Efficacy of topical steroids for the treatment of olfactory disorders caused by COVID‐19: A systematic review and meta‐analysis

Abstract

Objectives The aim of this study was to assess the effect of topical steroids on acute‐onset olfactory dysfunction in patients infected with COVID‐19. Design and Setting Systematic review and meta‐analysis of cohort studies. Participants Patients infected with COVID‐19. Main outcome measures PubMed, Embase, the Web of Science, SCOPUS, Cochrane database and Google Scholar were searched for articles up to September 2021. We analysed studies comparing the improvement of olfactory dysfunction between topical steroid treatment and control groups (placebo or no treatment). In addition, we performed a subgroup analysis by study type. Results The improvement of olfactory score at 2 (standardised mean difference [SMD] = 0.7272, 95% confidence interval = [0.3851, 1.0692], p < .0001, I 2 = 62.1%) and 4 weeks post‐treatment (SMD = 1.0440 [0.6777, 1.4102], p < .0001, I 2 = 61.2%) was statistically greater in the treatment than control group. However, there was no significant difference (odds ratio [OR] = 1.4345 [0.9525, 2.1604], p = .0842, I 2 = 45.4%) in the incidence of fully recovery from anosmia/hyposmia between the treatment and control groups. In subgroup analysis, there were no significant differences in the improvement of olfactory score at 4 weeks post‐treatment (OR = 0.6177 [0.1309, 1.1045] vs. 0.1720 [0.8002, 1.5438], p = .0761) or the incidence of full recovery from anosmia/hyposmia (OR = 1.8478 [0.6092, 5.6053] vs. 1.3784 [0.8872, 2.1414], p = .8038) between randomised and non‐randomised controlled trials. Conclusions Although this meta‐analysis found that topical steroids improved the acute‐onset olfactory dysfunction caused by COVID‐19, there was no difference in the rate of full olfactory recovery between treated and control patients.

In reference to Intranasal Corticosteroid Treatment on Recovery of Long‐Term Olfactory Dysfunction Due to COVID‐19

“… 13 Some preliminary studies reported promising data in the treatment of persistent OD 14 that have not been supported by larger trials 15 , 16 , 17 and meta‐analysis. 18 This is consistent with studies inpost‐viral olfactory loss (PVOL) prior to COVID‐19, 19 , 20 probably due to a failure of delivery to the OE. 21 …”

Therapies for COVID-19-Related Persistent Olfactory Disorders: One of the Good Fruits of the Pandemic

“…Kasiri et al [ 26 ] and Hintschich et al [ 27 ] treated patients with persistent ODs after SARS-CoV-2 infection with mometasone furoate as in our study without detecting significant benefits. This was confirmed by the recent meta-analysis of Kim et al [ 30 ] and is likely related to poor delivery of the corticosteroid spray to the olfactory epithelium [ 31 , 32 ]. Similarly, oral corticosteroids also did not demonstrate a clear advantage in terms of olfactory recovery compared to olfactory training alone [ 28 ].…”

Topical Administration of Mometasone Is Not Helpful in Post-COVID-19 Olfactory Dysfunction

“…However, the therapy duration was shorter, and olfaction was not assessed psychophysically but only by patients’ subjective self-assessment. Additionally, a recent meta-analysis identified no statistically significant difference in the olfactory recovery between patients receiving topical corticosteroids and controls [ 27 ].…”