Effects of platelet-to-lymphocyte ratio on renal function following acute myocardial infarction: A retrospective observational study

Increased platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) in acute myocardial infarction (AMI), which indicate accelerated thrombus formation and inflammatory response, potentially have prognostic implications. Given that cardiovascular disease and renal function exacerbate each other, an elevated PLR and NLR at admission for AMI may worsen renal function after AMI. However, only a few clinical studies have addressed this issue. Therefore, this study aimed to examine the effects of PLR and NLR at AMI onset on renal function. This retrospective study analyzed data from 234 patients hospitalized for AMI. First, correlations between various parameters (age; sex; body mass index; hemoglobin level, albumin level, B-type natriuretic peptide level, C-reactive protein level, creatinine (Cr) level, blood urea nitrogen (BUN) level, PLR, and NLR at admission; contrast medium usage; and maximum creatine kinase) and Cr and BUN levels at discharge were examined using single and multiple regression analyses. Then, correlations between these parameters and the change in Cr (ΔCr) and BUN levels (ΔBUN) were investigated using single and multiple regression analysis, followed by structural equation modeling (SEM). Multiple regression analysis revealed significant positive correlations between PLR at admission and Cr level at discharge (β = 0.135, P = .021), PLR at admission and BUN level at discharge (β = 0.218, P = .006), PLR at admission and ΔCr (β = 0.244, P = .019), and PLR at admission and ΔBUN (β = 0.312, P = .003). SEM results revealed significant positive correlations between PLR at admission and ΔCr (β = 0.260, P = .008) and PLR at admission and ΔBUN (β = 0.292, P = .003). Conversely, NLR demonstrated a minimal association with renal function at discharge compared to PLR. This study suggests that increased PLR at admission in AMI significantly affects and exacerbates renal function but does not increase NLR at admission. PLR is one of the predictors of renal dysfunction after AMI.