Preliminary study regarding the predicted body weight-based dexamethasone therapy in patients with COVID-19 pneumonia

Background The RECOVERY clinical trial reported that 6 mg of dexamethasone once daily for up to 10 days reduces the 28-day mortality in patients with coronavirus disease 2019 (COVID-19) receiving respiratory support. In our clinical setting, a fixed dose of dexamethasone has prompted the question of whether inflammatory modulation effects sufficiently reduce lung injury. Therefore, preliminary verification on the possibility of predicted body weight (PBW)-based dexamethasone therapy was conducted in patients with COVID-19 pneumonia. Methods This single-center retrospective study was conducted in a Japanese University Hospital to compare the treatment strategies/management in different periods. Consecutive patients (n = 90) with COVID-19 pneumonia requiring oxygen therapy and were treated with dexamethasone between June 2020 and May 2021 were analyzed. Initially, 60 patients administered a fixed dexamethasone dose of 6.6 mg/day were defined as the conventional group, and then, 30 patients were changed to PBW-based therapy. The 30-day discharged alive rate and duration of oxygen therapy were analyzed using the Kaplan–Meier method and compared using the log-rank test. The multivariable Cox regression was used to evaluate the effects of PBW-based dexamethasone therapy on high-flow nasal cannula (HFNC), noninvasive ventilation (NIV), or mechanical ventilation (MV). Results In the PBW-based group, 9, 13, and 8 patients were administered 6.6, 9.9, and 13.2 mg/day of dexamethasone, respectively. Additional respiratory support including HFNC, NIV, or MV was significantly less frequently used in the PBW-based group (P = 0.0046), with significantly greater cumulative incidence of being discharged alive and shorter oxygen demand within 30 days (92 vs. 89%, log-rank P = 0.0094, 90 vs. 92%, log-rank P = 0.0002, respectively). Patients treated with PBW-based therapy significantly decreased the use of additional respiratory support after adjusting for baseline imbalances (adjusted odds ratio, 0.224; 95% confidence interval, 0.062–0.813, P = 0.023). Infection occurred in 13 (21%) and 2 (7%) patients in the conventional and PBW-based groups, respectively (P = 0.082). Conclusions In patients with COVID-19 pneumonia requiring oxygen therapy, PBW-based dexamethasone therapy may potentially shorten the length of hospital stay and duration of oxygen therapy and risk of using HFNC, NPPV, or MV without increasing serious adverse events or 30-day mortality.