Patient burden of chemosensory dysfunction and long COVID.

INTRODUCTION: Chemosensory dysfunction (CD), particularly olfactory and gustatory dysfunction, is a common symptom of SARS-CoV-2 infection. While often transient, some patients develop persistent dysfunction. The long-term relationship between persistent CD, long COVID (LC) and quality of life (QoL) remains unclear. This study aimed to evaluate CD recovery four years after infection and its association with LC symptoms and QoL. METHODS: In this prospective cohort study, 356 individuals with sudden CD during the COVID-19 pandemic completed a questionnaire four years after symptom onset. The survey assessed CD recovery, LC symptoms and QoL using validated self-report items. Outcomes were compared between participants with recovered versus persistent CD. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. RESULTS: Only 43% reported full recovery of CD after four years. Persistent dysfunction was most common among participants aged 45-59 years (68%). Participants with persistent CD were significantly more likely to report LC symptoms, particularly fatigue (OR = 4.33), memory difficulties (OR = 3.30) and insomnia (OR = 3.39), each affecting more than 30% of this group. QoL scores indicated a greater impact on physical than emotional well-being. CONCLUSIONS: A substantial proportion of respondents continued to experience CD and other LC symptoms four years after infection. These findings highlight the need for long-term clinical awareness and further research on post-viral CD. FUNDING: None. TRIAL REGISTRATION: Not relevant.