Platelet-to-lymphocyte ratio and mean platelet volume in recurrent aphthous stomatitis: Systematic review and meta-analysis of group differences

Objectives: Haematological parameters are frequently employed to predict the clinicalcourse and prognosis of Recurrent aphthous stomatitis (RAS). This systematic review andmeta-analysis synthesise evidence regarding whether platelet-to-lymphocyte ratio (PLR) andmean platelet volume (MPV) differ significantly between individuals with RAS and healthycontrols. Methods: Relevant publications were identified through searches of PubMed, Embase,Scopus, EBSCOhost, and Web of Science. Results are reported as standardised meandifferences (SMDs) with 95% confidence intervals (CIs). A random-effects model wasapplied to address significant heterogeneity affecting pooled effect size interpretation. Risk ofbias was assessed using the Newcastle-Ottawa Scale, and evidence quality was evaluatedwith the GRADE approach. Results: A total of seventeen articles reporting MPV and PLR data were included in themeta-analysis to assess differences between RAS patients and healthy controls. MPV washigher in RAS patients (SMD = 0.42; 95% CI: -0.53 to 1.36), although substantialheterogeneity was observed. Recomputed MPV was only marginally higher in RAS patients(SMD = 0.01; 95% CI: -0.31 to 0.32). The study population was the only significantmoderator of the pooled effect size. PLR values were also only slightly higher in RASpatients (SMD = 0.04; 95% CI: -0.06 to 0.14), with low to moderate heterogeneity. GRADEevidence quality was rated very low for computed MPV and low for PLR. A meta-analysisdemonstrates no significant difference in mean platelet volume or platelet-lymphocyte ratiobetween RAS patients and healthy controls, underscoring the imperative to identify othersystemic factors in RAS pathogenesis.