Therapeutic effect of anti-neuroinflammatory supplement combined with olfactory training on post-covid olfactory...

There is no established specific treatment for post-COVID olfactory dysfunction (PCOD) currently. Olfactory training (OT) is the only effective intervention supported by clinical evidence. The anti-neuroinflammatory supplement palmitoylethanolamide and luteolin (PEA-LUT) has shown potential in alleviating the symptoms of post-COVID, but its therapeutic effect on olfactory dysfunction and the gain effect when combined with OT remain to be evaluated.

We comprehensively searched the online databases EMBASE, PubMed, ScienceDirect, Web of Science, Cochrane Library, Google Scholar, and ClinicalTrials.govfor the literature related to the treatment of PCOD, identified studies reporting the efficacy of PEA-LUT combined with OT, extracted the treatment outcome data, and performed data synthesis.

A total of 7 eligible RCTs published between 2021 and 2024 were included, comprising 525 patients with PCOD. Of the seven studies, five (71.4%) used the full Threshold-Discrimination-Identification (TDI) scoresystem to assess olfactory function, while two (28.6%) used only the Identification ("I") subscale; 332 patients (63.2%) received PEA-LUT + OT therapy and 203 (38.8%) received OT alone. Meta-analysis of these studies showed that patients receiving PEA-LUT combined with OT had significantly higher TDI scores compared to those receiving OT alone (Standard mean difference (SMD) = 0.90; 95% CI: 0.24-1.58; P < 0.01). The overall response rate was also significantly higher in the combination group (Risk difference (RD) = 0.33; 95% CI: 0.01-0.64; P = 0.04).

The neuroprotective properties of PEA-LUT appear to enhance recovery from post-COVID olfactory dysfunction. When combined with olfactory training, this treatment shows promising potential as a novel therapeutic approach.