• As many as 90% of patients had improved glucose control following bariatric surgery, investigators told attendees at the American Society of Metabolic and Bariatric Surgery.

"Beyond three years after Roux-en-Y gastric bypass there is a significant cohort of patients that experiences recurrence or worsening of their diabetes after an initial period of resolution or improvement," said Daniel Rosen, MD, of Columbia University in New York. "Poor weight loss and more weight regain were seen in the recurrence/worsening group."

"Before widespread acceptance and implementation of bariatric surgery as definitive treatment for diabetes, further study of this recurrence phenomenon is indicated."

Roux-en-Y gastric bypass led to early resolution of diabetes in 153 of 172 (89%) obese patients with type 2 diabetes, said Silas Chikunguwo, MD, of Virginia Commonwealth University in Richmond.

Patients who had complete resolution of diabetes had lost an average 70% of excess weight, and their mean body mass index (BMI) decreased from 50 to 31. The remaining 19 patients had persistent diabetes despite excess weight loss that averaged 58%, said Dr. Chikunguwo.

During follow-up of five to 16 years, 66 of the 153 patients (43.1%) had recurrence of diabetes, which was associated with weight regain.

Mean excess weight loss declined from 66% to 48.9% in patients who had recurrent disease.

"Long-term weight control appears important for durable resolution of type 2 diabetes," said Dr. Chikunguwo.

Data from New York University showed that 53% of patients with type 2 diabetes remained medication free five years after undergoing laparoscopic adjustable gastric banding.

In addition, the proportion of patients requiring oral hypoglycemic agents declined from 75% before the procedure to 39% at five years, said NYU's Samuel Sultan. Overall, 80% of the patients were medication free or on lower doses.

The analysis comprised 95 morbidly obese patients with type 2 diabetes who had weight-loss surgery from 2002 to 2004. Median and mean follow-up was five years.

Excess weight loss at five years averaged 48.3%. Mean BMI decreased from 46.3 at baseline to 35 (P<0.001), fasting glucose from 146 to 118.5 mg/dL (P=0.004), and hemoglobin A1c from 7.53% to 6.58% (P<0.001).

However, only 40% of patients met criteria for diabetes remission at five years: off all medication and either an HbA1c less than 6% or a blood glucose level less than 100 mg/dL.

Lack of diabetes remission at five years was associated with significantly lower excess weight loss (38.2% versus 57.3%, P=0.001).

Dr. Rosen presented data from a retrospective analysis of long-term results in 42 morbidly obese patients who had type 2 diabetes prior to gastric bypass surgery. The primary objective was to characterize patients who achieved long-term resolution of diabetes with those who improved but were not in remission.

Follow-up averaged five years, and all patients had been followed for at least three years.

He and his team defined resolution of diabetes as being off all diabetes medications plus either an HbA1c less than 6% or blood glucose less than 124 mg/dL. They defined improvement as a decrease in medication requirements.

Dr. Rosen said 27 patients met criteria for resolution after surgery and 15 were improved.

The high point for mean excess weight loss was 58.3%, and regained weight averaged 21%. Nine patients had weight-loss failure, defined as <50% excess weight loss.

Diabetes resolution was associated with slightly greater peak excess weight loss (61% versus 52%), fewer weight-loss failures, and lower baseline HbA1c and blood glucose levels.

Patients who had resolution of diabetes were significantly more likely to be on oral medications (P=0.0006), whereas significantly more patients who improved were on insulin preoperatively (P<0.0001).

During follow-up, 10 patients (24%) had either recurrence or worsening of diabetes.

Compared with patients who had no change in diabetes status at five years, recurrence and worsening were associated with:

• Lower preoperative BMI (P=0.05)
• Higher rate of weight loss failure (P=0.03)
• Higher percentage of weight regained (P=0.002)
• Higher postoperative blood glucose values (P=0.0002)

The reasons for diabetes recurrence are not entirely clear, said Dr. Rosen, but failure of the surgical procedure over time probably is not the cause. Upper gastrointestinal evaluations in five of seven patients with recurrence revealed no abnormalities.