Prevalence Of Olfactory Dysfunction Research Articles

Assessment of olfactory and gustatory functions in COVID-19 patients

BackgroundOlfactory and gustatory disorders are common problems encountered during the COVID-19 pandemic with a significant impact on the patient’s quality of life: The aim of this study was to assess the olfactory and gustatory functions in COVID-19 patients with correlation between them and clinical and laboratory markers. This was a cross-sectional study conducted on 63 subjects recruited from the COVID-19 clinics at Police Authority and Menoufia University hospitals. The patients were assessed using history taking, anterior rhinoscopy, endoscopic examination, computed tomography, and polymerase chain reaction (PCR) test. Olfactory functions were assessed using the alcohol threshold test. Gustatory functions were assessed using the three-drop method. The olfactory and gustatory functions were correlated with age, gender, and laboratory parameters. Also, the recovery of smell and taste disorders was correlated with our assessed laboratory markers.ResultsThe prevalence of olfactory dysfunction among study participants was 41 patients (65%) of the participants including 12 patients (19.1%) having mild hyposmia, 10 patients (15.8%) having moderate hyposmia, 9 patients (14.3%) having severe hyposmia, and 10 patients (15.8%) having complete anosmia. The prevalence of gustatory dysfunction among study participants was 24 patients (38.1%). Age, gender, and laboratory parameters did not show any statistically significant difference between those who experienced olfactory dysfunction or gustatory dysfunction and those who did not. However, there was a significant positive correlation between the total leucocytic count, serum level of CRP, and serum level of D-dimer and the degree of olfactory dysfunction (0.049, 0.03, and 0.02, respectively). There was a nonsignificant correlation between recovery of olfactory and gustatory dysfunction and laboratory markers.ConclusionOlfactory and gustatory dysfunction are established clinical presentations among COVID-19-positive patients. The laboratory markers had no correlation with the incidence of these dysfunctions or their recovery. However, TLC, serum CRP, and serum D-dimer had a significant positive correlation with the severity of olfactory dysfunction.

Olfactory Dysfunction in Healthcare Workers with COVID-19: Prevalence and Associated Factors.

The COVID-19 pandemic is a real global health crisis. Its clinical presentation has evolved over time with an increasing number of symptoms. Olfactory dysfunction (OD) has recently been recognized as a frequent symptom relevant to screening for COVID-19, especially in pauci-asymptomatic forms. However, the underlying mechanisms of OD are not yet fully understood. To determine the prevalence of OD in healthcare workers with SARS-CoV-2 and to identify its associated factors. This is a cross-sectional, analytical study, carried out during a period of six months and including all healthcare workers at Farhat Hached Academic Hospital (Tunisia) who were diagnosed with SARS-CoV-2 by PCR, RAT, or chest CT scan. A total of 474 healthcare workers were included, representing a participation rate of 85.4%. The mean age was 41.02±10.67 years with a sex ratio of 0.2. The distribution of this population by department noted that it was mainly maternity (13.9%). The most presented workstation was nursing (31.4%). OD represented 39.2% of the reasons for consultation. Hospitalization was indicated in 16 patients (3.4%). The average duration of hospitalization was 8.87 ± 7.8 days. The average time off work was 17.04 ± 11.6 days. OD persisted for more than 90 days in 35 patients (7.4%). After multiple binary logistic regression, OD was statistically associated with female gender (p =0.001; OR 95% CI: 2.46 [1.4-4.2]) and blue-collar occupational category (p =0.002; OR IC95%:3.1 [1.5-6.5]). A significant association was also noted between OD and professional seniority and absence from work duration (p =0.019; OR 95% CI: 0.97 [0.95-0.99] and p =0.03; OR 95% CI: 0.97 [0.95-0.99]) respectively. OD is common in COVID-19 patients. The identification of its associated factors may contribute to enhancing the understanding of its mechanism and drive therapeutic options.

Olfactory function after mild traumatic brain injury in children-a longitudinal case control study.

