Glucose abnormalities and heart failure predict poor prognosis in the population-based Reykjavik Study

BACKGROUND: The risk of cardiovascular disease increases progressively with increasing blood glucose from levels well below the diabetic threshold. In the Reykjavík Study the relationship between heart failure and abnormal glucose regulation was already apparent at the level of impaired glucose tolerance. The aim of this study was to determine the prognosis of participants with any glucose abnormality and heart failure and to test whether the combination of these conditions may adversely affect the subsequent prognosis. DESIGN: A prospective population-based study. METHODS: Data from the first visit of 19 381 participants were used. Participants were divided into groups according to their glycaemic and heart failure level, and comparisons were made between the groups and disease-free participants serving as a reference group. The risk of mortality and morbidity was calculated with adjustments for main cardiovascular risk factors and ischaemic heart disease. RESULTS: Participants in the reference group were younger, had lower body mass indices and more seldom a history of myocardial infarction compared with diseased groups. Mortality was lowest in the reference group (P<0.0001) increasing to a maximum in participants with the combination of glucose abnormality and heart failure. Prognostically, the mortality risk associated with abnormal glucose regulation was increased but was lower than the risk of diabetes. The risk of a new myocardial infarction was highest in participants with diabetes hazard ratio (HR) 1.6; 95% confidence interval (CI) 1.3-2.0 or diabetes in combination with heart failure (HR 1.8; CI 1.1-2.7). CONCLUSIONS: Heart failure or glucose abnormalities are related to increased morbidity and mortality. The combination of glucose abnormality and heart failure did, however, not add further to the unfavourable prognosis in the presence of ischaemic heart disease.