COVID-19 anosmia and gustatory symptoms as a prognosis factor: a subanalysis of the HOPE COVID-19 (Health Outcome Predictive Evaluation for COVID-19) registry

Abstract

Olfactory and gustatory dysfunctions (OGD) are a frequent symptom of coronavirus disease 2019 (COVID-19). It has been proposed that the neuroinvasive potential of the novel SARS-CoV-2 could be due to olfactory bulb invasion, conversely studies suggest it could be a good prognostic factor. The aim of the current study was to investigate the prognosis value of OGD in COVID-19. These symptoms were recorded on admission from a cohort study of 5868 patients with confirmed or highly suspected COVID-19 infection included in the multicenter international HOPE Registry (NCT04334291). There was statistical relation in multivariate analysis for OGD in gender, more frequent in female 12.41% vs 8.67% in male, related to age, more frequent under 65 years, presence of hypertension, dyslipidemia, diabetes, smoke, renal insufficiency, lung, heart, cancer and neurological disease. We did not find statistical differences in pregnant ( p = 0.505), patient suffering cognitive ( p = 0.484), liver ( p = 0.1) or immune disease ( p = 0.32). There was inverse relation (protective) between OGD and prone positioning (0.005) and death (< 0.0001), but no with ICU (0.165) or mechanical ventilation (0.292). On univariable logistic regression, OGD was found to be inversely related to death in COVID-19 patients. The odds ratio was 0.26 (0.15–0.44) ( p < 0.001) and Z was − 5.05. The presence of anosmia is fundamental in the diagnosis of SARS.CoV-2 infection, but also could be important in classifying patients and in therapeutic decisions. Even more knowing that it is an early symptom of the disease. Knowing that other situations as being Afro-American or Latino-American, hypertension, renal insufficiency, or increase of C-reactive protein (CRP) imply a worse prognosis we can make a clinical score to estimate the vital prognosis of the patient. The exact pathogenesis of SARS-CoV-2 that causes olfactory and gustative disorders remains unknown but seems related to the prognosis. This point is fundamental, insomuch as could be a plausible way to find a treatment. Supplementary Information The online version contains supplementary material available at 10.1007/s15010-021-01587-9.

COVID-19 and anosmia: The story so far

“…34 Olfactory and gustatory dysfunctions were also associated with the prognosis of COVID-19 and were negatively associated with mortality in patients with an odds ratio of .26 (.15-.44). 35…”

“…The occurrence and development of COVID-19-induced anosmia are associated with a variety of factors. These factors included smoking habits, 35 type 2 diabetes mellitus, 48 depressed mood, 49 anxiety, 49 gastroesophageal disorders, 50 serum interleukin-6 levels, 51,52 rhinitis, 53 thrombocytopenia, 53 and elevated creatinine. 53 The high prevalence of anosmia in COVID-19 patients with smoking habits may be related to the fact that tobacco causes more severe damage to OE cells.…”

“…53 The high prevalence of anosmia in COVID-19 patients with smoking habits may be related to the fact that tobacco causes more severe damage to OE cells. 35 Reduced first-line defense of nasal immunity in type 2 diabetes mellitus patients increased SARS-CoV-2 susceptibility in the nasal cavity with the unknown cause. 48 The severities of olfactory and gustatory loss was associated with depressed mood and anxiety, indicating that emotional dysfunction may be a symptom of the CNS in COVID-19 patients since SARS-CoV-2 can invade the CNS through the olfactory pathway.…”

How COVID-19 brought smell disorders in the spotlight

“…Although there are numerous studies which imply that anosmia might be a good prognosis factor 17,30 , we must keep in mind that in face of an acute respiratory distress syndrome, anosmia merely goes unreported. This observation is due to the lack of studies that objectively measure the olfactory function in patients with various degree of disease severity.…”

“…It is by now a recognized fact that patients with comorbidities are prone to developing a severe form of COVID-19, and a few studies were made trying to determine the link between comorbidities and olfactory dysfunction 29,30 .…”