The prevalence of posttraumatic olfactory dysfunction in children after mild traumatic brain injury ranges from 3 to 58%, with potential factors influencing this variation, including traumatic brain injury severity and assessment methods. This prospective longitudinal study examines the association between mild traumatic brain injury and olfactory dysfunction in children. Seventy-five pediatric patients with mild traumatic brain injury and an age-matched healthy control group were enrolled. Olfactory function was assessed using the Sniffin' Sticks battery, which focuses on olfactory threshold and odor identification. The study found that children with mild traumatic brain injury had impaired olfactory function compared with healthy controls, particularly in olfactory threshold scores. The prevalence of olfactory dysfunction in the patient group was 33% and persisted for 1yr. No significant association was found between traumatic brain injury symptoms (e.g. amnesia, loss of consciousness) and olfactory dysfunction. The study highlights the importance of assessing olfactory function in children after mild traumatic brain injury, given its potential impact on daily life. Although most olfactory dysfunction appears transient, long-term follow-up is essential to fully understand the recovery process. The findings add valuable insights to the limited literature on this topic and urge the inclusion of olfactory assessments in the management of pediatric mild traumatic brain injury.

The Prognostic Value of Olfactory Dysfunction in Patients with COVID-19: The COVIDORA Study.

Among all studies describing COVID-19 clinical features during the first wave of the pandemic, only a few retrospective studies have assessed the correlation between olfac-tory dysfunction (OD) and the evolution of disease severity. The main aim was to assess whether OD is a predictive factor of COVID-19 severity based on the patient's medical management (outpa-tient care, standard hospital admission, and ICU admission). A national, prospective, mul-ticenter cohort study was conducted in 20 public hospitals and a public center for COVID-19 screen-ing. During the first wave of the pandemic, from 6 April to 11 May 2020, all patients tested positive for COVID-19 confirmed by RT-PCR underwent two follow-up ENT consultations within 10 days of symptom onset. The main outcome measures were the evolution of medical management (out-patient care, standard hospital admission, and ICU admission) at diagnosis and along the clinical course of COVID-19 disease. Among 481 patients included, the prevalence of OD was 60.7%, and it affected mostly female patients (74.3%) under 65 years old (92.5%), with fewer comor-bidities than patients with normal olfactory function. Here, 99.3% (290/292) of patients with OD presented with non-severe COVID-19 disease. Patients reporting OD were significantly less hospi-talized than the ones managed as outpatients, in either a standard medical unit or an ICU. Conclu-sions: As regards the clinical course of COVID-19 disease, OD could predict a decreased risk of hospitalization during the first wave of the pandemic.

Association between peripheral eosinophilia, JESREC score, and olfactory dysfunction in patients with chronic rhinosinusitis.

The purpose was to evaluate the relationship between peripheral eosinophilia, Japan Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) score, and olfactory dysfunction in chronic rhinosinusitis (CRS) patients and to explore the accuracy and specific cut points of the JESREC score in predicting olfactory dysfunction. In this cross-sectional, retrospective study, olfactory function was assessed by the Sniffin' Sticks 12-item test and multivariate logistic regression analyses were carried out. Receiver operating characteristic curves were plotted to derive accuracy and cutoff values for the JESREC scores of the olfactory dysfunction criterion. A total of 354 patients [mean (SD) age, 50.0 (14.9) years; 41.8% women] were included in the final analysis. The prevalence of olfactory dysfunction was 46.3%. Individuals who had olfactory dysfunction were more likely to be male (64.6% vs. 52.6%), have eosinophilic chronic rhinosinusitis (ECRS) (39.0% vs. 7.9%), have a longer course of CRS (2.3 years vs. 1.5 years), have higher JESREC scores (8.5 vs. 4.5), and have higher proportions of nasal polyps (78.7% vs. 18.9%) and peripheral eosinophilia (3.3% vs. 1.4%). In logistic analysis, the percentage of eosinophils (1.25, 1.13-1.37), JESREC score (1.31, 1.22-1.40), bilateral lesion (2.06, 1.25-3.41), nasal polyps (15.83, 9.23-27.16), CT shadow (2.73, 1.69-4.43), and ECRS (6.86, 3.68-12.80) were associated with olfactory dysfunction in CRS patients after controlling for covariates, while peripheral neutrophils were not significant. In addition, the area under the curve was 0.778 and the cutoff value for JESREC score for olfactory dysfunction was defined as 5.5. Peripheral eosinophilia and high JESREC scores were significantly associated with the risk of olfactory dysfunction in CRS patients, and special attention should be paid to patients with a JESREC score ≥6.

