ARE ROUTINE HAEMATOLOGICAL PARAMETERS- MEAN PLATELET VOLUME (MPV), NEUTROPHIL-TO-LYMPHOCYTE RATIO (NLR), AND WHITE BLOOD CELL COUNT (WBC) RELIABLE BIOMARKERS FOR RECURRENT APHTHOUS STOMATITIS (RAS)? - A SYSTEMATIC REVIEW AND META- ANALYSIS

Abstract

Background: Recurrent Aphthous Stomatitis (RAS) is a common, painful inflammatory disorder of the oral mucosa with a multifactorial etiology. Routine haematological parameters such as Mean Platelet Volume (MPV), Neutrophil-to Lymphocyte Ratio (NLR), and White Blood Cell Count (WBC) have been proposed as potential biomarkers reflecting systemic inflammation in RAS. However, individual studies report inconsistent findings. Objective: Cumulative assessment of the haematological parameters like mean platelet volume (MPV), neutrophil-to lymphocyte ratio (NLR), and total white blood cell count (WBC) across studies in recurrent aphthous stomatitis (RAS). Methods: A systematic literature search was conducted in PubMed, Cochrane Central, and Google Scholar up to 16 September 2025. Case-control and cross-sectional studies reporting MPV, NLR, and/or WBC in RAS patients versus controls were included. Study quality was assessed using the AXIS tool. Random-effects meta-analysis was performed using Review Manager 5.4, with outcomes reported as standardized mean differences (SMD) and 95% confidence intervals (CI). A p-value of <0.05 was considered statistically significant for the overall pooled effect. Results: Six studies (total n=828 participants) met the inclusion criteria. Meta-analysis showed a non-significant trend towards higher MPV in RAS (SMD = 1.09; 95% CI: -0.04 to 2.22; p=0.06) with extreme heterogeneity (I² = 98%). NLR was significantly elevated in RAS patients (SMD = 0.39; 95% CI: 0.04 to 0.75; p=0.03), though heterogeneity was substantial (I² = 79%). No significant difference was found in WBC count (SMD = 0.23; 95% CI: -0.45 to 0.90; p=0.51; I² = 94%). Conclusion: NLR appears to be a promising inflammatory marker linked to RAS, hinting at low-grade, ongoing inflammation. Right now, there’s just not enough solid evidence to say that MPV or WBC are useful biomarkers due to the inconsistent results. Well-designed studies will be required to establish the clinical importance of these biomarkers.