RESEARCH ARTICLE Impaired Glucose Metabolism among Those with and without Diagnosed Diabetes and Mortality: A Cohort Study Using Health Survey for England Data

Background The extent that controlled diabetes impacts upon mortality, compared with uncontrolled dia-betes, and how pre-diabetes alters mortality risk remain issues requiring clarification. Methods We carried out a cohort study of 22,106 Health Survey for England participants with a HbA1C measurement linked with UK mortality records. We estimated hazard ratios (HRs) of all-cause, cancer and cardiovascular disease (CVD) mortality and 95 % confidence intervals (CI) using Cox regression. Results Average follow-up time was seven years and there were 1,509 deaths within the sample. Compared with the non-diabetic and normoglycaemic group (HbA1C<5.7 % [<39mmol/ mol] and did not indicate diabetes), undiagnosed diabetes (HbA1C6.5 % [48mmol/mol] and did not indicate diabetes) inferred an increased risk of mortality for all-causes (HR 1.40, 1.09–1.80) and CVD (1.99, 1.35–2.94), as did uncontrolled diabetes (diagnosed diabete