Clinical features of patients who visited the outpatient clinic for long COVID in Japan.

BACKGROUND

The clinical course, comorbidity, and management of symptoms after the acute phase of coronavirus disease 2019 (COVID-19) remain controversial.

METHODS

This was a descriptive case series study, examining the characteristics of patients with longstanding symptoms related to COVID-19 who visited our outpatient clinic between 1 June and 31 December 2021. We analyzed patients' background, chief complaints, clinical course after COVID-19 onset, and clinical examination results.

RESULTS

A total of 90 patients with a mean age of 39.8 years were confirmed as having long COVID. The median time between diagnosis of COVID-19 and visiting our clinic was 66.8 days, and 89 patients (98.9%) were unvaccinated. Depression was the most common comorbidity (nine patients, 10.0%). The most common chief complaint was disturbance of smell and/or taste (35, 38.9%), followed by memory disturbance (22, 24.4%) and fatigue (29, 31.1%). Head MRI was performed for 42 (46.7%) patients, and the most common finding was sinusitis (four patients). Olfactory testing was conducted in 25 patients (27.8%) using a T&T olfactometer, and 14 patients (56%) had mild olfactory impairment. Of the five odors in the T&T, recognition of β-phenylethyl alcohol was most impaired.

CONCLUSIONS

This study describes the basic characteristics of long COVID in Japan. It suggests that long COVID is complex because it results in a wide range of symptoms.