Table 3.

Levels of conventional biomarkers by time point

Conventional Biomarker	Day 0: Premarathon (n=22)	Day 1: Immediately Postmarathon (n=22b)	Day 2: Postmarathon (n=22)	Overall Pa
Serum Creatinine (mg/dL)	0.81 (0.76, 0.95)	1.28 (1.09, 1.54)*	0.90 (0.80, 0.90)	<0.001
Serum creatine kinase (U/l)	86 (74, 159)	268 (242, 344)	722 (434, 844)*	<0.001
FENa (%)	0.82 (0.61, 1.11)*	0.23 (0.11, 0.29)	0.22 (0.18, 0.41)	<0.001
Urine albumin (mg/dL)	0.50 (0.50, 0.50)	3.50 (1.69, 6.53)*	0.54 (0.50, 0.68)	<0.001
Urine albumin-creatinine ratio (mg/g)	0.01 (0.01, 0.01)	0.02 (0.02, 0.05)*	0.01 (0.00, 0.01)	<0.001
Urine Microscopy score ≥1	2 (9%)*	13 (65%)	13 (59%)	<0.001
Urinalysis
Specific Gravity	1.02 (1.01, 1.02)	1.02 (1.01, 1.03)	1.02 (1.01, 1.02)	0.2
pH	7.0 (6.0, 7.0)*	5.5 (5.5, 7.0)	6.0 (5.5, 6.5)	0.002
Blood				0.3
0	19 (86%)	13 (65%)	18 (82%)
1	2 (9%)	4 (20%)	3 (14%)
2	0	1 (5%)	0
3	0	2 (10%)	0
4	1 (5%)	0	1 (5%)
Nitrite positive	0	1	0	0.3
Protein				0.03
0	21 (95%)	12 (60%)	18 (82%)
1	1 (5%)	2 (10%)	4 (18%)
2	0	4 (20%)	0
3	0	1 (5%)	0
4	0	1 (5%)	0
Ketones				<0.001
0	22 (100%)	9(45%)	17 (77%)
1	0	8 (40%)	5 (23%)
2	0	3 (15%)	0
Leukocyte Esterase				0.7
0	16 (73%)	15 (75%)	18 (82%)
1	4 (18%)	4 (20%)	1 (5%)
2	1 (5%)	0	1 (5%)
3	1 (5%)	1 (5%)	2 (9%)

FENa, fractional excretion of sodium;

Note: Values for categorical variables are given as number (percentage); for continuous variables, as median [interquartile range].

^aOverall p-values were obtained via Kruskal-Wallis Test for continuous variables, and X² test statistic was used for categorical variables.

^bOnly 20 urine samples were available on Day 1 since 2 runners refused to provide urine.

^*Value is significantly different compared to the other two time points.