Mortality differentials by previous diagnosis of diabetes and glycemic status in the United States

Aims: This study examines mortality differences associated with current glycemic status in mortality by current glycemic status among adults with a previously diagnosed diabetes. Using previous clinical diagnosis of diabetes (diagnosed diabetes) and laboratory measures of hemoglobin A1c (HbA1c) measured at baseline, we estimated mortality differentials simultaneously by diagnosed diabetes and baseline glycemic status in the United States. Methods: Data were from 39,491 adults aged 30-84 years assessed in the National Health and Nutrition Exam-ination Survey (NHANES) III and continuous NHANES 1999-2014 linked to mortality data. We categorized participants into four mutually exclusive groups based on diagnosed diabetes and glycemic control measured by HbA1c <= 6.5 % at baseline. Relative hazard ratio (HR) of all-cause death among these four groups were estimated using Cox proportional models. Results: There was no significant difference in mortality by glycemic control status among adults with diagnosed diabetes. The same finding was observed among adults without diagnosed diabetes. Adults with diagnosed diabetes had higher mortality than adults without diagnosed diabetes independent of their baseline glycemic control. Conclusions: Once diagnosed with diabetes, US adults with normal-and hyper-glycemia showed no significant difference in all-cause mortality. This finding emphasizes the importance of primary prevention interventions among adults with a sign of early-stage diabetes.