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.

The infected diabetes‐related foot: Comparison of erythrocyte sedementation rate/albumin and C‐reactive protein/albumin ratios with erythrocyte sedimentation rate and C‐reactive protein to differentiate bone and soft tissue infections

“…They evaluated ESR, CRP, WBC, CRP/albumin ratio to diagnoses OM. CRP/albumin had the highest AUC; however, CRP and ESR and albumin were also effective to identify OM 10 …”

“…29 We were only able to identify two studies that used CRP/albumin ratio in diabetes-related foot infections. 10,30 In a retrospective cohort study, Aragon-Sanchez and colleagues evaluated 245 patients with moderate and severe diabetes-related foot infections. They used SIRS criteria to determine severe infections 13 and CRP, ESR, CRP/Albumin, albumin and neutrophil to lymphocyte ratio as biomarkers to predict severe infection.…”

“…CRP/albumin had the highest AUC; however, CRP and ESR and albumin were also effective to identify OM. 10 Albumin is an inflammatory marker that decreases when there is systemic inflammation. In the past, low albumin levels were thought to be markers of poor nutrition, and several authors reported their association with an increased risk of poor healing, leg amputation and death.…”

“…We were only able to identify two studies that used CRP/albumin ratio in diabetes‐related foot infections 10,30 . In a retrospective cohort study, Aragon‐Sanchez and colleagues evaluated 245 patients with moderate and severe diabetes‐related foot infections.…”

“…5 Previous studies have also described the utility of ESR and CRP in monitoring OM. 6,7 Recently, several authors have evaluated the ratio of CRP and albumin to identify total joint infections, 8 infection versus inflammation in patients with systemic lupus erythematosus 9 and OM in diabetes-related foot infections 10 as well as to predict death. 11,12 The goal of this study was to evaluate CRP/albumin and ESR/albumin ratios to diagnose OM to determine if they improved on the diagnostic characteristics of ESR and CRP alone.…”