Risk factors for mortality in patients with diabetic foot infections: a prospective cohort study
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Authors: Lynar SA, Robinson CH, Boutlis CS, Commons RJ
Publication: Internal medicine journal
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An increasing prevalence of diabetes mellitus has led to a high risk of diabetic foot infections (DFI) and associated morbidity. However, little is known about the relationship between DFI and mortality.
To investigate the risk of mortality and associated factors in patients with DFI in an Australian context.
A prospective cohort study of inpatients with DFI between May 2012 and October 2016, at Royal Darwin Hospital, a tertiary referral hospital for the Top End of the Northern Territory. Primary outcome was one‐year mortality with Cox regression analysis undertaken to assess risk factors for mortality.
413 consecutive adult diabetic patients with 737 admissions were referred to the High‐Risk Foot Service for DFI. Cumulative risk of mortality at one year was 8.9% (95%CI 6.4‐12.2). On univariable analysis, mortality was associated with older age (hazard ratio [HR] per year increase 1.08, 95%CI 1.06‐1.11, p=0.001), haemodialysis (HR 3.64, 1.74‐7.62, p<0.001), isolation of Pseudomonas aeruginosa (HR 2.32, 1.05‐5.12, p=0.04), and ischaemic heart disease (HR 2.05, 1.04‐4.07, p=0.04), while Indigenous status (HR 0.48, 0.25‐0.95, p=0.04) and HbA1c>7% (HR 0.45, 0.20‐0.99, p<0.05) were protective. After adjusting for confounders, independent risk factors for mortality were haemodialysis (AHR 5.76, 95%CI 2.28‐14.59, p<0.001) and older age (AHR 1.09, 1.06‐1.13, p<0.001). Patients on haemodialysis had a cumulative risk of mortality of 24.5% (95%CI 14.0‐40.8) at one year.
There is a high risk of mortality associated with DFI, substantially increased in patients undergoing haemodialysis, highlighting the importance of early and dedicated interventions targeted at this high‐risk group.