Prevalence of Olfactory Dysfunction in Coronavirus Disease 2019 (COVID‐19): A Meta‐analysis of 27,492 Patients

Abstract

Objectives/Hypothesis Olfactory dysfunction has been observed as one of the clinical manifestations in COVID‐19 patients. We aimed to conduct a systematic review and meta‐analysis to estimate the overall pooled prevalence of olfactory dysfunction in COVID‐19 patients. Study Design Systematic review and meta‐analyses. Methods PubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between 1 December 2019 and 23 July 2020. We used random‐effects model to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I 2 statistic and Cochran's Q test. Robustness of the pooled estimates was checked by different subgroup and sensitivity analyses This study is registered with PROSPERO (CRD42020183768). Results We identified 1162 studies, of which 83 studies (n = 27492, 61.4% female) were included in the meta‐analysis. Overall, the pooled prevalence of olfactory dysfunction in COVID‐19 patients was 47.85% [95% CI: 41.20–54.50]. We observed olfactory dysfunction in 54.40% European, 51.11% North American, 31.39% Asian, and 10.71% Australian COVID‐19 patients. Anosmia, hyposmia, and dysosmia were observed in 35.39%, 36.15%, and 2.53% of the patients, respectively. There were discrepancies in the results of studies with objective (higher prevalence) versus subjective (lower prevalence) evaluations. The discrepancy might be due to false‐negative reporting observed in self‐reported health measures. Conclusions The prevalence of olfactory dysfunction in COVID‐19 patients was found to be 47.85% based on high‐quality evidence. Due to the subjective measures of most studies pooled in the analysis, further studies with objective measures are advocated to confirm the finding. Level of Evidence 2 Laryngoscope , 2020

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“…Olfactory dysfunction, which has become one of the sought-after clinical features of COVID-19, has been associated with less severe disease manifestation. 1 Yet, the previously deemed 'fortunate' patients with olfactory dysfunction who successfully recovered from COVID-19 are now being afflicted by another sinister condition known as parosmia, which is found to be more debilitating than loss of smell.…”

Coronavirus Disease 19 from the Perspective of Ageing with Focus on Nutritional Status and Nutrition Management—A Narrative Review

“…With regard to individual studies, the prevalence range is widely related to differences in age, severity of disease, setting, different assessment methods, and study design [ 55 , 56 ]. Higher prevalence has been reported in studies with objective assessment methods compared with subjective methods, as patients might be unaware of their dysfunction leading to a possible underestimation of the problem [ 57 , 58 ].…”

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“…Najobszerniejsza metaanaliza Saniasiai i wsp. [14], która objęła 83 opublikowane badania z danymi 27 492 pacjentów, wykazała, iż zaburzenia węchu dotyczą 47,85% chorych w przebiegu zakażenia SARS--CoV-2, przy czym anosmia rozwija się u 35,39%, hyposmia -u 36,15%, a dysosmia -u 2,53%. Natomiast przegląd systematyczny 40 badań (10 228 chorych) -przeprowadzony przez zespół Amorim Dos Santos i wsp.…”