Evidence for a role of metformin in preventing olfactory dysfunction among older adults.

Olfactory dysfunction (OD) is increasingly recognized as a hallmark of unhealthy aging and is intimately associated with mortality, but therapies remain elusive. Recognizing the increased prevalence of OD in individuals with diabetes, and the potential anti-aging effects of metformin, we studied the association of metformin use with OD. Cross-temporal study of participants from Waves 2 (2010-11) and 3 (2015-16) of the National Social Life, Health, and Aging Project (NSHAP), a nationally representative cohort study of community-dwelling older adults. We included participants with diabetes who had complete data on olfaction and relevant covariates at Wave 2 and were not lost to follow-up at Wave 3. Olfactory identification (OI), the ability to identify the odorant, and olfactory sensitivity (OS), the ability to detect the presence of an odorant, were tested. Weighted multivariable logistic regression was used to study the association between metformin use at Wave 2 (baseline) and odds of having impaired OI/OS at Wave 3, adjusted for age, sex, race/ethnicity, education, smoking, BMI, HbA1c, years since diabetes diagnosis, and insulin use. Among 228 participants with diabetes (mean age=70 years, 53% female, 21% Black), 112 (49%) used metformin at baseline. Relative to nonusers, users had 58% lower odds of impaired OI and 67% lower odds of impaired OS at Wave 3. Among participants with normal baseline OS (N=62), users had 97% lower odds of impaired OS at Wave 3. Metformin use is associated with lower odds of OD among individuals with diabetes, suggesting a potential protective effect on olfaction. Future work including a larger sample and additional information on metformin use is needed to establish whether these findings are independent of diabetic control.

An Explanation for Reports of Increased Prevalence of Olfactory Dysfunction With Omicron: Asymptomatic Infections.

The prevalence of olfactory dysfunction (OD) in people infected with the Omicron variant is substantially reduced compared with previous variants. However, 4 recent studies reported a greatly increased prevalence of OD with Omicron. We provide a likely explanation for these outlier studies and reveal a major methodological flaw. When the proportion of asymptomatic infections is large, studies on the prevalence of OD will examine and report predominantly on nonrepresentative cohorts, those with symptomatic subjects, thereby artificially inflating the prevalence of OD by up to 10-fold. Estimation of the true OD prevalence requires representative cohorts that include relevant fractions of asymptomatic cases.

Exploring Olfactory Dysfunction as a Marker of Frailty and Postoperative Outcomes in Head and Neck Cancer

