Short-term efficacy of platelet-rich plasma in the treatment of persistent olfactory dysfunction: systematic review and meta-analysis

Purpose To assess the short-term effects of topical platelet-rich plasma (PRP) injection on persistent refractory olfactory dysfunction. Methods A comprehensive literature search of the PubMed, SCOPUS, EMBASE, Web of Science, Google Scholar, and Cochrane databases was conducted for articles up to November 2023. The search focused on studies that compared the amelioration of olfactory dysfunction between a topical PRP treatment cohort and a control group (receiving either placebo or no treatment), along with pre- and post-treatment comparisons. Subgroup analysis of the evaluation of olfactory function was also performed. Results The improvement in olfactory scores 1-3 months post-treatment (standardized mean difference = 1.5354 [95% confidence interval: 0.7992; 2.2716], I2 = 83.8%) was greater in the treatment group than in the control group. In the treatment group, PRP increased the threshold, discrimination, and identification (TDI) score for Sniffin' Sticks by > 5.5 (minimum clinically significant difference; mean difference = 6.1789 [3.9788; 8.3789], I2 = 0.0%), indicating clinically significant improvement based on verified examinations. The rate of significant improvement among patients was 0.6683 [0.5833; 0.7436] after treatment. All TDI subdomains were significantly and similarly improved after treatment. Conclusion This meta-analysis suggests that injection of PRP into the olfactory fissure or surrounding mucosal areas is an effective treatment for persistent refractory olfactory dysfunction in the short term.