Association of Platelet-to-lymphocyte Ratio with Kidney Clinicopathologic Features and Renal Outcomes in Patients with Diabetic Kidney Disease

Background: Growing evidence points to the pivotal role of inflammation in the pathogenesis of diabetic kidney disease (DKD). However, as an inflammation-based prognostic score, the significance of platelet-to-lymphocyte ratio (PLR) in biopsy-proven DKD remains uncertain. Therefore, the current study aimed to evaluate the association of PLR with the clinicopathological features and the progression of DKD.

Methods: In total, 167 patients with biopsy-proven T2DKD were retrospectively recruited. Clinicopathological characteristics were compared according to the tertiles of baseline PLR. Pearson's or Spearman correlations were used to examine the associations between PLR and baseline characteristics. Assessment of the prospective relationship of PLR with the kidney outcomes defined as a doubling of baseline serum creatinine or onset of end stage renal disease (ESRD), were investigated by Kaplan-Meier survival analysis. Moreover, a cubic spline curve was further calculated to explore the significance of PLR in DKD prognosis. On top of that, identification of the risk factors associated with DKD progression was executed by a model of Cox proportional hazards.

Results: Median follow-up period was 23.77 months, during which 92 (55.1%) patients confronted DKD progression. Pearson's correlation indicated that urinary protein increased along with PLR rising (r = 0.193, P = 0.012). Kaplan-Meier survival curves revealed a significantly increased probability of event-free survival in the lowest tertile of PLR compared to those in the highest tertile (P = 0.018). A statistical linear correlation between PLR and DKD development was demonstrated by a restricted cubic spline analysis (P for nonlinear = 0.784). In addition, the analyses of multivariate Cox regression indicated that elevated PLR had an association with a greater risk of DKD progression (HR 1.004, 95%CI [1.000-1.008], P = 0.035), which was verified to be an independent risk factor for renal outcomes.

Conclusions: Our findings demonstrated that the PLR was associated with proteinuria and prognosis in DKD patients. It was an independent risk factor for kidney progression in biopsy-proven DKD.