1081. Predictors of Amputation during Hospitalisation with Diabetic Foot Disease: A Prospective Cohort Study 
Session: Poster Abstract Session: Infection in Immunocompromised Patients
Saturday, October 22, 2011
Room: Poster Hall B1
Background: 

Diabetes is the leading cause of lower extremity amputation. Identifying predictors of amputation may allow physicians to recognise those at high risk.  Our objectives were to identify clinical, laboratory and radiological predictors of amputation on admission to hospital with diabetic foot disease.

Methods: 

We performed a prospective cohort study of patients admitted to University Hospital Galway with diabetic foot disease and attended by the multidisciplinary diabetic foot team. The primary outcome variable was lower extremity amputation performed during hospitalisation. The predictor variables were the initial set of clinical, laboratory, and radiological assessments on admission to hospital, including Infectious Diseases Society of America (IDSA) diabetic foot infection classification. Logistic regression analysis was performed using amputation during admission as the binary outcome variable. Predictor variables were analysed using bivariate and multivariate methods, with tests for interaction, and expressed as odds ratios (OR) with 95% confidence intervals (CI).

Results: 

Forty patients were hospitalised with diabetic foot disease during the study period, with 14(35%) patients proceeding to amputation during admission. On bivariate analysis, the presence of osteomyelitis (OR 8.2, 95% CI 1.5, 44.2), higher C-reactive protein levels (OR 1.01/unit increase, 95% CI 1, 1.02), higher white cell count levels (OR 1.2/unit increase, 95% CI 1, 1.4) and increasing severity of IDSA infection classification score (OR 3.8, 95% CI 1.2, 11.9) significantly predicted amputation during admission.  In the multivariate model, higher C-reactive protein (OR 1.03/unit increase, 95% CI 1, 1.05) and higher white cell count (OR 1.89/unit increase, 95% CI 1.07, 3.33) predicted amputation. Amputation was not predicted by haemoglobin-A1c level, foot ulceration, Staphylococcus aureus infection or severity of vascular disease, as measured by toe pressures.

Conclusion: 

Raised markers of infection and the presence of osteomyelitis on admission significantly predicted amputation during hospitalisation with diabetic foot disease.


Subject Category: J. Clinical practice issues

David P Gallagher, MRCPI1, Catherine A Fleming, FRCPI1, Caroline McIntosh, PhD2 and Sean F Dinneen, MD, FRCPI3, (1)Dept of Infectious Diseases, University Hospital Galway, Galway, Ireland, (2)School of Podiatry, NUI Galway, Galway, Ireland, (3)Department of Medicine, NUI Galway, Galway, Ireland

Disclosures:

D. P. Gallagher, None

C. A. Fleming, None

C. McIntosh, None

S. F. Dinneen, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.