The Infected Diabetes-related Foot: Comparison of CRP/Albumin and ESR/Albumin Ratios with ESR and CRP to Differentiate Bone and Soft Tissue Infections.

The objective of this study was to evaluate the effectiveness of CRP/Albumin, ESR/Albumin Ratio, ESR, CRP and albumin to differentiate bone and soft tissue infection in persons with diabetes. We retrospectively evaluated 242 individuals admitted to hospital with diabetes-related foot infections (DFI). We categorized DFI cases as either bone (OM) or soft tissue infection (STI) based on bone culture and/or histology. We evaluated the diagnostic accuracy of CRP, ESR, Albumin, CRP/Albumin and ESR/Albumin as biomarkers to diagnose OM in persons with diabetes. The median age was 53 years (74% male). There were 224 diabetes-related patients of which 125 had been diagnosed with osteomyelitis. The ESR/Albumin and CRP/Albumin ratios cut-points were > 17.84 and > 1.83, respectively. ESR/Albumin and CRP/Albumin ratios had similar diagnostic parameters: AUC (0.71, 0.71), sensitivity (70.0%, 57.0%), specificity (62.0%, 75.0%), positive predictive value (67.0%, 71.0%) and negative predictive value (66.0% and 71.0%). In contrast diagnostic efficiency of CRP and ESR were AUC 0.71 and 0.71, sensitivity (45.6%, 71.2%), specificity (85.5%, 60.7%), positive predictive value (70.0%, 65.9%), and negative predictive value (59.5%, 66.4%), respectively. When comparing area under the curves, the results showed that ESR/Albumin was not significantly different to ESR alone (Delong test p vs ESR > 0.1). Similarly, CRP/Albumin was not significantly different to CRP alone (Delong test p vs CRP > 0.1). In conclusion, ESR/Albumin and CRP/Albumin ratios provided comparable results as using ESR and CRP alone. This article is protected by copyright. All rights reserved.