The Association Between Platelet Indices and Osteoarthritis: A Systematic Review and Meta-analysis.

BACKGROUND: The role of routinely available platelet biomarkers - platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit (PCT) - is poorly understood in osteoarthritis (OA). This systematic review and meta-analysis aimed to assess the association between platelet biomarkers and the occurrence and severity of OA. METHODS: MEDLINE, Embase and the Cochrane libraries were searched from inception to June 2025. We included studies reporting on the association between PLT, MPV, PDW and PCT with the presence and severity of OA. We tabulated mean differences (MDs) of platelet biomarkers between patients with OA against healthy controls, as well as between patients with severe OA and mild/moderate OA to generate pooled effect measures using random-effects inverse variance modelling. RESULTS: Fourteen studies, with a total of 13 843 patients, were included in this systematic review. Mean platelet volume (fL) was significantly reduced in OA as compared to healthy controls, MD = -0.52 (95% CI: -0.65 to -0.39, P < .01). Platelet count was not significantly different between the groups, MD = 2.32 (95% CI: -6.29 to 10.94, P = .60). Both PLT and MPV were not significantly different between the 2 groups, with pooled mean differences of 3.57 (95% CI = -8.21 to 15.35, P = .55) and 0.37 (95% CI = -0.33 to 1.08, P = .30), respectively. CONCLUSIONS: This meta-analysis found MPV to be significantly reduced in OA. Further studies are needed to further evaluate the prognostic significance of mean platelet volume in OA.