Relationship between blood glucose level and mortality in Type 2 diabetes mellitus: a systematic review

AIM: To review the relationship between blood glucose level and mortality in patients with Type 2 diabetes mellitus (DM) as reported in the literature. METHODS: Literature search using Medline Search: January 1966 - April 1998. KEYWORDS: Diabetes, Non Insulin Dependent, Mortality. Inclusion criteria for papers were: Type 2 DM; follow-up for at least 3 years; glucose or glycated haemoglobin (HbA1c) was used as parameter; published in the form of an article. Additionally all references in the selected articles that dealt with the relationship between blood glucose level and mortality in Type 2 DM were included in the search. RESULTS: Twenty-seven eligible articles were found. Twenty-three of them showed a positive association: measures of elevated blood glucose concentrations were associated with higher mortality; in 15 out of 23 studies the positive association was statistically significant, in two only for postprandial blood glucose. One study found a nonsignificant negative relationship in a very old population. CONCLUSION: In the literature there is a positive, but rather weak, association between the measures of blood glucose control and the risk of dying of patients with Type 2 DM. In the six larger studies (more than 100 deceased patients) that used a continuous categorization of glycaemia, the Risk ratio per unit varies from 1.03 to 1.12.