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Table of Contents
ORIGINAL ARTICLE
Year : 2022  |  Volume : 24  |  Issue : 3  |  Page : 143-146

The prevalence, duration, and outcome of anosmia in COVID-19 subjects admitted to two tertiary care hospitals in Saudi Arabia


1 Department of Otolaryngology-Head and Neck Surgery, King Faisal Specialist Hospital and Research Centre, Jeddah, Saudi Arabia
2 Department of Otolaryngology-Head and Neck Surgery, King Faisal Specialist Hospital and Research Centre, Jeddah; Department of ORL-HNS, Collage of Medicine, Umm Al-Qura University, Mecca, Saudi Arabia
3 Department of Otolaryngology-Head and Neck Surgery, King Faisal Specialist Hospital and Research Centre; Department of ORL-HNS, Collage of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
4 Department of ORL-HNS, Collage of Medicine, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
5 Department of ORL-HNS, Collage of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
6 Department of Pediatrics, King Abdulaziz Medical City, National Guard Health Affairs, Jeddah, Saudi Arabia
7 Department of ORL-HNS, Ohud Hospital, Medina, Saudi Arabia

Date of Submission18-Aug-2022
Date of Decision09-Sep-2022
Date of Acceptance10-Sep-2022
Date of Web Publication30-Sep-2022

Correspondence Address:
Dr. Samiha F Khayyat
King Abdulaziz Medical City, National Guard Health Affairs, Jeddah
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/sjoh.sjoh_37_22

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  Abstract 


Objectives: The objective is to investigate anosmia in patients with COVID-19 in tertiary care hospitals in two major cities in the Kingdom of Saudi Arabia to determine its prevalence, clinical characteristics, duration, and outcome. Methods: A retrospective study on COVID-19 patients who are admitted to our tertiary care hospital between May and December 2020. The inclusion criteria were all patients who are admitted to our tertiary care hospital with a confirmed diagnosis of COVID-19 in this study, we enrolled 545 patients for this study. Results: Of the 545 contacted subjects, 277 (50.82%) answered, whereas 268 were excluded, 26 (4.8%) of which passed away. One hundred and nineteen (42.96%) subjects were female whereas 158 (57.04%) were male. The mean age was 42.81 ± 16.76 standard deviation. About 162 (58.47%) of the 277 who completed the interview had anosmia; moreover, anosmia was grouped into transient and persistent anosmia. It was persistent in 15 subjects (5.4%) and transient in 147 subjects (94.6%); the range duration of transient anosmia was 1–180 days with a median of 10 (6, 20) days (median and interquartile range). Of the 277 subjects, 148 (53.4%) had ageusia; 15 subjects (5.4%) experienced anosmia as the only symptom, and 12 subjects (4.33%) developed ageusia as the only symptom. Of all the symptomatic subjects with anosmia 162 (58.5%), and 76 (41.36%) subjects reported a subjective impact on quality of life. Conclusion: More than half of the COVID-19 patients in the study presented with anosmia that was transient in the majority of cases.

Keywords: Anosmia, COVID-19, olfactory disorder


How to cite this article:
Sheffah FR, Marglani OA, Alherabi AZ, Heaphy JC, Al-Tammas AH, Al-Khatib TA, Marghalani YO, Ghazzawi RA, Tashkandi AY, Khayyat SF, Albeladi MA. The prevalence, duration, and outcome of anosmia in COVID-19 subjects admitted to two tertiary care hospitals in Saudi Arabia. Saudi J Otorhinolaryngol Head Neck Surg 2022;24:143-6

How to cite this URL:
Sheffah FR, Marglani OA, Alherabi AZ, Heaphy JC, Al-Tammas AH, Al-Khatib TA, Marghalani YO, Ghazzawi RA, Tashkandi AY, Khayyat SF, Albeladi MA. The prevalence, duration, and outcome of anosmia in COVID-19 subjects admitted to two tertiary care hospitals in Saudi Arabia. Saudi J Otorhinolaryngol Head Neck Surg [serial online] 2022 [cited 2022 Nov 28];24:143-6. Available from: https://www.sjohns.org/text.asp?2022/24/3/143/357638




