Bacterial infections in patients with type 1 diabetes: a 14-year follow-up study

OBJECTIVE: This study explored the annual occurrence/incidence of bacterial infections, and their association with chronic hyperglycemia and diabetic nephropathy, in patients with type 1 diabetes. DESIGN: In a register-based follow-up study, we investigated the frequency of bacterial infections in patients with type 1 diabetes (n=4748) and age-matched and sex-matched non-diabetic control (NDC) subjects (n=12 954) using nationwide register data on antibiotic drug prescription purchases and hospital discharge diagnoses, collected between 1996 and 2009. Diabetic nephropathy was classified based on the urinary albumin excretion rate (AER). RESULTS: The hospitalization rate due to bacterial infections was higher in patients with diabetes compared with NDCs (rate ratio (RR) 2.30 (95% CI 2.11 to 2.51)). The rate correlated with the severity of diabetic nephropathy: RR for microalbuminuria was 1.23 (0.94 to 1.60), 1.97 (1.49 to 2.61) for macroalbuminuria, 11.2 (8.1 to 15.5) for dialysis, and 6.72 (4.92 to 9.18) for kidney transplant as compared to patients with diabetes and normal AER. The annual number of antibiotic purchases was higher in patients with diabetes (1.00 (1.00 to 1.01)) as compared with NDCs (0.47 (0.46 to 0.47)), RR=1.71 (1.65 to 1.77). Annual antibiotic purchases were 1.18-fold more frequent in patients with microalbuminuria, 1.29-fold with macroalbuminuria, 2.43-fold with dialysis, and 2.74-fold with kidney transplant as compared to patients with normal AER. Each unit of increase in glycated hemoglobin was associated with a 6–10% increase in the number of annual antibiotic purchases. CONCLUSIONS: The incidence of bacterial infections was significantly higher in patients with type 1 diabetes compared with age-matched and sex-matched NDC subjects, and correlated with the severity of diabetic nephropathy in inpatient and outpatient settings.