, Volume 52, Issue 3, pp 415-424
Date: 08 Jan 2009

Continuous relationships between non-diabetic hyperglycaemia and both cardiovascular disease and all-cause mortality: the Australian Diabetes, Obesity, and Lifestyle (AusDiab) study

Abstract

Aims/hypothesis

Hyperglycaemia is a risk factor for cardiovascular disease (CVD) and all-cause mortality in individuals without diabetes. We investigated: (1) whether the risk of all-cause and CVD mortality extended continuously throughout the range of fasting plasma glucose (FPG), 2 h plasma glucose (2hPG) and HbA1c values; and (2) the ability of these measures to improve risk prediction for mortality.

Methods

Data on 10,026 people aged ≥25 years without diagnosed diabetes were obtained from the population-based Australian Diabetes, Obesity and Lifestyle study. Between 1999 and 2000, FPG, 2hPG and HbA1c were assessed and all-cause (332 deaths) and CVD (88 deaths) mortality were obtained after 7 years.

Results

Both 2hPG and HbA1c exhibited linear relationships with all-cause and CVD mortality, whereas FPG showed J-shaped relationships. The adjusted HR (95% CI) for all-cause mortality per SD increase was 1.2 (1.1–1.3) for 2hPG and 1.1 (1.0–1.2) for HbA1c. The HR for FPG <5.1 mmol/l (per SD decrease) was 2.0 (1.3–3.0); for FPG ≥5.1 mmol/l (per SD increase) the HR was 1.1 (1.0–1.2). Corresponding HRs for CVD mortality were 1.2 (1.0–1.4), 1.2 (1.0–1.3), 4.0 (2.1–7.6) and 1.3 (1.1–1.4). The discriminative ability of each measure was similar; no measure substantially improved individual risk identification over traditional risk factors.

Conclusions/interpretation

In individuals without diagnosed diabetes, 2hPG and FPG, but not HbA1c were significant predictors of all-cause mortality, whereas all measures were significant predictors of CVD mortality. However, these glucose measures did not substantially improve individual risk identification.