Olfactory function trends in COVID-19 patients: a prospective cohort study

Area of Science:

• Otorhinolaryngology
• Infectious Diseases
• Neurology

Background:

• Olfactory and taste dysfunction are common symptoms in COVID-19 patients.
• Understanding the long-term impact on smell is crucial for patient recovery and quality of life.

Purpose of the Study:

• To objectively evaluate olfactory threshold and identification in Iranian COVID-19 survivors.
• To assess the prevalence and influencing factors of olfactory dysfunction post-COVID-19.

Main Methods:

• Prospective cohort study of 111 clinically recovering COVID-19 patients (2020-2021).
• Olfactory function assessed at baseline, 4-6 weeks, and 12 weeks using the Saba Sabalan kit (threshold) and the Iranian version of the Pennsylvania Smell Identification Test (IR-SIT).

Main Results:

• Men (mean threshold 7.2) had better olfactory thresholds than women (6.6).
• Older age was negatively associated with good olfaction at baseline (OR=0.93, p=0.05).
• Only 29.7% of patients had normal olfactory function by IR-SIT; smoking was linked to lower baseline IR-SIT scores (adjusted Beta <0.001, p=0.03).

Conclusions:

• Objective tests are reliable for assessing olfactory dysfunction in COVID-19 patients.
• Olfactory impairment is prevalent post-COVID-19, with varying impacts based on demographics and lifestyle factors.
• Further research is recommended to explore long-term olfactory outcomes and potential interventions.