Effect of Any Form of Steroids in Comparison With That of Other Medications on the Duration of Olfactory Dysfunction in Patients With Covid-19

Phyo Zin Winn, Thein Hlaing, Kyaw Myo Tun, Seim Lei Lei


The life quality of about two-thirds of patients with COVID-19 is affected by related olfactory dysfunctions. The negative impact of olfactory dysfunction ranged from the decreased pleasure of eating to impaired quality of life. This research aimed to provide a comprehensive understanding of the effects of corticosteroid treatments by comparing that to other currently available treatments and interventions.


World Health Organization (WHO) declared the coronavirus outbreak a global health emergency on 30 January 2020. In the year 2022, the pandemic still exists, and the coronavirus mutates frequently from one variant to another prolonging the length of a global health emergency. The current coronavirus (COVID-19) can cause severe pneumonia in susceptible persons, and lead to the death of patients. Therefore, it is called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which causes multi-organ inflammation in its most severe form [1–3]. The SARS-CoV-2 virus enters the respiratory tract of humans through the angiotensin-converting enzyme 2 (ACE-2) receptors playing a crucial role in multiorgan dysfunction. Among manifestations of multiple organ dysfunction syndromes (MODS) caused by COVID-19, the loss of taste or smell is very common and the earliest warning sign resulting from sensory system dysfunction. During the COVID-19 pandemic, many people infected with the COVID-19 virus became defected their olfactory functions and lost their important quality of life [4].

Materials and method

According to the PICOT criteria (Table 1), the predefined research question was: "How the corticosteroid treatment options are more effective in reducing the duration of COVID-19-related olfactory dysfunction as compared with other types of interventions?". This review was conducted according to the 27-point checklist of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist [35]


In the identification stage, the principal reviewer identified 1568 (PubMed), 1329 (PubMed Central) and 1401 (EMBASE) titles and abstracts while the second reviewer identified 1449 (PubMed), 1120 (PubMed Central) and 1501 (EMBASE) titles and abstracts. Additionally, the principal and second reviewers identified 198 titles and abstracts, and 201 titles and abstracts were identified respectively through the continuous identifications of the citations and references. Accordingly, a total of 8767 records could be identified initially. Here, 7056 records were determined by Endnote software as duplications and therefore 1711 records were for the screening stage after removing the duplicated records. In the screening stage, 1690 records were removed again due to many reasons for ineligibility for providing this review question’s destinations and objectives (S1 Fig). In the selection stage, only 21 (10 Randomized Control Trials + 11 Quasi-experimental Studies) [36–56] were eligible for this review’s inclusion and exclusion criteria and selected for further analysis.


This review specialized in the knowledge of the possible treatment options for olfactory disorders among patients with COVID-19. The main aim of this review was to make a comparison between the efficacy of corticosteroid treatment options that have emerged as the most commonly used treatment interventions among patients with COVID-19 olfactory loss across the globe, and the effectiveness of other medical or non-medical interventions. This review was different from the previous systematic reviews and meta-analyses in terms of the number of included studies and sample sizes, study population, the specific aetiology and direct effects of treatment strategies on the COVID-19 induced olfactory dysfunction.


The life quality of about two-thirds of the patients with COVID-19 is affected by the related olfactory dysfunctions. This systematic review came to identify possible treatments and interventions for the olfactory dysfunction that was defined as the consequence of the COVID-19 infection and to provide a better understanding of the effects of corticosteroid treatment options that are the most commonly applied intervention strategy among coronavirus disease 2019 patients by comparing the efficacies of other treatments and interventions that are currently available. This review could conclude that corticosteroid treatment is effective in reducing the duration of the COVID-19-related smell loss and olfactory training, the basic, essential and effective intervention, should be used as a combination therapy.


The author sincerely and humbly gives special thanks to the supervisor, co-reviewer, all lecturers from STIMU and the University of Bedfordshire for their professional and academic guidance in conducting this systematic review research during the proposal preparation and dissertation periods, and my aunt for her financial support aa well as my friend and my lovely girlfriend for their psychosocial support during the stressful days of the dissertation period.

Citation: Winn PZ, Hlaing T, Tun KM, Lei SL (2023) Effect of any form of steroids in comparison with that of other medications on the duration of olfactory dysfunction in patients with COVID-19: A systematic review of randomized trials and quasi-experimental studies. PLoS ONE 18(8): e0288285.

Editor: Dong Keon Yon, Kyung Hee University School of Medicine, REPUBLIC OF KOREA

Received: October 2, 2022; Accepted: June 25, 2023; Published: August 2, 2023

Copyright: © 2023 Winn et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data is within the paper and its Supporting Information files.

Funding: The authors received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist

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