Postop Care Driven by Bariatric Surgery Method

Bariatric surgery procedures in patients with type 2 diabetes have varying effects on the hormones that control insulin secretion and sensitivity, and these effects must be taken into consideration to maintain glycemic control after surgery, according to a review of bariatric surgery studies that reported diabetes-related outcomes.

“Caloric intake is minimal after any bariatric procedure, and patients are at high risk for hypoglycemia if their preoperative regimens are not appropriately adjusted,” Dr. Marion L. Vetter and her associates at the University of Pennsylvania, Philadelphia, wrote.

Bariatric procedures that have been broadly classified as malabsorptive, such as biliopancreatic diversion (BPD), with duodenal switch have been reported to have greater effect on the gastrointestinal hormones known as incretins (which stimulate insulin release after enteral nutrition) than do so-called restrictive procedures, such as laparoscopic adjustable gastric banding (LAGB) and vertical banded gastroplasty (VBG).

Roux-en-Y gastric bypass (RYGB) incorporates both malabsorptive and restrictive properties. In one large meta-analysis of bariatric studies, type 2 diabetes resolved in 84% of patients after RYGB, whereas it resolved in 98% of patients after BPD and in 48%-72% of patients after LAGB or VBG (Ann. Intern. Med. 2009;150:94-103).

Dr. Vetter and her colleagues found that decreased caloric intake has an immediate impact on insulin sensitivity but does not alone account for lower blood glucose levels because studies have shown that complete diabetes resolution occurs within days of intestinal bypass procedures but takes months to occur after LAGB. Even with the same postoperative caloric intake, blood glucose levels have been shown to drop further and faster after RYGB than after VBG.

Changes in the levels of the incretins called glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), as well as the levels of non-incretin gut peptides known as peptide YY (PYY) and ghrelin, appear to occur rapidly after gastric bypass. GLP-1 is known to slow gastric emptying. It acts on pancreatic ? islet cells to augment glucose-dependent insulin secretion and on the central nervous system to induce satiety and decrease food intake. GLP-1 remains elevated for 1 year after gastric bypass.

GIP is secreted by cells in the proximal gut and also acts on beta islet cells to increase insulin secretion, but it is less potent than GLP-1 and does not affect gastric emptying or satiety. Lower levels of GIP have been reported, albeit inconsistently, several months after RYGB. Studies of restrictive procedures have not found altered GIP levels.

Specialized cells in the distal ileum produce PYY, which increases satiety and delays gastric emptying. PYY is known to increase as early as 2 days after RYGB and remain elevated for at least 6 weeks, which “may account for the immediate decrease in appetite after surgery,” the researchers wrote. The response of PYY is blunted after meals in patients who underwent gastric banding, but no data exist about its level in the weeks after banding or other restrictive procedures.

Because insulin requirements often rapidly decline after bariatric surgery, the authors suggested that “patients may require only long-acting basal insulin in the immediate postoperative period, with rapid-acting insulin for correction of hyperglycemia as necessary.” They recommended avoiding sulfonylureas and meglitinides until patients begin eating regularly. Thiazolidinediones are safe once regular eating is occurring.

The senior author of the review, Dr. Nayyar Iqbal, is employed by Bristol-Myers Squibb. No other authors reported potential financial conflicts of interest.

Bariatric surgery procedures in patients with type 2 diabetes have varying effects on the hormones that control insulin secretion and sensitivity, and these effects must be taken into consideration to maintain glycemic control after surgery, according to a review of bariatric surgery studies that reported diabetes-related outcomes.

“Caloric intake is minimal after any bariatric procedure, and patients are at high risk for hypoglycemia if their preoperative regimens are not appropriately adjusted,” Dr. Marion L. Vetter and her associates at the University of Pennsylvania, Philadelphia, wrote.

Bariatric procedures that have been broadly classified as malabsorptive, such as biliopancreatic diversion (BPD), with duodenal switch have been reported to have greater effect on the gastrointestinal hormones known as incretins (which stimulate insulin release after enteral nutrition) than do so-called restrictive procedures, such as laparoscopic adjustable gastric banding (LAGB) and vertical banded gastroplasty (VBG).

Roux-en-Y gastric bypass (RYGB) incorporates both malabsorptive and restrictive properties. In one large meta-analysis of bariatric studies, type 2 diabetes resolved in 84% of patients after RYGB, whereas it resolved in 98% of patients after BPD and in 48%-72% of patients after LAGB or VBG (Ann. Intern. Med. 2009;150:94-103).

Dr. Vetter and her colleagues found that decreased caloric intake has an immediate impact on insulin sensitivity but does not alone account for lower blood glucose levels because studies have shown that complete diabetes resolution occurs within days of intestinal bypass procedures but takes months to occur after LAGB. Even with the same postoperative caloric intake, blood glucose levels have been shown to drop further and faster after RYGB than after VBG.

