Platelet-to-lymphocyte ratio and prognosis in STEMI: A meta-analysis

Platelet-to-lymphocyte ratio (PLR) is a haematological index which reflects increased level of inflammation and thrombosis. We aimed to summarize the potential prognostic role of PLR for the in-hospital and long-term outcomes in ST-segment elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (pPCI) in a meta-analysis.

Relevant cohort studies were identified by search the PubMed, Cochrane's Library and Embase databases. A random-effect model was applied to pool the results. In-hospital and long-term outcomes were compared between patients with higher and lower preprocedural PLR.

Eleven cohorts with 12 619 patients were included. Pooled results showed that higher preprocedural PLR was independently associated with increased risk of in-hospital major adverse cardiovascular events (MACE, risk ratio [RR]: 1.76, 95% confidence interval [CI]: 1.39 to 2.22, P < .001; I²  = 49%), cardiac mortality (RR: 1.91, 95% CI: 1.18 to 3.09, P = .009; I²  = 0), all-cause mortality (RR: 2.14, 95% CI: 1.52 to 3.01, P < .001, I²  = 24%) and no reflow after pPCI (RR: 2.22, 95% CI: 1.70 to 2.90, P < .001, I²  = 59%). Moreover, higher preprocedural PLR was associated with increased risk of MACE (RR: 1.60, 95% CI: 1.25 to 2.03, I²  = 57%, P < .001) and all-cause mortality (RR: 2.36, 95% CI: 1.53 to 3.66, I²  = 78%, P < .001) during long-term follow-up of up to 82 months after discharge.

Higher PLR predicts poor in-hospital and long-term prognosis in STEMI patients after pPCI.