Predictive accuracy of 4C Mortality Score and Acute Physiology and Chronic Health Evaluation scores for mortality in COVID-19 patients admitted to intensive care unit

Table 1 Calculation of 4C Mortality Score

Variable	4C Mortality Score
Age (years)
< 50	-
50-59	+2
60-69	+4
70-79	+6
≥ 80	+7
Sex at birth
Female	-
Male	+1
1Number of comorbidities
0	0
1	+1
≥ 2	+2
Respiratory rate (breaths/minute)
< 20	-
20-29	+1
≥ 30	+2
Peripheral oxygen saturation on room air (%)
≥ 92	-
< 92	+2
Glasgow coma scale score
15	-
< 15	+2
Urea (mmol/L)
< 7	-
7-14	+1
> 14	+3
C reactive protein (mg/L)
< 50	-
50-99	+1
≥ 100	+2

¹Comorbidities were defined by using Charlson comorbidity index.