Olfactory dysfunction (OD) is increasingly recognized as a robust marker of frailty and mortality. Despite broad recognition of frailty as a critical component of head and neck cancer (HNC) care, there is no standardized frailty assessment. To assess the prevalence of OD and its association with frailty and postoperative outcomes in HNC. In this prospective cohort study with enrollment between February 17, 2021, to September 29, 2021, at a tertiary academic medical center, 85 eligible adult patients with primary, treatment-naive HNC of mucosal or cutaneous origin were included. Patients with a history of COVID-19, neurocognitive, or primary smell/taste disorders were excluded. Prospective olfactory assessments (self-reported, visual analog scale [VAS] and psychophysical, University of Pennsylvania Smell Identification Test [UPSIT]) with concurrent frailty assessment (Risk Analysis Index [RAI]) were used. Olfactory-specific quality of life (QOL) was examined with brief Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS). The primary outcome was the prevalence of OD as assessed by VAS (0-10, no to normal smell) and UPSIT (0-40, higher scores reflect better olfaction) and its association with frailty (RAI, 0-81, higher scores indicate greater frailty). For surgical patients, secondary outcomes were associations between OD and postoperative length of stay (LOS), 30-day postoperative outcomes, and QOD-NS (0-21, higher scores indicate worse QOL). Among 51 patients with HNC (mean [SD] age, 63 [10] years; 39 [77%] male participants; 41 [80%] White participants), 24 (47%) were frail, and 4 (8%) were very frail. Despite median (IQR) self-reported olfaction by VAS of 9 (8-10), 30 (59%) patients demonstrated measured OD with psychophysical testing. No meaningful association was found between self-reported and psychophysical testing (Hodges-Lehmann, <0.001; 95% CI, -2 to 1); a total of 46 (90%) patients did not report decreased olfaction-specific QOL. Median UPSIT scores were lower in frail patients (Hodges-Lehmann, 6; 95% CI, 2-12). Multivariate modeling demonstrated severe microsmia/anosmia was associated with 1.75 (95% CI, 1.09-2.80) times odds of being frail/very frail and approximately 3 days increased LOS (β, 2.96; 95% CI, 0.29-5.62). Although patients with HNC are unaware of olfactory changes, OD is common and may serve as a bellwether of frailty. In this prospective cohort study, a dose-dependent association was demonstrated between increasing degrees of OD and frailty, and the potential utility of olfaction was highlighted as a touchstone in the assessment of HNC frailty.

Reduction in olfactory dysfunction prevalence among patients with diabetes taking metformin.

Metformin treatment is associated with reduced olfactory dysfunction (OD) in diabetic patients Metformin may possess potential protective effects on olfaction beyond glycemic control.

Olfactory recovery following omicron variant infection: a psychophysical prospective case-control study with six-month follow up.

This study aimed to evaluate the recovery of olfactory function at six months in individuals infected with the coronavirus disease 2019 omicron variant, using psychophysical tests. A prospective case-control study that included severe acute respiratory syndrome coronavirus-2 patients infected in February and March 2022 was conducted. Patients underwent the Sniffin' Sticks test within 10 days of infection and again after at least 6 months. The olfactory scores were compared with those of a control group. In all, 102 patients and 120 controls were enrolled in the study. At baseline, 26 patients (25.5 per cent) self-reported smell loss. The median threshold, discrimination and identification score was 33.6 (interquartile range, 12.5) for the cases and 36.5 (interquartile range, 4.38) for the controls (p < 0.001). Based on the threshold, discrimination and identification scores, 12 controls and 34 patients reported olfactory dysfunction (p < 0.001). Eighty cases underwent re-evaluation at six months; the median threshold, discrimination and identification score was 37.1 (interquartile range, 4.75) with no significant differences compared with the controls. Six months after infection, the prevalence of olfactory dysfunction in patients did not differ significantly from the control population.

Olfactory dysfunction during the COVID-19 era: Prevalence and prognosis for recovery of sense of smell, Eastern region, Saudi Arabia

Objective: There is a strong association between the onset of COVID-19 and olfactory dysfunction (OD) during infection or postinfection as a complication. This study is dedicated to measuring the prevalence of olfactory impairment and its clinical course among patients after COVID-19 infection. Methodology: A cross-sectional study was performed on patients with laboratory-confirmed COVID-19 infection. All participants had completed a validated questionnaire to evaluate the clinical course of OD. Results: Among the 305 participants, 138 reported sudden loss of smell. The mean time between the confirmation of COVID-19 and the onset of OD was 3.59 days. Olfactory impairment, accompanied by other symptoms prior to loss of smell, was reported in 67 participants and as an isolated disorder in 21 participants. Those affected reported nasal obstruction before loss of smell. A total of 138 participants complained of persistence of loss of smell even after the resolution of other symptoms. There is not a statistically significant relationship between the time of loss of smell relative to the confirmation of COVID-19 and the time of resolution of OD. In terms of gender, the prevalence of OD is equal among males and females, and results showed no significant relationship between them. Conclusions: The prevalence of OD is considered a complication among patients with COVID-19. The prognosis for spontaneous recovery from OD is favorable. Due to the lack of an objective measure for olfactory testing, further studies are needed to objectively measure the alteration of the smell.

