Table 7.

Parameter estimates for mixed-effects meta-regression on AUC.

Subset	Variable	Value	Estimate	SE	p-value
Linear classifiers	Region	Europe - reference	0.826	0.029	< 0.001
		USA	-0.006	0.017	0.715
		China	0.057	0.013	< 0.001
		Other region	0.024	0.016	0.130
	Number of patients		-0.001	0.001	0.040
	Rate of severe cases		-0.196	0.168	0.247
	Rate of severe cases squared		0.241	0.289	0.406
	Mean age difference		0.005	0.001	< 0.001
Machine learning and Neural Network	Region	Europe - reference	0.908	0.029	< 0.001
		USA	0.020	0.023	0.381
		China	0.074	0.019	0.001
		Other region	-0.010	0.021	0.650
	Number of patients		-0.001	0.001	0.142
	Rate of severe cases		-0.189	0.162	0.250
	Rate of severe cases squared		0.168	0.231	0.470
	Mean age difference		< 0.001	0.001	0.785