Presentation Abstract 293: Postoperative Insulin Requirements in Bariatric Surgery. Danielle Diemer, Melissa Matthews, Karen Terry, Ellen Romich, Heather Saran, Maria Lansang. Presentation from the 25th Annual Scientific and Clinical Congress of the American Association of Clinical Endocrinologists; May 25-29, 2016, Orlando, Florida.
A five-year retrospective study that investigated the insulin requirements of type 2 diabetes (T2D) patients immediately following bariatric surgery demonstrated that Roux-en-Y gastric bypass surgery greatly improved glycemic control in persons with T2D, indicating an 86% reduction in the total daily insulin dose on the second post-operative day.
The study investigators from the Cleveland Clinic's STAMPEDE (Surgical Therapy and Medications Potentially Eradicate Diabetes Efficiently) trial presented their data at the AACE 25th Annual Scientific and Clinical Congress. The study compared baseline and postsurgical insulin dosage requirements and determined perioperative glycemic measures in T2D patients who received bariatric surgery in their clinic between 2010 and 2014.
The retrospective chart review included 114 bariatric patients who were 55% female and 75% Caucasian, with a mean age of 52.8 years. Their mean BMI was 46.2 kg/m2 and mean hemoglobin A1c was 8.3%. Seventy-nine percent of the patients had hypertension, 82% had lipid disorders, and 66% were on insulin plus noninsulin medications, with the remainder (34%) on insulin only.
The study compared BG levels and insulin doses of patients prior to admission (Baseline), on the day of surgery (DOS), and postoperative days 1 and 2 (POD1, POD2), using a paired t-test. Subgroup analyses were performed on patients who demonstrated blood glucose (BG) 100 mg/dL-140 mg/dL more than 50% of the time on POD2, while t-test comparisons were done in patients with poorer BG control.
The study data was as follows: mean BG levels were 185 ± 43 mg/dL on DOS, 171 ± 41 mg/dL on POD1 (P < .0001 vs DOS), and 160 ± 36 mg/dL on POD2 (P < .0001 vs DOS).
The mean daily insulin dose was 85.8 ± 62.9 units at Baseline, 11.5 ± 13.2 units on DOS, 16.8 ± 21.2 units on POD1, and 11.5 ± 15.3 units on POD2, with P < .0001 for all time points vs Baseline.
Among the subgroup of subjects with good control, the A1c was 7.9% ± 1.6. The mean daily insulin dose in this subgroup was 75.6 ± 55.7 units at Baseline, 7.7 ± 7.6 units on DOS, 8.7 ± 11.6 units on POD1, and 4.0 ± 6.2 units on POD2, all with P < .0001 vs Baseline.
On POD2, 95% of patients were on insulin only, which was consistent with recommendations for inpatient T2D treatment, while the rest of the patients were on insulin plus noninsulin medications. Glycemic control on POD1 and POD2 was fair, falling in the upper end of the ADA guidelines of 100 mg/dL-180 mg/dL in hospitalized patients.
Mean BG levels were 160 mg/dL-170 mg/dl on 0.09 units/kg -0.13 units/kg of insulin, corresponding to an 86% reduction, on POD1 and POD2, when patients received a clear liquid diet every hour. This assessment could be useful in developing algorithms for insulin titration after bariatric surgery, according to the investigators.
The group as a whole had an 86% reduction in the total daily dose of insulin by POD2. This reduction was 95% in the subgroup with good glycemic control, despite lower BGs. While patients with type 2 diabetes may be expected to require as much as 50% less insulin while receiving an NPO or clear liquid diet, the 86% reduction in total daily insulin doses suggests the reduced insulin requirements are also due to immediate hormonal changes due to bariatric surgery.