  Introduction Top


The World Health Organization (WHO) officially classified COVID-19 as a public health emergency of international concern on January 30, 2020, and as a global pandemic on March 11, 2020.[1] Patients infected with this virus have presented with a variety of symptoms or with single symptoms of differing severities. According to a focused review conducted by Cevik et al., the most reported symptoms have been fever, cough, fatigue, and myalgia. In addition, gastrointestinal symptoms such as anorexia, nausea, vomiting, and diarrhea, olfactory disorders (hyposmia or anosmia), and neurological manifestations (such as headache, dizziness, and altered consciousness) have also been reported. Most symptoms appear 2–14 days after exposure to the virus.[2]

A systematic review of symptoms in 10,818 patients conducted in primary care centers and university hospitals in China, France, Iran, Italy, and the United States revealed that 8088 (74.8%) patients had anosmia.[3] However, a systematic review and meta-analysis of 19,424 COVID-19 patients in 27 published articles put the estimated global pooled prevalence of loss of smell at 48.47%; moreover, Sudre et al. concluded that anosmia-ageusia was the most consistent and strongest associated symptom with a positive COVID-19 test after pooling 514,459 tests from over 10 million respondents.[4],[5] Some research has found that anosmia was the sole symptom of COVID-19.[6],[7] A retrospective study by Lechien et al. concluded that patients who experienced anosmia did so within 4.4 days of the onset of illness and recovered within 8.96 days on average.[7] The objective of the present study was to determine the prevalence and clinical characteristics, such as duration and outcome, of anosmia in subjects with COVID-19 in tertiary care hospitals in two major cities in the Kingdom of Saudi Arabia.


  Methods Top


This research was a cross-sectional study of COVID-19 subjects admitted to tertiary care governmental hospitals, King Faisal Specialist Hospital and Research Centre–Riyadh and King Faisal Specialist Hospital and Research Centre–Jeddah, located in the central and western regions of Saudi Arabia, respectively. The inclusion criteria included subjects aged 8 years or more, being admitted to the hospital and having a nasopharyngeal swab-confirmed diagnosis of COVID-19. Subjects with communication challenges were excluded, such as leaving the wrong phone number, inability to speak clearly, speaking a language other than Arabic or English, unresponsiveness, passing away, and inaccessibility. This study was conducted after obtaining ethical approval with IRB number 2020-92 from the Ethical Committee of King Faisal Specialist Hospital and Research Centre-Jeddah to access subjects' electronic medical records stored in the Research Electronic Data Capture database. Subjects were assigned study codes to ensure confidentiality. We investigated subjects who met our eligibility criteria and agreed to participate after explaining the interview and obtaining informed consent.

The investigators collected data from telephone interviews with each subject between December 2020 and January 2021 using a prepared questionnaire developed specifically for this study in both Arabic and English [Figure 1]. The subjects were asked to confirm the demographic variables: age, in years, and gender, male or female. Then, they were asked about the clinical variables: whether the subjects experienced anosmia or ageusia, information about the character (either anosmia or ageusia), if either was the only symptom, if either was transient or persistent and duration of either, in days. Moreover, investigators inquired whether the symptom or symptoms generally had a negative impact on their quality of life with a yes or no question.
Figure 1: Anosmia questionnaire

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Data collected from the databases and subjects were entered into a statistical software program Statistical Package for the Social Sciences (SPSS) Version 21, Provided by International Business Machines (IBM) Armonk, New York, United States. Mean and standard deviation (SD) were used to describe the normally distributed numerical variables such as age. Median and interquartile range was used for the duration of symptoms as it was not normally distributed. Percentages were used to describe categorical variables such as gender, whether the subjects had anosmia or not, if anosmia was the only symptom, if the subjects developed ageusia, if anosmia or ageusia persisted, and whether anosmia had an impact on their quality of life.


