Factors associated with anosmia recovery rate in COVID‐19 patients

Abstract

Objectives: The present study aimed to assess the 4-and 8-week recovery rate of anosmia and determine the factors associated with recovery in COVID-19 patients. Method: This retrospective study was conducted from December 2020 to March 2021. RT-PCR-proven COVID-19 adult patients (over 18 years of age) with a positive history of anosmia were included in this study. Anosmia was assessed based on the COVID-19 Anosmia Reporting Tool. The recovery rate of anosmia after 4 and 8 weeks were evaluated, and the relationship between the patients' recovery and their clinical and demographic data was assessed. Results: A total of 235 patients were included. Their mean age (±SD) was 43.95 ± 15.27 years. Anosmia recovery was reported in 207(88.51%) and 219 (93.19%) participants till 4 and 8 weeks. The mean recovery time was 19.42 ± 8.81 days. The result of logistic regression showed that smoking (P = .031; OR = 10.813), ageusia (P = .002; OR = 5.340), headache (P = .006; OR = 0.243), and nasal discharge (P < .001; OR = 0.080) were significantly associated with 4 weeks anosmia recovery.The only risk factor which was associated with a lower rate of 8 weeks anosmia recovery was presence of nasal discharge (OR = 0.106, P = .002). Conclusion:The only risk factor which was associated with a lower rate of 8 weeks anosmia recovery was presence of nasal discharge. Our result demonstrated that although smoking was associated with higher recovery rate till 4 weeks, it could not be considered as a protective factor after 8 weeks. More studies are recommended to investigate the relationship between anosmia and the associated factors by consideration of both short-and long-term recovery rates and assess the possible mechanisms that could justify this association.

Analysis of Prevalence and Predictive Factors of Long-Lasting Olfactory and Gustatory Dysfunction in COVID-19 Patients

“…In our study, a multiple logistic regression model associated higher ages (OR = 0.20; 95% CI: [0.07, 0.56], p = 0.002) and a duration of loss of smell longer than four weeks (OR = 0.27; 95% CI: [0.10, 0.76], p = 0.013) with a higher risk of persistent dysfunction. We did not find any association between the presence of comorbidities and the persistence of a chemosensory impairment, in concordance with previous studies, where the prevalence of comorbidities was even higher than that of 12.8% found in our study [ 23 , 28 , 29 , 44 ]. In addition, the analysis of the effects of other nasal and systemic symptoms during the infection has led to divergent results in different studies.…”

“…In addition, the analysis of the effects of other nasal and systemic symptoms during the infection has led to divergent results in different studies. Whereas some authors relate these symptoms to worsened results in the recovery of smell and taste both in the short and long term [ 26 , 39 , 43 , 44 ], others have not found any such relation [ 31 , 35 , 38 ]. In our study, we have shown that suffering from fever at the baseline was independently associated with a higher odds ratio for chemosensory recovery (OR = 3.19; 95% CI: [1.28, 7.94], p = 0.0126).…”

Impaired olfaction post-coronavirus disease 2019: a systematic review of smell recovery predictive factors

“…It is believed that nasal congestion causes “conductive” olfactory disorders due to coronavirus infection [ 16 ]. While a study stated nasal symptoms are statistically significant with smell and taste loss [ 28 ], this is in contrast to the study by Babaei et al [ 15 ] which stated that the presence of nasal discharge was not correlated with olfactory dysfunction. Shortness of breath: Shortness of breath is often found in severe COVID-19 symptoms.…”

“…Several researchers have hypothesized that the central mechanism of trigeminal damage occurs due to the connection of the olfactory system with the trigeminal nerve itself, with overlapping activation in areas such as the piriform cortex, ventral insula, and medial frontal gyrus [ 35 ]. Cigarette smoking: Cigarette smoking is a predictor of recovery of olfactory function 4 weeks after coronavirus infection [ 15 ]. Several researchers have cited lower rates of COVID-19 infection among individual smokers.…”

“…Cigarette smoking: Cigarette smoking is a predictor of recovery of olfactory function 4 weeks after coronavirus infection [ 15 ]. Several researchers have cited lower rates of COVID-19 infection among individual smokers.…”