Table 2.

Harrell's C index of the full, training and validation datasets by model

		Harrell's C
		Statistic	(95% CI)
Model 1 (Basic model, KFRE four variables)	Full data	0.911	(0.904, 0.918)
	Training set	0.912	(0.902, 0.922)
	Validation set	0.908	(0.898, 0.918)
Model 2	Full data	0.940	(0.935, 0.945)
	Training set	0.939	(0.930, 0.947)
	Validation set	0.947	(0.939, 0.955)
Model 3	Full data	0.951	(0.947, 0.955)
	Training set	0.952	(0.946, 0.958)
	Validation set	0.951	(0.944, 0.959)
Among CKD participants
Model 1	Full data	0.877	(0.867, 0.887)
	Training set	0.877	(0.863, 0.891)
	Validation set	0.879	(0.865, 0.892)
Model 2	Full data	0.907	(0.898, 0.915)
	Training set	0.910	(0.899, 0.921)
	Validation set	0.905	(0.893, 0.917)
Model 3	Full data	0.923	(0.916, 0.930)
	Training set	0.924	(0.914, 0.933)
	Validation set	0.924	(0.914, 0.934)
Among non-CKD participants
Model 2	Full data	0.835	(0.815, 0.855)
	Training set	0.828	(0.799, 0.857)
	Validation set	0.846	(0.821, 0.871)
Model 3	Full data	0.873	(0.859, 0.887)
	Training set	0.867	(0.842, 0.892)
	Validation set	0.882	(0.858, 0.905)

We defined CKD stages by proteinuria and eGFR, which we determined with the Chronic Kidney Disease Epidemiology Collaboration equation.

CI: confidence interval; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate.

Model 1: basic model, Kidney Failure Risk Equations model (KFRE) four variables: age, sex, eGFR and proteinuria.

Model 2: basic model + health history + lifestyle risk factors: model 1 + educational level, smoking status, physical activity, BMI, resting heart rate, hypertension medication and diabetes medication.

Model 3: full model: model 2 + systolic blood pressure, diastolic blood pressure, blood glucose, triglyceride, BUN, serum albumin, white blood cell, hemoglobin, urine glucose and urine specific gravity.