  Results Top


Of the 545 contacted subjects, 277 (50.82%) answered and agreed to participate, whereas 268 were excluded, 26 (4.8%) of which passed away. One hundred and nineteen (42.96%) of the subjects who answered were female, and 158 (57.04%) were male. The mean age was 42.81 ± 16.76 SD. Subjects were asked the questions above. About 162 (58.47%) of the 277 who completed the interview had anosmia; moreover, anosmia was grouped into transient and persistent anosmia, see [Figure 2]. Anosmia was persistent in 15 subjects (5.4%) and transient in 147 subjects (94.6%); the range of duration of transient anosmia was 1–180 days with a median of 10 (6, 20) days (median ± interquartile range). Of the 277 subjects, 148 (53.4%) had ageusia; 15 subjects (5.4%) experienced anosmia as the only symptom, and 12 subjects (4.33%) developed ageusia as the only symptom. Of all the symptomatic subjects with anosmia 162 (58.5%), 76 (41.36%) subjects reported a subjective impact on quality of life. A summary of the results is summarized in [Table 1].
Figure 2: Prevalence of Anosmia in COVID-19 patients

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Table 1: Summary of the descriptive data of the investigated patients

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  Discussion Top


Since the outbreak of COVID-19, numerous studies worldwide have investigated various aspects of this disease. The loss of smell, whether hyposmia or anosmia, has been added to the WHO symptomatology of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) criteria and has helped with the early diagnosis and prognosis of the disease.[3] Studies of the pathophysiology of olfactory dysfunction (OD) in COVID-19 patients indicate temporary loss of function of supporting cells in the olfactory epithelium that indirectly causes changes to olfactory sensory neurons and that anosmia preceded COVID-19 diagnosis in 73% of cases studied and that the presence of anosmia showed a milder course of COVID-19 infection.[8],[9]

Some studies have shown an interesting geographical distribution of this symptom, but there have not been many in the Middle East or Gulf region. A systematic review by Pier Carmine Passarelli et al. included five studies conducted in primary care centers and university hospitals in China, France, Iran Italy, and the United States of 10,818 COVID patients, 8088 of whom had anosmia (74.8%, range 5.6%–83.4%). In China, of the 214 patients included in the study, 11 experienced anosmia (5.6%), while in Italy, the study included 59 patients, six of whom (6%) had anosmia. In contrast, in the United States, of the 59 patients reviewed, 42 (71%) had anosmia and in France, 367 (88%) of the 417 COVID patients reviewed had anosmia. However, the highest prevalence of anosmia among COVID-19 patients was recorded in Iran at 83.4% (8396 of 10,069 patients reviewed).[3]

A systematic review and meta-analysis of 27 published articles (6 from Asia, 17 from Europe, and 4 from North America) estimated the global pooled prevalence of loss of smell among 19,424 COVID-19 patients at 48.47% (95% confidence interval [CI], 33.78%–63.29%). By region, the estimated prevalence was Asia 54.52% (95% CI, 39.32%–69.32%), Europe 40.98% (95% CI, 20.71%–62.91%), and North America 33.19% (95% CI, 8.50%–64.25%).[4]

A significant difference in the prevalence of anosmia in COVID-19 patients has been observed between self-reported cases (subjective) and those diagnosed with odor threshold tests (objective). A study published by Hannum et al. found that studies using objective methods reported around 77% prevalence overall while those relying on self-reporting were around 44%.[10]

A systematic review and meta-analysis conducted by Agyman et al. included 24 studies on 8438 confirmed COVID-19 cases in 13 countries. The proportion of patients presenting with OD was 41% (95% CI, 28.5%–53.9%). Numerous other factors were studied in association with anosmia such as age, type of anosmia assessment, and gender. Increasing age was associated with lower prevalence rates of anosmia, and objective assessments of OD revealed higher prevalence rates than self-reporting. No significant difference was reported between males and females in the prevalence of anosmia in COVID-19 patients.[11]

