Diabetes and mortality risk in patients undergoing coronary angiography: The KARDIO study.

Background: Diabetes is an established risk factor for adverse cardiovascular outcomes including mortality, but the relationship between diabetes and mortality risk in the presence of the extensive or diffuse form of coronary artery disease (CAD) is controversial.

Aims: We evaluated the association between diabetes and mortality risk in patients who underwent coronary angiography using a real-life clinical database.

Methods: We utilized the KARDIO registry, which comprised data on demographics, prevalent diseases, including diabetes status, cardiovascular risk factors, coronary angiographies, and other interventions in 79,738 patients. Hazard ratios (HRs) (95% confidence intervals [CIs]) for the association between prevalent diabetes and all-cause mortality were estimated.

Results: During a median follow-up of 5.5 years, 11,896 all-cause deaths occurred. In analyses adjusted for age, smoking status, hypertension, family history of CAD, dyslipidaemia, urgency of intervention, body mass index, sex, and sex-age interaction, the HR (95% CI) for mortality comparing diabetes with no diabetes was 1.44 (1.38, 1.50). Following additional adjustment for the degree of CAD (1-3 vessels disease) as confirmed by angiography, the HR (95% CI) for mortality remained similar 1.43 (1.36, 1.49). The association did not vary significantly across several relevant clinical characteristics except for a stronger association in those with a family history of CAD than those without (p = 0.034) and former smokers than nonsmokers (p = 0.046).

Conclusion: In patients undergoing coronary angiography, diabetes is associated with an increased mortality risk, independent of several risk factors including the degree of CAD. The association may be modified by family history of CAD and smoking status.