Is Diabetes Mellitus a Coronary Heart Disease Equivalent? Results of a Meta-Analysis of Prospective Studies

Several guidelines on the treatment of cardiovascular risk factors base their recommendations on the assertion that diabetes mellitus (DM) is a coronary heart disease (CHD) or cardiovascular disease (CVD) risk equivalent. To date, no systematic review of studies substantiating this assertion has been carried out.A systematic search of the PubMed database up to February 2006 was performed to identify prospective studies meeting the following criteria: a) follow-up was >5 years; b) groups of subjects with DM and without CHD (i.e., DM+CHD-), without DM and with CHD (DM-CHD+), and without either DM or CHD (DM-CHD-) were all included; and c) data on CHD or CVD mortality was reported. The characteristics of the studies were assessed, and data were combined separately for men and women using a random effects model and taking the DM-CHD- group as a reference.In total, 13 studies met the inclusion criteria. Overall, CHD mortality was non-significantly lower in DM+CHD- men than in DM-CHD+ men, hazard ratio [HR] (95% confidence interval [CI]), 3.06 (2.45-3.83) vs 4.28 (3.24-5.66), respectively (P=.066); as was CVD mortality, HR (95% CI), 2.55 (2.00-3.26) vs 3.61 (2.81-4.62), respectively (P=.051). In women, there was no significant difference between the DM+CHD- and DM-CHD+ groups with regard to either CHD mortality, HR (95% CI), 4.68 (3.40-6.45) vs 3.51 (1.75-7.04), respectively (P=.42), or CVD mortality, HR (95% CI), 4.70 (4.23-5.22) vs 3.39 (1.51-9.02), respectively (P=.59).The findings of this meta-analysis support the view that women in the DM+CHD- group have similar CHD and CVD mortality to those in the DM-CHD+ group, whereas men in the DM+CHD- group demonstrated a non-significant trend towards lower CHD and CVD mortality than those in the DM-CHD+ group.