Pilot study of the diagnostic value of CRP:albumin ratio for osteomyelitis in patients with diabetic foot ulcers

Abstract

Objective: Osteomyelitis may complicate diabetic foot ulcers (DFUs). As a new inflammation-based prognostic factor, CRP:albumin ratio's significance is not known in osteomyelitis among patients with or without diabetes. Method: Patients with type 2 diabetes and DFUs were divided into two groups: group 1 (n=47) comprised patients without osteomyelitis, and group 2 (n=50) comprised patients with osteomyelitis. Results: Erythrocyte sedimentation rate (ESR) (88.5±23.0 versus 42.0±22.2), white blood cell count (WBC) (14.7±6.9x103 versus 10.0±4.4x103), C-reactive protein (CRP) level (15.6±9.9 versus 2.4±3.3) and CRP:albumin ratio (6.6±4.9 versus 0.7±1.0) were significantly higher, and albumin level was significantly lower in group 2 compared to group 1 (p<0.001 for all). The presence of osteomyelitis was significantly and positively correlated with ESR (r=0.721; p<0.001), WBC (r=0.380; p<0.001), CRP (r=0.667; p<0.001) and CRP:albumin ratio (r=0.638; p<0.001), and negatively correlated with albumin (r=−0.590; p<0.001). A CRP:albumin ratio of 1.74 or above could predict osteomyelitis with 92.0% sensitivity, 80.9% specificity, and the best area under the curve (AUC) score (AUC=0.957; 95% CI: 0.924–0.991). ESR (odds ratio (OR): 1.071 (1.025–1.119); p=0.02) and CRP:albumin ratio (OR: 2.65 (1.437–4.885); p=0.002) were independent predictors in the final model for stepwise linear regression analyses for the estimation of osteomyelitis. Conclusion: CRP:albumin ratio is a cheap and repeatable inflammatory marker and can successfully detect osteomyelitis in patients with DFU.