FIGURE 3.

Key study characteristics assessed in feasibility assessment: a) coronavirus disease 2019 (COVID-19) disease severity (reported by 13 out of 52 studies), b) oxygen status (reported by 29 out of 52 studies), c) duration of hospitalisation (reported by 30 out of 52 studies) and d) intensive care unit (ICU) admission (reported by 34 out of 52 studies). Disease severity was recorded either at admission or during the period of hospitalisation; oxygen status was recorded over the period of hospitalisation. Duration of hospitalisation was reported by studies as either mean or median; in the heterogeneity assessment these values were assumed to be equivalent as per standard practice and the standard deviation was calculated from the interquartile range for studies reporting the median. IMV: invasive mechanical ventilation.