Impacts of different treatment methods on patients with COVID-related olfactory dysfunction: a systematic review and
Wenli You1, Lixin Luo1, Ping Zhou1
1School of Nursing, Chengdu University of Traditional Chinese Medicine, Chengdu City, Sichuan Province, China.
Background:
Olfactory Dysfunction (OD) is a prevalent neurological sequela of Coronavirus Disease 2019 (COVID-19) and substantially impairs quality of life. Although multiple pharmaceutical and non-pharmaceutical interventions have been proposed, their relative efficacy remains controversial. This study aimed to compare the efficacy of existing interventions for post-COVID-19 OD.
Methods:
PubMed, Embase, the Cochrane Library, and Web of Science databases were systematically searched up to July 31, 2025. Randomized Controlled Trials (RCTs), cohort studies, and non-RCT studies evaluating interventions for post-COVID-19 OD were included. Study quality was assessed using the National Institutes of Health (NIH) scale and the Newcastle-Ottawa Scale (NOS). Data were analyzed using RStudio and Stata. The interventions were ranked by Surface Under the Cumulative Ranking (SUCRA) values.
Results:
A total of 44 studies involving 3,516 patients and 26 interventions were included, with overall moderate to high quality. Chelators (Standardized Mean Difference [SMD = 3.61], 95% Credible Interval [CrI]: 2.77, 4.55) significantly improved total olfactory scores and their subdomains (with SUCRA values of 98.2%). Platelet-rich plasma (SMD = 1.33, 95% CrI: 0.92, 1.74) markedly improved the results of the University of Pennsylvania Smell Identification Test (UPSIT). Corticosteroids substantially improved olfactory function, as revealed by the Visual Analogue Scale (VAS) (SMD = 1.99, 95% CrI: 0.52, 3.48). Functional Septorhinoplasty (FSPR) demonstrated superior improvement in sinonasal-related quality of life, as measured by the 22-item Sino-nasal Outcome Test (SNOT-22) (SMD = -1.06, 95% CrI: -1.91, -0.21).
Conclusion:
Chelators and chelators combined with other interventions demonstrated benefit in improving post-COVID-19 olfactory function, offering new directions for multi-target therapies. Further high-quality RCTs are required to confirm these findings.
