Real-world observational data on olfactory dysfunction of the Smell & Taste Clinic of UZ Leuven (Belgium) from 2021-2024.

Abstract

Background: The COVID-19 pandemic led to a surge in olfactory dysfunction (OD), increasing the need for specialized care. Thi study explores the prevalence, characteristics, and clinical implications of OD in a specialized Smell & Taste Clinic established at the ENT-HNS department of the University Hospitals Leuven (UZ Leuven) in 2021.

Methodology: We included consecutive patients with OD in the observational longitudinal ProspeRo'Scent registry at UZ Leuven between September 2021 and April 2024. Chemosensory assessment was done with psychophysical tests (Sniffin' Sticks TDI and Taste sprays) and questionnaires.

Results: Of the 203 unique, consecutive patients, COVID-19-associated OD (C19OD) was the predominant etiology (50.2%), followed by idiopathic (25.1%), and post-traumatic (8.9%) OD. Parosmia was present in 60.2% of patients, with the highest prevalence in C19OD cases (80.9%). Sniffin' Sticks TDI testing indicated that patients with parosmia had better olfactory thresholds and discrimination scores than patients without. During follow-up (n=116; average 7.7 months), 31% of C19OD patients exhibited clinically relevant improvement in TDI scores, compared to 13% for the other etiologies. Quality of life, as assessed by sQOD-NS, was not significantly different between etiologies but correlated with higher parosmia scores.

Conclusions: C19OD patients suffered more from parosmia, correlating with worse quality of life, but had better baseline TDI scores and demonstrated a higher likelihood of clinically relevant improvement over time compared to other etiologies.