In the Middle East, a study published by Al-Ani and Acharya of patients with COVID-19 at a primary health center in Doha, Qatar, reported that seven of 141 experienced anosmia (4.96%).[12]

In Saudi Arabia, the only study published thus far was conducted in Taif on hospital patients from May to July 2020 and reported OD in 53% of 1022 COVID-19 patients, of which 32.7% were anosmic and 20.3% were hyposmic.[13]

A few studies have addressed the duration of anosmia in COVID-19 patients. Firouzeh Heidari et al. reported that fever, myalgia, and fatigue improved in the first few days but that anosmia remained.[6]

Another study concluded that out of 247 patients with clinically resolved infections, OD persisted after the resolution of other symptoms in 63% of cases. The short-term olfaction recovery rate assessed in 59 clinically cured patients was 44%. In all, 72.6% of these patients recovered olfactory function within the first 8 days following the resolution of the disease. On average, patients experienced anosmia within 4.4 days of disease onset and recovered within 8.96 days.[7]

A different study showed that all patients had fully recovered from anosmia and ageusia in 3–12 days with a mean of 6.89 days ± 3.056,[9] while a retrospective study conducted by Mubaraki et al. in Taif found the mean duration of OD was 10.8 ± 9.7 days; the mean duration of anosmia was 12.1 ± 10.3 days, and that of hyposmia was 8.7 ± 8.3 days.[13]

A review of contemporary evidence undertaken to determine if dysgeusia and anosmia are reliable forerunner symptoms for COVID-19 infection in patients presenting with acute-onset loss of taste or smell found that data from Europe, Iran, and the United States indicate anosmia and dysgeusia appeared before general COVID-19 symptoms in 64.5% and 54% of patients, respectively, and concluded that the topic needs further study.[14] However, a later study by Sudre et al. with 514,459 tests from over 10 million respondents pointed out that anosmia-ageusia was the finding most consistent with a positive COVID-19 test (robust aggregated rank one, meta-analyzed random effects odds ratio [OR] 16.96, 95% CI 13.13–21.92), while fever, shortness of breath, and cough were given ranks two (OR 6.45,4.25–9.81), three (OR 4.69, 3.14–7.01), and four (OR 4.29,3.13–5.88), respectively.[5] In addition, after recruiting 417 COVID-19 patients, Lechien et al. found out that 88% of patients reported taste dysfunction, and 85.6% experienced smell dysfunction, both of which had a significant association between both symptoms (P < 0.001).[7]

To elaborate on why taste dysfunction occurs, one theory is that SARS-CoV-2 binds to angiotensin-converting enzyme-2 receptors in the salivary glands which may weaken salivary flow, leading to “conductive” gustatory dysfunction.[15] Inflammation, abnormal cell turnover, and reduced taste bud sensitivity may be triggered by the binding of the virus to oral mucosal cells which may lead to sensorineural gustatory dysfunction.[15]

Limitations of this study

Our study is the first to be conducted in tertiary care hospitals, which might indicate a sicker patient population or the presence of comorbidities. The other studies were conducted in university hospitals, three primary care centers,[3],[12] or complex hospitals.[8],[13] It would be interesting to compare our results with those for the general population in the same region. This study also relied on self-reporting through telephone interviews and not on objective odor threshold tests.


  Conclusion Top


More than half of our COVID-19 patients experienced anosmia during their infections. Therefore, we consider anosmia a significant symptom of COVID-19 infection. Further studies in our region on a larger scale and more focused on comorbidities will be needed to determine the prevalence of anosmia for prospective management of this manifestation and to further assess persistent anosmia.

Acknowledgment

The authors would like to thank the Deanship of Scientific Research at Umm Al-Qura University for supporting this work by Grant Code: (20UQU0025DSR).

