People with type 2 diabetes are up to 55% more likely to experience hospital-treated infections and up to 30% more likely to receive an antibiotic prescription in the community setting, compared with the general population, but these associations moderated over an 8-year period – a phenomenon that could be at least partly related to better treatment of diabetes and an overall improvement in mean blood glucose levels, according to results of a large population-based study.
“These findings may be driven by earlier detection and treatment of milder type 2 diabetes cases over time,” or by improved therapy of hyperglycemia and other risk factors, wrote Anil Mor, MD, of Aarhus University Hospital, Denmark, and his associates (Clin Infect Dis. 2016 June 26. doi: 10.1093/cid/ciw345).
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The study ran from 2004 to 2012 and used data from the Danish National Patient Registry. It tracked community- and hospital-treated infections in approximately 774,017 controls; of these, 155,158 had type 2 diabetes. Patients with diabetes were more likely to have serious medical comorbidities compared with controls (29% vs. 21%). These included myocardial infarction (5% vs. 3%), heart failure (4% vs. 2%), cerebrovascular diseases (7% vs. 5%), peripheral vascular diseases (4% vs. 2%), and chronic pulmonary disease (6% vs. 2%).
Over the study period, 62% of the diabetes patients received an antibiotic, compared with 55% of the controls – a 24% increased relative risk in a model that adjusted for factors such as alcohol use, Charlson comorbidity index, and cardiovascular and renal comorbidities. Cephalosporins were the most commonly prescribed drugs, followed by antimycobacterial agents, quinolones, and antibiotics commonly used for urinary tract and Staphylococcus aureus infections.
Hospital-treated infections were significantly more common among patients with diabetes, with 19% having at least one such infection compared with 13% of controls (RR 1.55). On a larger scale, at a median follow-up of 2.8 years, the hospital-treated rate among diabetes patients was 58 per 1,000 person/years vs. 39 per 1,000 person/years among controls – a relative risk of 1.49.
Patients were at highest risk for emphysematous cholecystitis (adjusted rate ratio 1.74) and abscesses, tuberculosis, and meningococcal infections. Pneumonia was approximately 30% more likely among patients.
The risk of a hospital-treated infection was highest among younger patients aged 40-50 years (RR 1.77) and lowest among those older than 80 years (RR 1.29). It was also higher among those with higher comorbidity scores. Statin use appeared to attenuate some of the risk, the authors noted. The authors did not discuss the possible cause of this association.
The annual risk of a hospital-treated infection among patients declined from a high of 1.89 in 2004 to 1.59 in 2011. The risk of receiving a community-based antibiotic prescription declined as well, from 1.31 in 2004 to 1.26 in 2011.
These changes were not seen in the control group, suggesting that patients with diabetes were experiencing a unique improvement in infections – earlier detection and treatment of type 2 diabetes, and better comorbidity management could be explanations, the investigators speculated.
The study was sponsored by the Danish Centre for Strategic Research in Type 2 Diabetes and the Program for Clinical Research Infrastructure established by the Lundbeck Foundation and the Novo Nordisk Foundation. Several of the coauthors reported financial ties with various pharmaceutical companies.