Mean Platelet Volume-to-Lymphocyte Ratio Is a Biomarker of 1-Year Mortality in Patients With Diabetic Foot Infections

We aimed to evaluate the value of 2 peripheral blood cell ratios, the mean platelet volume-to-lymphocyte ratio (MPVLR) and the neutrophil-to-lymphocyte ratio (NLR) as prognostic biomarkers of mortality in patients with diabetic foot infections (DFIs). We conducted a prospective observational study consisting of a cohort of 200 patients with moderate to severe DFIs consecutively recruited from our Diabetic Foot Unit, Hospital San Juan de Dios, San José de Costa Rica, Costa Rica from October 15, 2020, to December 15, 2021. We studied the variables associated with one-year all-cause mortality using a multivariate backward Cox’s regression model. Nonparametric Spearman Rho was used to study the linear correlation between NLR and MPVLR and other inflammatory markers. The variables associated with all-cause mortality were retinopathy (hazard ratio [HR]: 2.55, 95% confidence interval [CI]: 1.22-5.33, P = .01), estimated glomerular filtration rate (HR: 0.979, 95% CI: 0.969-0.990, P < .001), HbA1c (HR: 0.825, 95% CI: 0.702-0.969, P = .01), and MPVLR (HR: 1.093, 95% CI: 1.020-1.172, P = .01). NLR showed a strong correlation with white blood cell count ( r = 0.60 [<0.001]) and c-reactive protein ( r = 0.63 [<0.001]), and a weak correlation with erythrocyte sedimentation rate ( r = 0.33 [<0.001]), though it was not associated with mortality. In conclusion, apart from other risk factors of mortality, we have for the first time demonstrated that the increasing value of MPVLR is a factor associated with one-year mortality in patients with DFIs.