Table-4.

Results of ROC curve analysis of all kidney size parameters.

Imaging parameters	ROC curve analysis		Cutoff value		Percentage sensitivity (CI 95%)	Percentage specificity (CI 95%)
	AUC (95% CI)	p-value	Type	cutoff
Radiography
Average kidney length (cm)	0.68 (0.487–0.873)	0.093	Optimal sensitivity	3.85	60 (32–84)	73 (45–92)
			Maximum specificity	3.48	20 (4–48)	93 (68–100)
K/L2 ratio	0.77 (0.604–0.938)	<0.05	Optimal sensitivity	2.27	67 (33–88)	73 (45–92)
			Maximum specificity	2.04	47 (21–73)	93 (68–100)
Ultrasonography
Average kidney length (cm)	0.72 (0.532–0.908)	<0.05	Optimal sensitivity	3.53	67 (38–88)	73 (45–92)
			Maximum specificity	3.06	20 (4–48)	93 (68–100)
K/AO ratio	0.87 (0.746–0.997)	<0.001	Optimal sensitivity	10.71	80 (52–96)	80 (52–96)
			Maximum specificity	9.99	60 (32–84)	93 (68–100)

ROC=Receiver operating characteristic, CI=Confidence interval, AUC=Area under the curve, K/AO=Kidney length-to-abdominal aortic diameter, K/L2=Kidney length-to-second lumbar length ratio. Receiver operator characteristic analysis was used to identify optimal cut off values. Optimal sensitivity cut off value was determined with the Youden index and likelihood ratio. Maximum specificity cut off value with near 100% specificity