Changes in the levels of the incretins called glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), as well as the levels of non-incretin gut peptides known as peptide YY (PYY) and ghrelin, appear to occur rapidly after gastric bypass. GLP-1 is known to slow gastric emptying. It acts on pancreatic ? islet cells to augment glucose-dependent insulin secretion and on the central nervous system to induce satiety and decrease food intake. GLP-1 remains elevated for 1 year after gastric bypass.

GIP is secreted by cells in the proximal gut and also acts on beta islet cells to increase insulin secretion, but it is less potent than GLP-1 and does not affect gastric emptying or satiety. Lower levels of GIP have been reported, albeit inconsistently, several months after RYGB. Studies of restrictive procedures have not found altered GIP levels.

Specialized cells in the distal ileum produce PYY, which increases satiety and delays gastric emptying. PYY is known to increase as early as 2 days after RYGB and remain elevated for at least 6 weeks, which “may account for the immediate decrease in appetite after surgery,” the researchers wrote. The response of PYY is blunted after meals in patients who underwent gastric banding, but no data exist about its level in the weeks after banding or other restrictive procedures.

Because insulin requirements often rapidly decline after bariatric surgery, the authors suggested that “patients may require only long-acting basal insulin in the immediate postoperative period, with rapid-acting insulin for correction of hyperglycemia as necessary.” They recommended avoiding sulfonylureas and meglitinides until patients begin eating regularly. Thiazolidinediones are safe once regular eating is occurring.

The senior author of the review, Dr. Nayyar Iqbal, is employed by Bristol-Myers Squibb. No other authors reported potential financial conflicts of interest.

Bariatric surgery procedures in patients with type 2 diabetes have varying effects on the hormones that control insulin secretion and sensitivity, and these effects must be taken into consideration to maintain glycemic control after surgery, according to a review of bariatric surgery studies that reported diabetes-related outcomes.

“Caloric intake is minimal after any bariatric procedure, and patients are at high risk for hypoglycemia if their preoperative regimens are not appropriately adjusted,” Dr. Marion L. Vetter and her associates at the University of Pennsylvania, Philadelphia, wrote.

Bariatric procedures that have been broadly classified as malabsorptive, such as biliopancreatic diversion (BPD), with duodenal switch have been reported to have greater effect on the gastrointestinal hormones known as incretins (which stimulate insulin release after enteral nutrition) than do so-called restrictive procedures, such as laparoscopic adjustable gastric banding (LAGB) and vertical banded gastroplasty (VBG).

Roux-en-Y gastric bypass (RYGB) incorporates both malabsorptive and restrictive properties. In one large meta-analysis of bariatric studies, type 2 diabetes resolved in 84% of patients after RYGB, whereas it resolved in 98% of patients after BPD and in 48%-72% of patients after LAGB or VBG (Ann. Intern. Med. 2009;150:94-103).

Dr. Vetter and her colleagues found that decreased caloric intake has an immediate impact on insulin sensitivity but does not alone account for lower blood glucose levels because studies have shown that complete diabetes resolution occurs within days of intestinal bypass procedures but takes months to occur after LAGB. Even with the same postoperative caloric intake, blood glucose levels have been shown to drop further and faster after RYGB than after VBG.

Changes in the levels of the incretins called glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), as well as the levels of non-incretin gut peptides known as peptide YY (PYY) and ghrelin, appear to occur rapidly after gastric bypass. GLP-1 is known to slow gastric emptying. It acts on pancreatic ? islet cells to augment glucose-dependent insulin secretion and on the central nervous system to induce satiety and decrease food intake. GLP-1 remains elevated for 1 year after gastric bypass.

GIP is secreted by cells in the proximal gut and also acts on beta islet cells to increase insulin secretion, but it is less potent than GLP-1 and does not affect gastric emptying or satiety. Lower levels of GIP have been reported, albeit inconsistently, several months after RYGB. Studies of restrictive procedures have not found altered GIP levels.

Specialized cells in the distal ileum produce PYY, which increases satiety and delays gastric emptying. PYY is known to increase as early as 2 days after RYGB and remain elevated for at least 6 weeks, which “may account for the immediate decrease in appetite after surgery,” the researchers wrote. The response of PYY is blunted after meals in patients who underwent gastric banding, but no data exist about its level in the weeks after banding or other restrictive procedures.

Because insulin requirements often rapidly decline after bariatric surgery, the authors suggested that “patients may require only long-acting basal insulin in the immediate postoperative period, with rapid-acting insulin for correction of hyperglycemia as necessary.” They recommended avoiding sulfonylureas and meglitinides until patients begin eating regularly. Thiazolidinediones are safe once regular eating is occurring.

The senior author of the review, Dr. Nayyar Iqbal, is employed by Bristol-Myers Squibb. No other authors reported potential financial conflicts of interest.