Olfactory function trends in COVID-19 patients: a prospective cohort study

Clinical factors influencing olfactory performance in patients with persistent COVID‐19 smell loss longer than 1 year

“…Although past studies have reported a possible influence of parosmia 14 , 15 and phantosmia 10 on smell recovery our analysis did not confirm that. Similarly, in contrast with previous authors 11 , 12 , 13 , 14 , 39 we did not find any effect of age on smell recovery. On the other hand, we found a positive significant effect of presence of comorbidities on discrimination scores ( p = .048) which in some aspects corroborates previous results from Chudzik et al 11 who concluded that the risk of developing long‐COVID smell loss is greater in people with less comorbidities.…”

“…Conversely, our study showed a positive significant influence of smoking on discrimination scores ( p = .03). Even though this could have been caused by a sample bias in our study, our finding corroborates previous results from Akbari and colleagues 39 who found significant better identification scores in smokers but also previous studies 41,42 which reported that COVID-19-related OD is less frequent in patients with a smoking habit. Prevalence of parosmia in our population (80%) was higher when compared to previous studies, although this varies widely across different studies in the literature and reported to be between 43% at 6 months and 70.9% when evaluated at 1 year.…”

“…All our patients experienced a severe smell loss following SARS‐CoV‐2 infection and this corroborates previous studies suggesting that subjects with greater initial severity of dysfunction are less likely to recover their olfaction 5 . The role of smoking on smell recovery is still controversial 5,39 . A study conducted by Hummel et al 40 on 894 patients before the COVID‐19 pandemic concluded that smoking is a negative predictive factor for recovery by increasing the nasal irritation and causing subsequent nasal obstruction.…”

“… 5 The role of smoking on smell recovery is still controversial. 5 , 39 A study conducted by Hummel et al 40 on 894 patients before the COVID‐19 pandemic concluded that smoking is a negative predictive factor for recovery by increasing the nasal irritation and causing subsequent nasal obstruction. Conversely, our study showed a positive significant influence of smoking on discrimination scores ( p = .03).…”