Factors involved in the improvement of prolonged symptoms in patients with COVID-19 treated with Japanese traditional (Kampo) medicine: A single-center, prospective, observational study

Patients with prolonged symptoms of COVID-19 (PSC) show various symptoms, especially fatigue, which affect their activities of daily living and inhibit their return to social life. As there is no standard treatment for PSC, we developed a treatment regimen that includes Japanese traditional (Kampo) medicine according to patient symptoms and condition. This study aimed to investigate the progression of symptoms in patients with PSC using this treatment regimen and to assess differences in background factors that affect the improvement of symptoms in patients. We conducted a prospective, observational study and collected data from patients with PSC who visited a hospital in Japan between May 2022 and December 2023. The patient performance status (PS, 0-9) and 16 symptoms on a numerical rating scale (NRS, 0-10) were recorded at each visit. A total of 114 patients were analyzed. The group with a first visit general fatigue score equal to or greater than the median (GMGF group) took more time to achieve PS ≤ 2 (hazard ratio [95% confidence interval (CI)], 0.405 [0.253-0.650], P < .001) and the end of visit milestone (0.283 [0.150-0.532], P < .001) compared to the group with a first visit general fatigue score less than the median (LMGF group). The group with ≥90 days from the onset to the first visit (≥90 days group) reached the end of visit milestone significantly later (0.510 [0.267-0.974], P = .041) than the group with <90 days from the onset (the <90 days group). The odds ratios (95% CI) for achieving PS ≤ 2 and the end of visit milestone within 3 months of the first visit in the GMGF group were 0.140 (0.046-0.425, P < .001) and 0.148 (0.058-0.380, P < .001), respectively. The ≥90 days group experienced difficulty in achieving the end of visit milestone within 3 months of the first visit (odds ratio [95% CI], 0.430 [0.179-1.035], P = .06). Patients with PSC who have a high general fatigue score at their first visit may have difficulty improving their symptoms. Early treatment, including Kampo medicine, can promote the improvement of PSC symptoms.