Type II diabetes mellitus, a chronic and potentially fatal illness, may be improved with strict diet adherence, weight loss, and drug regimen, but optimal control or resolution of the disease is rarely achieved using these methods. Bariatric surgery has been successful in the treatment of type II diabetes mellitus. Recent studies have shown that bariatric surgery has antidiabetic effects with the normalization of serum glucose levels following bariatric surgery being measured long before any significant weight loss is observed. There is evidence that shows that greater than 80% of patients who undergo RYGB have a complete sustained remission of their type 2 diabetes mellitus [8
]. The patient in our case review had complete resolution of her T2DM within six months of her surgery and neither required oral hypoglycemic nor insulin therapy after postoperative day 10. Her HbA1c values achieved percentages of 6.1 at 6 months and 5.9 at her 2-year followup ().
Patient's HbA1C levels 3 months preoperatively through 24 months postoperatively.
Currently, there are few reports on the laparoscopic surgical treatment of patients with T2DM and a BMI lower than 35. The first report was by DePaula et al. in 2008. In his retrospective cohort study DePaula found that “weight loss was not a reliable predictor of (T2DM) resolution or glucose control” in postgastrectomy patients. He reported 39 patients with a BMI less than 35 who underwent either a laparoscopic ileal interposition procedure associated with a sleeve gastrectomy or a laparoscopic ileal interposition procedure associated with a diverted sleeve gastrectomy. The inclusion criteria for the study specified T2DM patients whose disease had been diagnosed for at least 3 years; documentation of HbA1c exceeding 7.5% for at least 3 months; stable weight, defined as no significant change (>3%) over the 3 months before enrollment; evidence of stable treatment with oral hypoglycemic therapy or insulin for at least 12 months. All patients had a BMI less than 35
. In fact, the mean BMI was 30.1
. Of the 39 patients included in the study, 86.9% achieved adequate glycemic control defined as a HbA1c <7% during a mean follow-up period of 7 months [8
]. One significant finding in this paper was that zero patients required insulin therapy postoperatively. DePaula also reported that the mean percentage of weight loss was 22% and the mean postoperative BMI was 24.9
. The remarkable findings of adequate glucose control, independent of weight loss, led DePaula to conclude that gastrectomy seemed to be a promising procedure for the control of T2DM.
Caloric restriction, weight loss, and hormonal as well as anatomical changes are some of the major explanations offered as possible mechanisms for improvement in glucose metabolism following surgery. However, the rapid improvement of DM after RYGB counters the argument for weight loss and caloric restriction as these methods require time to achieve proper glycemic control [2
]. Instead, hormonal changes driven by anatomical rearrangement appear to be a more likely theory [3
]. In T2DM, the effects of the incretin hormones, gastric inhibitory peptide (GIP) and glucagon like peptide (GLP), are impaired. GIP enhances the early phase (0–20
min) insulin response to glucose. In addition, GLP enhances both the early and late phases (20–120
min) of the response of insulin to glucose. Not only is there insulin resistance in T2DM, but there is also a loss of the early phase insulin secretion leading to persistent hyperglycemia secondary to the inability to suppress both glucagon secretion and hepatic glucose output. Other documented effects of GLP include a proliferative effect on B cells as well as delayed gastric emptying.
Following RYGB, the effects of GLP are enhanced leading to marked improvements in both glucose metabolism as well as insulin resistance [8
]. This could explain why our patient had rapid glycemic improvements immediately following surgery.