The prevalence of olfactory dysfunction and its associated factors in patients with COVID-19 infection: A Hospital-based study

Background: The coronavirus disease of 2019 (COVID-19) is a global viral pandemic that originated in East Asia (China) and is quickly spreading to every corner of the globe. In Bangladesh, no research has been conducted on olfactory dysfunction in COVID-19 infected patients and its associated factors. We aimed to determine the correlation between olfactory dysfunction (OD), particularly anosmia and COVID-19 infected patients’ demographic and clinical characteristics. Methods: We conducted a hospital based prospective observational study. We collected patients’ information, including laboratory-confirmed COVID-19 test results from a COVID dedicated hospital, Square Hospitals Ltd., Dhaka, Bangladesh. We used the Pearson Chi-square test and logistic regression model to assess the associations between demographic and clinical characteristics and OD (i.e. anosmia). Results: Out of 600 COVID-19 positive patients, 38.7% were diagnosed with OD. We found that patients’ age, smoking status, cough, dyspnea, sore throat, asthenia, and nausea or vomiting were significantly associated with anosmia. We observed smoking patients were 1.73 times more likely to experience anosmia than non-smoking patients Odd ratio (OR)=1.73, 95% confidence interval (CI) = 1.01-2.98]. Interestingly, our data showed that the risk of developing anosmia was greater in younger patients than in older patients, and this risk decreased as age increased (OR) range for different age groups: 1.26 to 1.08]. In addition, patients who complained of asthenia had a significantly double risk of developing anosmia [OR = 1.96, CI = 1.23-3.06]. Conclusions: Our study shows that 38.7% of patients diagnosed with OD. Patients’ age, smoking status, and asthenia are significantly positively associated with anosmia. Since anosmia can be a significant marker for the diagnosis of COVID-19, we suggest regular screening of OD in patients with early symptoms of COVID-19, particularly younger patients, smokers, and who complained of asthenia. Bangladesh Journal of Medical Science Vol. 22 No. 01 January’23 Page : 195-204

Long-term Consequences of COVID-19: Chemosensory Disorders.

A number of sequelae after acute coronavirus disease 2019 (COVID-19) significantly affect the quality of life of patients. The chemosensory disorders including olfactory dysfunction (OD) and gustatory dysfunction (GD) are two of the commonest symptoms complained by patients with COVID-19. Although chemosensory function has been reported improved in over 60% of COVID-19 patients in a short time after acute infection, it may last as a major symptom for patients with long COVID-19. This narrative review discussed current literatures on OD and GD in long COVID-19 including the prevalence, risk factors, possible mechanisms, and potential therapies. Although the prevalence of OD and GD has declined continuously after acute COVID-19, a considerable number of patients had persistent chemosensory disorders 3months to 2years after symptom onset. Female gender, initial severity of dysfunction, nasal congestion, emotional distress and depression, and SARS-CoV-2 variants have been identified as risk factors for persistent OD and GD in long COVID-19. The pathogenesis of OD and GD in long COVID-19 remains unknown, but may be analogous to the persistent OD and GD post common respiratory viral infection. Corticosteroids and olfactory training might be a potential choice regarding the treatment of lasting OD and GD after SARS-CoV-2 infection; however, more studies are needed to prove it. OD and GD are common long-term consequences of COVID-19 and influenced by gender, initial severity of dysfunction, emotional distress and depression, and SARS-CoV-2 variants. More studies are needed to illustrate their pathogenesis and to establish therapeutic strategies.

