Predictors for the Development of Hypoxia or Prolonged Acute Symptoms among Non-Hospitalized Mild-to-Moderate Patients with Coronavirus Disease 2019

Predictors for the Development of Hypoxia or Prolonged Acute Symptoms among Non-Hospitalized Mild-to-Moderate Patients with Coronavirus Disease 2019

Yasunori Tadano,¹ Tetsuya Akaishi,^1,2 Satoko Suzuki,^1,3 Rie Ono,^1,3 Natsumi Saito,^1,3 Ryutaro Arita,^1,2,3 Takeshi Kanno,¹ Junichi Tanaka,⁴ Akiko Kikuchi,^1,2,3Minoru Ohsawa,^1,2,3 Shin Takayama,^1,2,3 Michiaki Abe,¹ Ko Onodera¹ and Tadashi Ishii^1,2

¹Department of Education and Support for Regional Medicine, Tohoku University Hospital, Sendai, Miyagi, Japan
²Department of Integrative and Kampo Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
³Department of Kampo Medicine, Tohoku University Hospital, Sendai, Miyagi, Japan
⁴Office of Medical Education, Tohoku University School of Medicine, Sendai, Miyagi, Japan

The coronavirus disease 2019 (COVID-19) pandemic remains a global public health concern. The clinical course and risk of developing severe illness among patients with COVID-19 who are at low-risk of severe COVID-19 remain uncertain. This retrospective cohort study from an isolation facility for low-risk COVID-19 patients in Japan evaluated the potential risks for severe disease with hypoxia (SpO₂ 93%) or experiencing prolonged isolation period longer than 14 days with persistent acute symptoms. The study was performed before the spread of the alpha variant in the country and before the start of a nationwide mass vaccination campaign against COVID-19. Among the 929 participants with reliable outcome data regarding the development of hypoxia, 63 (6.8%) developed severe disease with hypoxia during their stays at the facility. Higher age [adjusted odds ratio (aOR), 1.08; 95% confidence interval (CI), 1.06-1.10] and male sex (aOR, 4.70; 95% CI, 2.39-9.22) were associated with this outcome. As for the experience of prolonged isolation period, higher age (aOR, 1.02; 95% CI, 1.01-1.04), atopic diseases (aOR, 1.69, 95% CI, 1.09-2.64), presence of cough at onset (aOR, 1.64; 95% CI, 1.09-2.48), and prescription of oral antibiotics before positive test results for COVID-19 (aOR, 2.37; 95% CI, 1.33-4.22) were associated with this outcome. In summary, 5-10% of low-risk COVID-19 patients later develop hypoxia. Older age and male sex were associated with both the development of hypoxia and prolonged acute symptoms. The unnecessary prescription of antibiotics before COVID-19 diagnosis may prolong COVID-19 symptoms.

Key words —— coronavirus disease 2019 (COVID-19); hypoxia; low-risk group; predictors; prolonged acute symptoms

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Tohoku J. Exp. Med., 2023 July, 260(3), 231-244.

Correspondence: Tetsuya Akaishi, Department of Education and Support for Regional Medicine, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.

e-mail: t-akaishi@med.tohoku.ac.jp