Type 2 Diabetes and HbA1c Predict All-Cause Post-Metabolic and Bariatric Surgery Hospital Readmission
Elisa Morales-Marroquin, Luyu Xie, Luigi Meneghini, Nestor de la Cruz-Muñoz, Jaime P. Almandoz, M. Sunil Mathew, Benjamin E. Schneider, Sarah E. Messiah
- The overall 30-day readmission rate after bariatric surgery was 4.2%.
- Patients with uncontrolled type 2 diabetes (HbA1c above 7.5%) were more likely to be readmitted.
- After adjustment, a diabetes diagnosis alone was not associated with more readmissions; poor control was the key factor.
- Uncontrolled diabetes, diabetes and prediabetes were each associated with less weight loss in the first 30 days.
- Improving blood sugar control before surgery may reduce readmissions.
Using the 2015–2018 national MBSAQIP registry of 744,776 bariatric patients, this study examined whether type 2 diabetes and preoperative HbA1c predict hospital readmission within 30 days of surgery. The overall readmission rate was 4.2%. Patients with uncontrolled diabetes (HbA1c above 7.5%) were more likely to be readmitted, while a diabetes diagnosis alone was not associated with readmission after adjustment. Uncontrolled diabetes, diabetes and prediabetes were all associated with less weight loss in the first 30 days, highlighting the value of optimizing blood sugar before surgery.
Why This Study Was Needed
Type 2 diabetes is one of the strongest reasons to have bariatric surgery, but it may also raise surgical risk. Hospital readmission is a key measure of safety and quality, and it was not clear whether diabetes itself, or how well it is controlled, drives readmissions.
How the Study Was Done
The team analyzed 744,776 patients in the national MBSAQIP registry from 2015 to 2018, of whom 30,972 were readmitted within 30 days. They compared readmission and early weight loss by diabetes status and HbA1c, a measure of average blood sugar over two to three months.
What the Study Found
- The overall 30-day readmission rate was 4.2%.
- Readmission was about 10% higher in patients with uncontrolled diabetes (HbA1c above 7.5%).
- After adjustment, having diabetes by itself was not associated with more readmissions; poor control was what mattered.
- Uncontrolled diabetes, diabetes and prediabetes were all associated with less weight loss in the first 30 days.
What This Means for Patients
If you have diabetes, surgery is often the best treatment you can choose, and many patients go into diabetes remission after surgery. Getting your blood sugar under better control in the weeks before surgery, with medication adjustments or a medical weight loss program, can make your recovery smoother. See pre-op readiness and know the discharge instructions and warning signs.
Clinical Pearls
- HbA1c above 7.5% identifies patients at higher readmission risk.
- Glycemic control, not the diabetes diagnosis itself, drives readmission.
- Preoperative glucose optimization is a practical, modifiable target.
Strengths and Limitations
The study uses a large national sample with standardized outcome reporting. It covers only 30 days, and HbA1c values were not available for every patient.
Expert Commentary
Diabetes should never keep a patient from surgery, because surgery is one of the most effective diabetes treatments we have. But this study showed that walking into the operating room with very high blood sugar adds risk. Optimizing it beforehand is simple and worth it.
— Dr. Nestor de la Cruz-Muñoz
Related Research
Morales-Marroquin E, Xie L, Meneghini L, de la Cruz-Muñoz N, Almandoz JP, Mathew MS, Schneider BE, Messiah SE. Type 2 Diabetes and HbA1c Predict All-Cause Post-Metabolic and Bariatric Surgery Hospital Readmission. Obesity (Silver Spring). 2021;29(1):71-78. doi:10.1002/oby.23044.