Clinical Features Assessment and Effect of Olfactory Training among COVID-19 Patients in the Kingdom of Saudi Arabia

Coronavirus disease (COVID-19) was announced in Mar 2020 as a global pandemic. Olfactory dysfunction (OD) is a common consequence. Therefore, the present study assessed the prevalence of OD and other clinical features among COVID-19 patients in Saudi Arabia along with the effect of olfactory training. Eighty-two patients participated in this study and their demographics as well as clinical features, effect of olfactory training, and recovery time were assessed using a questionnaire. Patients with OD went through self olfactory training by sniffing essential oils twice a day for 30 or 40 sec, followed by 10 or 20 sec break then repeat for 5 or 10 min for 6 weeks. Our results revealed that 62% had OD in which 41% had hyposmia and 21% had anosmia, while 38% had normosia. Additionally, 80% lost their olfactory function during infection period, whereas 20% lost it post-infection. Most patients recovered their olfactory function after 2 weeks (39%). Moreover, 71% restored their olfactory function naturally, whilst 27% restored it by olfactory training, and 2% did not experience improvement. The frequently reported symptoms among OD patients included headache (62%), sore throat (60%), fever (54%), and cough (48%). Whereas the common symptoms among patients without OD are bone pain (38%), diarrhea (24%) anorexia (21%), and vomiting (11%). This study highlights the prevalence and underlying mechanism of OD and the potential effect of olfactory training using essential oils due to their unharmful bioactive molecules. The likely of OD makes it a recommended diagnostic tool in early COVID-19 stage.

Persisting chemosensory dysfunction in COVID-19 - a cross-sectional population-based survey.

Chemosensory dysfunction (CD) has been reported as a common symptom of SARS-CoV-2 infection, but it is not well understood whether and for how long changes of smell, taste and chemesthesis persist in infected individuals. Unselected adult residents of the German federal state of Schleswig-Holstein with Polymerase Chain Reaction (PCR)-test-confirmed SARS-CoV-2 infection were invited to participate in this large cross-sectional study. Data on the medical history and subjective chemosensory function of participants were obtained through questionnaires and visual analogue scales (VAS). Olfactory function (OF) was objectified with the Sniffin Sticks test (SST), including threshold (T), discrimination (D) and identification (I) test as well as summarized TDI score, and compared to that in healthy controls. Gustatory function (GF) was evaluated with the suprathreshold taste strips (TS) test, and trigeminal function was tested with an ampoule containing ammonia. Between November 2020 and June 2021, 667 infected individuals (mean age: 48.2 years) were examined 9.1 months, on average, after positive PCR testing. Of these, 45.6% had persisting subjective olfactory dysfunction (OD), 36.2% had subjective gustatory dysfunction (GD). Tested OD, tested GD and impaired trigeminal function were observed in 34.6%, 7.3% and 1.8% of participants, respectively. The mean TDI score of participants was significantly lower compared to healthy subjects. Significant associations were observed between subjective OD and GD, and between tested OD and GD. Nine months after SARS-CoV-2 infection, OD prevalence is significantly increased among infected members of the general population. Therefore, OD should be included in the list of symptoms collectively defining Long-COVID.

Prevalence of olfactory dysfunction in D614G, alpha, delta and omicron waves: a psychophysical case-control study.

