Role of Procalcitonin as a Predictor of Clinical Outcome in Acute Diabetic Foot Infections: A Prospective Study

Abstract

Background: Prediction of outcome in diabetic foot infection (DFI) remains difficult due to lack of active signs of infection, and apparently normal white blood cell (WBC) count. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) have been studied previously in this regard and were not useful. Hence, we evaluated procalcitonin (PCT) as a prognostic marker in this study.

Objectives: We aimed to study the role of PCT, CRP, and ESR levels in predicting clinical outcome of acute DFI.

Materials and methods: A total of 250 subjects (197 men, 53 women) with acute DFI were enrolled. WBC count, ESR, CRP, and PCT were done for all subjects at admission after obtaining informed consent. Subjects were managed according to hospital protocol and followed up for 1 month. Clinical outcome was assessed based on mobility and morbidity status of the subject.

Results: Old age, anemia, hyponatremia, hypoalbuminemia, and elevated serum creatinine were risk factors for poor outcome. Presence of cardiac failure, diabetic retinopathy, peripheral vascular disease, previous amputations, and positive bone culture had negative influence on clinical outcome. Elevated WBC count, ESR, CRP, and serum PCT were significantly associated with bad outcome. Elevated PCT (>2 ng/ml) [odds ratio (OR) (95% confidence interval (CI)), 2.03 (1.13-5.19), P < 0.001], gangrene [OR (95% CI), 2.2 (1.02-4.73), P = 0.04], and sepsis [OR (95% CI), 10.101 (4.34-23.25), P < 0.001] were good predictors of clinical outcome in acute DFI.

Conclusion: PCT proved to be a reliable marker of acute DFI and good predictor of clinical outcome than existing markers WBC count, ESR, and CRP. Hence it should be useful for clinicians while managing acute DFI.

Keywords: C-reactive protein; diabetic foot infection; erythrocyte sedimentation rate; procalcitonin.

Figure 1

Factors predicting clinical outcome in acute DFIs by forest plot analysis

Figure 2

PCT predicted clinical outcome in acute DFI (AUC 0.807, P < 0.001) with 80% sensitivity and 75% specificity for a value of 0.583 ng/ml