Obesity and dysglycemia are major risk factors for type 2 diabetes. We sought to determine if substantial, sustained weight loss prevented obese people progressing from impaired fasting glucose (IFG) to diabetes.
Research design and methods
Obese people with IFG who underwent laparoscopic adjustable gastric banding (LAGB) between 1995 and 2007 at one Melbourne centre were identified from a prospective database and followed for at least four years. Weight change and onset of diabetes were measured and these outcomes compared to those of a contemporaneous group of Australian adults with IFG who were followed for five years (AusDiab study).
We identified 318 LAGB patients with IFG at the time of surgery. Their mean±sd age and body mass index were 45.4±9.7 years and 45.7±8.6kg/m2 respectively. After 6.1±1.7 years, the majority sustained substantial weight loss of greater than 45% excess body weight (EBW). The degree of weight loss correlated with diabetes incidence, which was 42 cases/1000 person-years in people who lost no more than 20% EBW and less than 2 cases/1000 person-years in those losing greater than 45% EBW. In the AusDiab cohort, BMI was substantially lower (28.4±5.1kg/m2) and diabetes incidence was 12 cases/1000 person-years. This increased to 20 cases/1000 person-years when analysis was restricted to 322 obese AusDiab participants, a rate significantly higher than the overall rate of 8 cases/1000 person-years seen in the LAGB group. Multivariable analysis of the combined LAGB and AusDiab data revealed LAGB reduced the 5-year risk of diabetes by more than 75% (odds ratio [95% CI]: 0.239 [0.095-0.571], p=0.004).
In obese people with IFG, weight loss following LAGB reduces the risk of developing diabetes over five years. Further study of the role of bariatric surgery to prevent diabetes in obese people with IFG is warranted.