The purpose of this study was to compare the prevalence of olfactory dysfunction (OD) at different stages of the COVID-19 pandemic by evaluating subjects diagnosed with SARS-CoV-2 infection during the Omicron wave with psychophysical tests and comparing the results with those obtained from patients infected during the D614G, Alpha and Delta waves and with those of a control group. The study included adult patients diagnosed with SARS-CoV-2 infection. Depending on the time of diagnosis, the subjects were divided into four study groups: D614G; Alpha, Delta and Omicron variant groups. A group of uninfected individuals was used as control. All subjects underwent psychophysical evaluation of the olfactory function with the Connecticut Chemosensory Clinical Research Center olfactory test (D614G and Alpha groups) or the extended version of the Sniffin'Sticks test (Delta, Omicron and control groups). 372 cases (134 D614G group, 118 Alpha group, 32 in Delta group and 88 Omicron group) were recruited and evaluated within 10 days of infection, alongside 80 controls. Patients self-reported olfactory loss in 72.4% of cases in the D614G group, in 75.4% of cases in the Alpha group, in 65.6% of cases in the Delta group and in 18.1% in the Omicron group. Psychophysical evaluation revealed a prevalence of OD: 80.6%, 83.0%, 65.6% and 36.3% in the D614G, Alpha, Delta and Omicron group respectively. The differences between the D614G, Alpha and Delta groups were not statistically significant. The Omicron group demonstrated a significantly lower prevalence of OD than the other variants but still significantly higher than the controls. During the Omicron wave OD was less prevalent than during the D614G, Alpha and Delta periods. One-third of patients have reduced olfactory function on psychophysical evaluation during the Omicron wave. Our results should be considered with caution as the VOC has not been determined with certainty.

Management of Post-COVID-19- Related Olfactory Dysfunction

Evidence suggests that the prevalence of olfactory dysfunction (OD) occurs in 50% of patients with COVID-19.Emerging data suggest a high rate of early and spontaneous recovery, but approximately 10% of patients showed no improvement at 4-6 weeks after recovery. Given the high prevalence of COVID-19, a considerable number of patients will experience this morbidity.Thus, the main goal of this review is to define a guideline protocol for patients recovered from COVID-19, who present with olfactory dysfunction. In those cases, it is important to start by classifying the severity of this change and rule out other possible underlying etiologies, which may require further investigation.The treatment with best results is olfactory training. Additionally, the use of nasal corticosteroid spray or omega-3 supplementation may be recommended.It should be noted that those conclusions are based upon clinical trials whose patients were infected by viruses other than SARS-CoV-2. This way, further study and validation regarding the treatment of this condition should be carried out as the pandemic progresses.

Long-term quality-of-life impairment in patients with more than 1-year COVID-19-related olfactory dysfunction.

Long-term quality-of-life impairment in patients with more than 1-year COVID-19-related olfactory dysfunction.

Parosmia assessment with structured questions and its functional impact in patients with long-term COVID-19-related olfactory dysfunction.

Parosmia assessment with structured questions and its functional impact in patients with long-term COVID-19-related olfactory dysfunction.

Olfactory Dysfunction and Phantosmia in Patients With COVID-19 in Northern Iran

Background: One of the most common symptoms of COVID-19 infection is Olfactory Dysfunction (OD). Objectives: This study aims to investigate OD and phantosmia in COVID-19 cases from northern Iran. Materials &amp; Methods: In this cross-sectional study, participants were 400 patients with COVID-19 infection in Rasht, Iran from March 2019 to September 2020. All the patients were evaluated in terms of OD and then followed up for 3 months face-to-face, by telephone call, or online. Results: Among 400 patients, 37.75% had OD (19% hyposmia, 10.75% primary phantosmia, and 8% anosmia) during the initiation of the disease, but 121 (30.25%) including nearly 65% of anosmic and/or hyposmic cases reported phantosmia at different time intervals of followup visits. Moreover, 65.38% of patients reported acute onset of OD. The prevalence of OD was significantly higher in patients aged &lt;40 years (P=0.001) and in females (P=0.002). OD improved in about 90% of patients within 3 months. Peripheral oxygen saturation was better in anosmic cases and C-reactive protein level was higher in normosmic cases at their first visit. No significant difference was found in terms of other laboratory results. Conclusion: OD is a common complication of COVID-19 infection, but seems not to be permanent. It is more common in young patients, females, and those with mild COVID-19 infection.