Quantitative Olfactory Dysfunction and Parosmia After COVID-19: An Observational Cohort Study

Area of Science:

• Otolaryngology
• Neurology
• Infectious Diseases

Background:

• Olfactory dysfunction (OD) is a prevalent post-COVID-19 condition with unclear long-term outcomes.
• Parosmia, a smell distortion, is a common manifestation of C19OD.

Purpose of the Study:

• Describe patient characteristics in post-COVID-19 OD (C19OD).
• Identify factors influencing parosmia persistence.
• Investigate parosmia's impact on quantitative olfactory function.

Main Methods:

• Longitudinal cohort study of 190 C19OD patients.
• Quantitative olfactory function assessed using the "Sniffin' Sticks" TDI test.
• Parosmia, subjective function, and quality of life (QoL) evaluated over 24 months.

Main Results:

• Parosmia affected 73.7% of patients and was associated with higher TDI scores (p=0.001).
• Patients with quantitative OD reported worse QoL than those with parosmia alone (p=0.008).
• Persistent parosmia showed a trend towards TDI score improvement, with no predictive baseline characteristics.

Conclusions:

• Parosmia is common in C19OD and correlates with better quantitative olfactory function.
• Quantitative OD significantly impacts QoL negatively.
• Parosmia persistence is not predictable by baseline factors but may improve over time.