Table 2

Linear regression analyses using METs as the outcome variable

Crude regressionSex-adjusted regression
Coefficient (95% CI)P valueCoefficient (95% CI)P value
Sex (female)−3.12 (−5.14 to 1.11)0.0039
Haemoglobin (g/L)0.074 (0.031 to 0.12)0.0010.055 (0.01 to 0.10)0.024
SaO2 (%)0.28 (0.008 to 0.55)0.0440.29 (0.037 to 0.55)0.026
CaO2*0.00073 (0.00037 to 0.0011)0.00020.00062 (0.0002 to 0.001)0.003
  • Normal quantile plots (online supplementary figure 3) supported the use of METs (‘1st‘ METs) as the dependent variable.

  • *CaO2 unit mL of oxygen/L.

  • CaO2, arterial oxygen content; METs, metabolic equivalents; SaO2, oxygen saturation.