Infections Associated With Diabetes

Evidence from centuries of clinical practice supports the relationship between diabetes and infections. Possible mechanisms include the effect of hyperglycemia on the immune system, increased risk of local tissue ischemia, neuropathy, and the association of diabetes with other comorbidities, such as obesity and heart failure, that independently increase the risk of infection. Individuals with diabetes are more likely to develop certain infections compared to those without diabetes, including urinary tract infections (such as asymptomatic bacteriuria, pyelonephritis, renal and perinephric abscess), respiratory tract infections, sepsis, lower extremity infections, deep subcutaneous tissue infections, and tuberculosis. In addition, several rare but serious infections occur almost exclusively in people with diabetes, including necrotizing otitis externa, rhinocerebral mucormycosis, emphysematous pyelonephritis, and Fournier’s gangrene. Though it remains unclear whether diabetes is associated with a higher risk of acquiring COVID-19, evidence suggests diabetes is associated with significantly elevated risk of severe and fatal complications from the infection. In the United States in 1999–2023, the age-standardized percentage of deaths with any infection ranged from 2.3% to 16.8% in persons with diabetes compared with 3.5% to 14.6% in persons without diabetes, with respiratory tract infections accounting for the highest percentage of deaths in both groups. In addition, during 1999–2021, the age-standardized percent of hospital discharges listing any infection ranged from 19.5% to 34.9% in persons with diabetes compared with 12.1% to 23.4% in persons without diabetes. Skin and connective tissue infections were the most common for individuals with diabetes, while respiratory tract infections accounted for the highest percentage of hospital discharges in those without diabetes. Individuals with diabetes who develop infections face higher rates of hospital admission, longer stays, and more complications, which in turn increase healthcare costs. This article summarizes the body of evidence on the relationship between diabetes and infectious disease risks and outcomes. It also outlines implementation strategies to facilitate adoption of evidence-based care for diabetes-related infections.