The association between bacterial infections and the risk of coronary heart disease in type 1 diabetes

Abstract

Background: Diabetes increases the risk of infections and coronary heart disease (CHD). Whether infections increase the risk of CHD and how this applies to individuals with diabetes is unclear.

Objectives: To investigate the association between bacterial infections and the risk of CHD in type 1 diabetes.

Methods: Individuals with type 1 diabetes (n = 3781) were recruited from the Finnish Diabetic Nephropathy Study (FinnDiane), a prospective follow-up study. CHD was defined as incident events: fatal or nonfatal myocardial infarction, coronary artery bypass surgery or percutaneous coronary intervention, identified through national hospital discharge register data. Infections were identified through national register data on all antibiotic purchases from outpatient care. Register data were available from 1 January 1995 to 31 December 2015. Bacterial lipopolysaccharide (LPS) activity was measured from serum samples at baseline. Data on traditional risk factors for CHD were collected during baseline and consecutive visits.

Results: Individuals with an incident CHD event (n = 370) had a higher mean number of antibiotic purchases per follow-up year compared to those without incident CHD (1.34 [95% CI: 1.16-1.52], versus 0.79 [0.76-0.82], P < 0.001), as well as higher levels of LPS activity (0.64 [0.60-0.67], versus 0.58 EU mL^-1 [0.57-0.59], P < 0.001). In multivariable-adjusted Cox proportional hazards models, the mean number of antibiotic purchases per follow-up year was an independent risk factor for incident CHD (HR 1.21, 95% CI: 1.14-1.29, P < 0.0001). High LPS activity was a risk factor for incident CHD (HR 1.93 [1.34-2.78], P < 0.001) after adjusting for static confounders.

Conclusion: Bacterial infections are associated with an increased risk of incident CHD in individuals with type 1 diabetes.

Keywords: bacterial infection; coronary artery disease; diabetes mellitus; diabetic nephropathy.