Comparison of ESR, CRP and WBC Count as Inflammatory Marker in Patients with Infected and Non-Infected Diabetic Foot

Several clinical, laboratory and imaging modality was suggested for distinguishing infected from non-infected form of diabetic foot ulcer (DFU). This study was performed to compare erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and white blood cell (WBC) count as inflammatory marker in between infected and non-infected diabetic foot ulcer.

A process-research study was conducted on 90 individuals at the Baqiyatallah hospital (Tehran, Iran) between 2009 and 2010. The first group contained infected DFU according to the criteria of IDSA-IWGDF (n=30), second group contained non-infected DFU (n=30) and third group contained healthy individuals (n=30). Demographic, clinical and laboratory (ESR, CRP and WBC count) findings were compared between groups.

The mean and standard deviation (SD) of CRP in healthy, infected and non-infected diabetic foot groups were 1±1.4, 46.5±46.5 and 9.2±5.3 mg/dLit, respectively (p<0.001). The mean±SD of ESR (mm/h) in healthy, infected and non-infected diabetic foot groups were 6.4±6, 76.7±30.1 and 29.1±11.9, respectively (p=0.001) and also, the mean of WBC count in healthy, infected and non-infected diabetic foot groups were 6510±1149, 9846±3662 and 8073±2070 (in 109), respectively (p<0.001). ESR’s area in ROC curve (in diagnosis of infection) was statistically larger than other markers (AUC=0.967) and CRP (AUC=0.871) and WBC count (0.721) was at the next step. The best cut-off point for CRP, ESR and WBC count was 7.1 g/lit, 40.5 mm/h and 7700 per dlit, respectively.

Regarding to the results, although all of these three markers had significant value for predicting the infection, but ESR was introduced as the best independent predicting marker for distinguishing infection because of its higher sensitivity and specificity. Accompanying ESR with CRP or WBC count can increase the predicting value for discrimination of infection.