Chemosensory assessment and impact on quality of life in neurosensorial cluster of the post COVID 19 syndrome

Abstract

COVID-19 pandemic brought chemosensory impairment to the forefront of medicine, revealing gaps in the knowledge of pathophysiological mechanisms, true prevalence and preventive/therapeutic alternatives. This is a sub-study of the ORCHESTRA cohort focusing on post-COVID-19 chemosensory symptoms. Risk factors for neurosensorial cluster of post-COVID-19 syndrome (NSc-PCS) were assessed through multivariable analysis. Psychophysical validated tests were applied on a sub-population of 50 patients. Qualitative chemosensory symptoms as well as nasal and oral chemesthesis were evaluated through anamnestic interview and the quality of life through the SF-36 questionnaire. Chemosensory symptoms evolution and olfactory training's outcome were assessed through phone-call interviews. Out of 1187 patients (female, N = 630), 550 (47%) presented NSc-PCS, with a lower risk for older age and monoclonal antibodies treatment, and a higher risk in females (p < 0.001). Out of the 50 patients evaluated with psychophysical tests, 66% showed smell reduction with a qualitative alteration in 50% of hyposmic and 35% of normosmic patients. Hypogeusia was present in 14 (28%) of the patients assessed, with 56% showing a qualitative alteration; 53% of normogeusic patients presented qualitative disorders. NSc-PCS has a complex, fluctuating, multifaceted presentation. Quantifying and characterizing COVID-19-related chemosensory impairment is key to understand underlying mechanisms and to develop preventive and therapeutic treatment.

Keywords: Chemosensory impairment; Post-COVID syndrome; SARS-CoV-2 long-term sequelae.

Fig. 1

Flow chart of the study. NSc-PCS: neurosensorial cluster of post-COVID syndrome, including smell and/or taste impairment; SRC: Self-Reported Chemosensory impairment group; PAC: Psychophysical Assessment of Chemosensory impairment group.

Fig. 2

Prevalence of self-reported chemosensory symptoms in the acute phase (top panel) and at the follow-up (bottom panel), by the time of the acute phase and annotated with the waves and variants dominating in Europe, based on the Nextstrain prevalence data. Only groups with at least 10 patients are shown.

Fig. 3

Composite scores for SSET (top panel) and TST (lower panel). Each bar corresponds to a single patient. Colours correspond to the measurements of score composites. Each plot is divided into sections according with the cut offs defining normogeusia and hypogeusia for gustatory function and normosmia, hyposmia and anosmia for olfactory function. Each bar is annotated with the summary score. As the SSET cut-off was adjusted by age (see “Methods”) the plot is not strictly monotonous.