Table 3.

Estimated and measured mean 24‐h urinary creatinine and sodium excretion by diuretic use

	Entire sample		Complete collectors		Incomplete collectors		P b
	Mean (SD)	P a	Mean (SD)	P a	Mean (SD)	P a
Mean 24‐h Cr exc (mg/d)	N = 99		N = 63		N = 36
Measured 24‐h	1510.9 (534.7)	<.0001	1682.1 (495.4)	.89	1211.3 (469.7)	<.0001	<.0001
Estimated 24‐h (algorithm)	1689.0 (451.5)		1685.4 (470.7)		1695.3 (422.2)		.92
On Diuretic	N = 60		N = 33		N = 27
Measured 24‐h	1499.9 (480.7)	<.0001	1664.5 (449.0)	.89	1298.6 (446.9)	<.0001	.003
Estimated 24‐h	1701.3 (428.4)		1660.2 (425.1)		1751.4 (435.0)		.42
Not on Diuretic	N = 39		N = 30		N = 9
Measured 24‐h	1527.9 (614.9)	.008	1701.5 (549.1)	.75	949.1 (461.5)	<.0001	.001
Estimated 24‐h	1670.2 (490.1)		1713.2 (522.2)		1526.8 (349.9)		.32
Mean 24‐h Na exc (mEq/d)	N = 99		N = 63		N = 36
Measured 24‐h uncorrected	143.3 (71.9)	<.0001	156.2 (73.8)	.70	120.6 (63.3)	<.0001	.02
Measured 24‐h corrected	162.3 (75.8)		157.2 (76.1)		171.2 (75.6)		.38
On Diuretic	N = 60		N = 33		N = 27
Measured 24‐h uncorrected	145.5 (65.3)	<.0001	156.5 (64.7)	.88	132.2 (64.6)	<.0001	.15
Measured 24‐h corrected	167.4 (71.9)		156.0 (64.0)		181.3 (79.5)		.18
Not on Diuretic	N = 39		N = 30		N = 9
Measured 24‐h uncorrected	139.9 (81.8)	.01	156.0 (83.7)	.54	86.0 (46.1)	.002	.02
Measured 24‐h corrected	154.4 (81.8)		158.4 (88.6)		140.9 (55.5)		.58

^aComparing within entire sample, complete collectors and within incomplete collectors, difference between measured and estimated 24‐h Cr exc and for difference between uncorrected and corrected 24‐h Na exc, by paired samples t test.

^bComparing complete vs incomplete collectors by independent samples t test.