Consultant Sengkang General Hospital Houston, Texas
Introduction: Olfactory dysfunction (OD) and gustatory dysfunction (GD) are highly prevalent in COVID-19 patients. This study aims to characterize long term recovery of olfaction and taste in these patients, by using patient-reported subjective data and objective testing.
Methods: A total of 40 COVID-19 positive patients who presented to the Emergency Department between 14 Feb to 31 Jul 2020 were recruited. Medical charts were reviewed for OD and GD at time of presentation. After at least 9 months, patients were contacted by phone and answered a questionnaire. Patients were asked to rate their overall olfactory and gustatory function on an 11-point Likert scale, and reported the presence of other symptoms such as cacosmia or phantosmia. This was followed up with objective olfactory testing using the Brief Smell Identification Test (BSIT).
Results: The prevalence of self-reported acute OD and GD at diagnosis of COVID-19 was 62.5% and 57.5% respectively. The median time interval between COVID-19 diagnosis and the study evaluation was 41 weeks, where 80.0% and 92.5% of patients subjectively reported complete recovery of OD and GD respectively. Thirty three patients completed the BSIT. In this group, although 78.8% had reported perfectly normal olfaction (rated 10 out of 10) and 93.9% had reported good olfaction (rated 7 and above), only 51.5% had BSIT scores within normal range. Objective BSIT scores did not correlate well with self-reported olfaction (r=0.246). Age, gender, and severity of initial loss did not have a statistically significant association with recovery rates.
Conclusion: Long term OD and GD affect a significant number of patients, and subjective symptoms may not correlate well with objective test results