Predictors of Kidney Dimensions Measured by Multi-detector Computed Tomography (MDCT) in 930 Middle-Aged and Elderly Patients

Figures & data

Figure 1. A 79-year-old female patient. Axial computed tomography (CT) image (A). Sagittal oblique (B) and coronal oblique (C) images reformatted according to pole-to-pole length (R1) of left kidney. R1 was measured as 101 mm.

Figure 2. Axial computed tomography (CT) image obtained via pan zooming to kidney; distance up to lateral margin from the level of renal hilus (R2) and bicortical length perpendicular to R2 (R3).

Table 1. General characteristics and renal dimensions of the entire study population [mean ± SD (percentage)].

Parameters	Total	Males	Females
Number of patients (n)	930	432 (46.4%)	498 (53.6%)
Mean age (years)	63 ± 8	64 ± 8	62 ± 8*
Mean body height (cm)	163.8 ± 9.3	169.4 ± 6.5	158.9 ± 8.5*
Mean body weight (kg)	72.1 ± 13.7	72.0 ± 12.9	72.2 ± 14.3
Mean BMI	27.2 ± 11.8	25.0 ± 4.2	29.1 ± 15.4*
Comorbidities (n)
Diabetes mellitus	184 (19.8%)	78 (18.1%)	106 (21.3%)
Hypertension	296 (31.8%)	97 (22.5%)	199 (40%)*
Renal stone disease	126 (13.5%)	65 (15%)	61 (12.2%)
Benign prostatic hyperplasia	150 (16.1%)	150 (34.7%)	−
Previous genitourinary operation	62 (6.7%)	38 (8.8%)	24 (4.8%)
Frequent analgesic use	220 (23.7%)	87 (20.1%)	133 (26.7%)^**
Creatinine clearance (eGFR)
MDRD (mL/min) >90	379 (41.3%)	199 (47%)	180 (36.4%)*
60–90	481 (52.5%)	222 (52.5%)	259 (52.4%)*
30–60	57 (6.2%)	2 (0.5%)	55 (11.1%)*
CG (mL/min)   >90	449 (49.6%)	189 (44.6%)	260 (54.1%)*
60–90	361 (39.9%)	197 (46.5%)	164 (34.1%)*
30–60	95 (10.5%)	38 (9%)	57 (11.9%)*
Mean eGFR (mL/min)
CG	94.1 ± 33.3	89.9 ± 14.3	97.8 ± 37.1*
MDRD	90.5 ± 35.3	91.6 ± 21.1	89.6 ± 43.6*
Creatinine (mg/dL)	0.79 ± 0.18	0.87 ± 0.16	0.72 ± 0.17*
Urea (mg/dL)	28.9 ± 11.1	30.7 ± 11.0	27.3 ± 11.0*
Parenchymal width (mm)
Right	13.3 ± 1.8	13.7 ± 1.8	12.9 ± 1.7*
Left	13.0 ± 1.0	13.4 ± 1.9	12.7 ± 1.8*
Pole-to-pole length (R1) (mm)
Right	109 ± 11.5	110.6 ± 11.6	107.7 ± 11.3*
Left	110.7 ± 12.0	112.4 ± 11.9	109.1 ± 11.8*
R2	49.8 ± 5.5	51.1 ± 5.8	48.6 ± 4.9*
L2	49.8 ± 5.6	51.6 ± 5.5	48.3 ± 5.2*
R3	49.9 ± 7.0	50.7 ± 6.5	49.29 ± 7.4*
L3	52.0 ± 7.3	53.6 ± 7.3	50.66 ± 7.0*

Notes: MDRD, modification of diet in renal disease; CG, Cockcroft–Gault; eGFR, estimated glomerular filtration rate; BMI, body mass index.

* and ^**Denote significance at < 0.001 and < 0.01 levels, respectively.

Figure 3. Scatter plot graph showing relationship of Cockcroft–Gault (CG)-estimated glomerular filtration rate (eGFR) with increasing age. There is a negative correlation between CG-eGFR and age.

Figure 4. Scatter plot graph showing relationship of R1 size with Cockcroft–Gault (CG)-estimated glomerular filtration rate (eGFR). There is a positive correlation between R1 and CG-eGFR.

Table 2. Correlations between age, height, weight, serum urea, creatinine, CG-GFR, and MDRD-GFR with renal dimensions (Pearson’s correlation).

	RPW	R1	R2	R3	LPW	L1	L2	L3
Age	−0.215^**	−0.124^**	−0.071*	−0.010	−0.247^**	−0.125^**	−0.091^**	−0.048
Height	0.229^**	0.175^**	0.219^**	0.119^**	0.168^**	0.178^**	0.194^**	0.132^**
Weight	0.250^**	0.249^**	0.311^**	0.301^**	0.260^**	0.229^**	0.295^**	0.322^**
Urea	−0.017	−0.074*	−0.029	−0.025	−0.049	−0.059	−0.056	−0.003
Creatinine	−0.031	−0.134^**	−0.045	−0.020	−0.085^**	−0.136^**	−0.042	0.016
CG-GFR	0.270^**	0.302^**	0.266^**	0.197^**	0.294^**	0.283^**	0.267^**	0.210^**
MDRD-GFR	0.045	0.110^**	0.081*	0.030	0.139^**	0.154^**	0.131^**	0.075*

Notes: RPW, right paranchymal width; CG, Cockcroft–Gault; MDRD, modification of diet in renal disease; GFR, glomerular filtration rate; LPW, left paranchymal width. *and ^**Denote significance at the 0.05 (two-tailed) and 0.01 levels (two-tailed), respectively.

Table 3. Logistic regression model (enter method) showing independent relationship of some variables with renal dimensions RPW, R1, R2, and R3.

		B	p	OR ratio	95% CI for OR
Right	Sex	0.99	<0.001	2.7	1.9–3.8
paranchymal	CG (>90 mL/min)		<0.001
width	CG (90–60 mL/min)	0.79	<0.001	2.2	1.5–3.1
	CG (60–30 mL/min)	1.082	<0.001	2.9	1.6–5.2
R1	Sex	0.58	<0.000	1.8	1.2–2.5
	Diabetes mellitus	−0.45	<0.015	0.6	0.4–0.9
	CG (>90 mL/min)		<0.001
	CG (90–60 mL/min)	1.06	<0.001	2.9	2.0–4.0
	CG (60–30 mL/min)	1.78	<0.001	5.9	3.3–10.6
R2	Sex	1.15	<0.001	3.1	2.2–4.5
	Diabetes mellitus	−0.77	<0.001	0.4	0.3–06
	Renal stone	−0.48	<0.031	0.6	0.4–0.9
	CG (>90 mL/min)		<0.001
	CG (90–60 mL/min)	0.99	<0.001	2.7	1.8–3.8
	CG (60–30 mL/min)	1.66	<0.001	5.2	2.8–9.8
R3	Sex	0.86	<0.001	2.3	1.6–3.3
	Diabetes mellitus	−0.73	<0.001	0.4	0.3–0.6
	Renal stone	−0.54	<0.011	0.5	0.3–0.8
	CG (>90 mL/min)		<0.001
	CG (90–60 mL/min)	0.55	<0.002	1.7	1.2–2.4
	CG (60–30 mL/min)	0.79	<0.007	2.2	1.2–3.9

Note: OR, odds ratio; CI, confidence interval; CG, Cockcroft–Gault.

Figure 5. Scatter plot graph showing relationship of age with R1 size. There is a weak negative correlation between R1 and age.