Data from this research were provided by COVID-19 Clinical and Epidemiological Database resource at the King Faisal Specialist Hospital and Research Center.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Hiscott J, Alexandridi M, Muscolini M, Tassone E, Palermo E, Soultsioti M, et al. The global impact of the coronavirus pandemic. Cytokine Growth Factor Rev 2020;53:1-9.  Back to cited text no. 1
    
2.
Cevik M, Bamford CG, Ho A. COVID-19 pandemic-a focused review for clinicians. Clin Microbiol Infect 2020;26:842-7.  Back to cited text no. 2
    
3.
Passarelli PC, Lopez MA, Mastandrea Bonaviri GN, Garcia-Godoy F, D'Addona A. Taste and smell as chemosensory dysfunctions in COVID-19 infection. Am J Dent 2020;33:135-7.  Back to cited text no. 3
    
4.
Ibekwe TS, Fasunla AJ, Orimadegun AE. Systematic review and meta-analysis of smell and taste disorders in COVID-19. OTO Open 2020;4:2473974X20957975.  Back to cited text no. 4
    
5.
Sudre CH, Keshet A, Graham MS, Joshi AD, Shilo S, Rossman H, et al. Anosmia, ageusia, and other COVID-19-like symptoms in association with a positive SARS-CoV-2 test, across six national digital surveillance platforms: An observational study. Lancet Digit Health 2021;3:e577-86.  Back to cited text no. 5
    
6.
Heidari F, Karimi E, Firouzifar M, Khamushian P, Ansari R, Mohammadi Ardehali M, et al. Anosmia as a prominent symptom of COVID-19 infection. Rhinology 2020;58:302-3.  Back to cited text no. 6
    
7.
Lechien JR, Chiesa-Estomba CM, De Siati DR, Horoi M, Le Bon SD, Rodriguez A, et al. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): A multicenter European study. Eur Arch Otorhinolaryngol 2020;277:2251-61.  Back to cited text no. 7
    
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Vaira LA, Salzano G, Deiana G, De Riu G. Anosmia and ageusia: Common findings in COVID-19 patients. Laryngoscope 2020;130:1787.  Back to cited text no. 8
    
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Borsetto D, Hopkins C, Philips V, Obholzer R, Tirelli G, Polesel J, et al. Self-reported alteration of sense of smell or taste in patients with COVID-19: A systematic review and meta-analysis on 3563 patients. Rhinology 2020;58:430-6.  Back to cited text no. 9
    
10.
Hannum ME, Ramirez VA, Lipson SJ, Herriman RD, Toskala AK, Lin C, et al. Objective sensory testing methods reveal a higher prevalence of olfactory loss in COVID-19-positive patients compared to subjective methods: A systematic review and meta-analysis. Chem Senses 2020;45:865-74.  Back to cited text no. 10
    
11.
Agyeman AA, Chin KL, Landersdorfer CB, Liew D, Ofori-Asenso R. Smell and taste dysfunction in patients with COVID-19: A systematic review and meta-analysis. Mayo Clin Proc 2020;95:1621-31.  Back to cited text no. 11
    
12.
Al-Ani RM, Acharya D. Prevalence of Anosmia and Ageusia in Patients with COVID-19 at a Primary Health Center, Doha, Qatar. Indian J Otolaryngol Head Neck Surg. 2020 Aug 19:1-7. doi: 10.1007/s12070-020-02064-9. Epub ahead of print  Back to cited text no. 12
    
13.
Mubaraki AA, Alrbaiai GT, Sibyani AK, Alhulayfi RM, Alzaidi RS, Almalki HS. Prevalence of anosmia among COVID-19 patients in Taif City, Kingdom of Saudi Arabia. Saudi Med J 2021;42:38-43.  Back to cited text no. 13
    
14.
Samaranayake LP, Fakhruddin KS, Panduwawala C. Sudden onset, acute loss of taste and smell in coronavirus disease 2019 (COVID-19): A systematic review. Acta Odontol Scand 2020;78:467-73.  Back to cited text no. 14
    
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Xu H, Zhong L, Deng J, Peng J, Dan H, Zeng X, et al. High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa. Int J Oral Sci 2020;12:8.  Back to cited text no. 15
    


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