Association between random glucose and all-cause mortality: findings from the mortality follow-up of the German National Health Interview and Examination Survey 1998

BACKGROUND: Random glucose is widely measured in epidemiological studies and in the clinical setting when standardized fasting protocols and oral glucose tolerance testing or HbA(1c) measuring are not feasible. The relationship between random glucose and all-cause mortality has hardly been studied so far and was examined in the present study. METHODS: We ascertained mortality status among 5955 persons aged 18–79 years and free of known diabetes when participating in the German National Health Interview and Examination Survey 1998 (mean observation time 11.7 years, 458 deaths). Cox regression was applied to analyze the association of random serum glucose with all-cause mortality taken potential confounders into account. Relative mortality risks were estimated as hazard ratios (HRs) with 95% confidence intervals (CIs) modeling random glucose as categorical or continuous variable. RESULTS: Compared to random glucose levels of 4.3 - < 5.3 mmol/L, HRs (95% CIs) were 1.94 (0.85–4.45) for levels < 4.3 mmol/L and 1.16 (0.89–1.50), 1.20 (0.91–1.58), 1.42 (0.88–2.29), 2.02 (1.26–3.25) and 4.71 (2.20–10.10) for levels 5.3 - < 5.8, 5.8 - < 6.8, 6.8 - < 7.8, 7.8 - < 11.1 and ≥ 11.1 mmol/L, adjusted for age, sex, lifestyle, anthropometry and chronic diseases. An additional adjustment for fasting time or HbA(1c) yielded similar estimates. Modeling continuous random glucose by restricted cubic spline functions revealed comparable findings. CONCLUSIONS: In the present epidemiological study drawn from the general population, random glucose showed a significant association with all-cause mortality, independent of main potential confounders. Thus, random glucose measures are highly relevant to health risk assessment among people without known diabetes when fasting glucose or HbA(1c) are difficult to obtain. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12902-018-0319-2) contains supplementary material, which is available to authorized users.