Mortality Risk in Spanish Adults With Diagnosed Diabetes, Undiagnosed Diabetes or Pre-Diabetes. The Asturias Study 1998-2004

Introduction and objectives. Although type-2 diabetes is a well-known cause of death, the mortality associated with undiagnosed diabetes and early-stage dysglycemia has not been clearly determined. Methods. This study included 1015 individuals aged 30-75 years who took part in the first phase of the Asturias study (1998-1999). Participants completed a questionnaire and underwent a physical examination and an oral glucose tolerance test (OGTT). All deaths that occurred in the cohort within 6 years of follow-up (i.e. December 1998 to December 2004) were recorded. Results. Participants were divided into four groups according to the condition indicated by their OGTT result in the first phase of the study: normoglycemia, pre-diabetes, undiagnosed diabetes or diagnosed diabetes (World Health Organization 1999 criteria). A total of 42 deaths were recorded during follow-up. With normoglycemic individuals acting as a control group, multivariate analysis showed that the relative risk of mortality was 2.5 (95% CI, 1-6.3) in the group with diagnosed diabetes, 2.7 (95% CI, 1.1-6.7) in the group with undiagnosed diabetes and 1.6 (95% CI, 0.7-4) in the group with pre-diabetes. Conclusions. Both individuals with diagnosed diabetes and those with undiagnosed diabetes had a risk of mortality around 2.5-3 times greater than individuals with normoglycemia. Those with pre-diabetes also had increased mortality relative to the control group, though the difference was not significant.