Relationship between islet function changes of post-glucose-load and mortality in elderly men with history of hyperglycemia

  Background   The prevalence of diabetes in the elderly is rising in China. The relationship between the islet function changes of post-glucose-load and the prognosis of elderly patients with high risk diabetes remains unclear.

  Objective  To investigate the relationship between islet function changes of post-glucose-load and mortality in elderly patients with high risk diabetes.

  Methods   From May to August in 2005, elderly men aged over than 60 years who did the oral glucose tolerance test (OGTT) owing to an abnormal glucose history were included in the Second Medical Center, Chinese PLA General Hospital. Post-glucose-load islet function changes were assessed with the ratio of (the product of blood glucose plus insulin at 1 hour or 2 hours) to (the product of fasting blood glucose plus FINS). The retrospective follow-up time was up to December 2020, and the death and its time were recorded. Factors affecting 15-year mortality were analyzed and predictive value of the amount of change in 2-hour islet function on 15-year mortality was assessed.

  Results   Totally 220 elderly men were included in the study with an average age of (71.71 ± 7.43) years. During the 15-year follow-up, 67 cases (78.28 ± 5.95 years) died and 153 cases (68.83 ± 6.06 years) survived. Univariate Cox regression revealed that age, diastolic blood pressure, history of respiratory disease, triglycerides, creatinine, glutamate aminotransferase, fasting blood glucose, 2-hour blood glucose, 2-hour insulin, the amount of changes in 2-hour islet function had significant differene between the dead group and the survival group (all P<0.05). Multivariate Cox regression showed that the patients who died were older (HR=1.185, 95% CI: 1.052-1.336), with lower diastolic pressure (HR=0.953, 95% CI: 0.913-0.995) and higher amount of changes in 2-hour islet function (HR=1.020, 95% CI: 1.000-1.040). ROC curve analysis showed that the area under the curve (AUC) of the amount of change in 2-hour islet function was 0.682, and the optimal critical cut-off value was 14.92.

  Conclusion  The changes of islet function at 2 hours after glucose load is an independent factor associated with 15 year mortality risk in elderly men with high-risk diabetes, and the mortality risk increases significantly in people with the level greater than 14.92.