Predicting diabetic foot ulcer infection using the neutrophil-to-lymphocyte ratio: a prospective study

To investigate whether the neutrophil-to-lymphocyte ratio (NLR) may be used in the early stage risk assessment and follow-up in diabetic foot infection.

Over a five-year study, NLR values on admission and day 14 of treatment were matched with their laboratory and clinical data in a cohort study. Patients were followed-up or consulted in several clinics or polyclinics (infectious diseases).

Admission time NLR was higher, in severe cases as indicated by both Wagner and PEDIS infection scores (severe versus mild Wagner score NLR 6.7 versus 4.2; p=0.04; for PEDIS score NLR 6.3 versus 3.6; p=0.03, respectively). In patients who underwent vascular intervention (12.6 versus 4.6; p=0.02); amputation indicated (9.2 versus 4.1; p=0.005) and healed afterwards (6.9 versus 4.3; p<0,001), when matched with others. NLR was also found to be correlated with duration of both IV antibiotic treatment (r=0.374; p=0.005) and hospitalisation (r=0.337; p=0.02). Day 14 NLR was higher in patients who underwent vascular intervention (5.1 versus 2.9; p=0.007) when matched to others.

Patients with higher NLR values at admission had more severe diabetic foot infection, higher risk for amputation, need for long-term hospitalisation and aggressive treatment. However, they also have more chance of benefit from treatment.