucose levels of ≤143 mg/dL by the second day of the diet had a more than 70% chance of diabetes remission at two years.
- Early improvement in blood glucose emerged as a strong predictor of sustained metabolic remission after surgery.
The authors note that a rapid drop in blood glucose during short-term caloric restriction may indicate preserved beta-cell function and better insulin sensitivity—both crucial for diabetes remission after bariatric surgery. Compared with complex or costly predictive methods, simple capillary glucose monitoring during a brief dietary intervention appears to be a practical and easily scalable tool for routine clinical practice.
The findings also highlight the importance of preoperative metabolic optimization in bariatric care. Early dietary responses may help clinicians identify patients more likely to achieve long-term diabetes remission, supporting individualized counseling, realistic expectation setting, and tailored postoperative follow-up. Although prospective studies are needed for further validation, the results highlight early glycemic response to a very low-calorie diet as a meaningful and clinically useful predictor of sustained metabolic benefit after surgery.
Reference:
Bortolan MFFT, De Cleva R, Ferreira L, Pajecki D, Santo MA. Preoperative glycemic response to a very lowcalorie diet predicts long-term type 2 diabetes remission after bariatric surgery. ABCD Arq Bras Cir Dig. 2025;38:e1919. https://doi.org/10.1590/0102-67202025000050e1919.
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