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. 2023 Jun 15;325(2):F199–F213. doi: 10.1152/ajprenal.00086.2023

Table 2.

Kidney function

Parameter Euhydrated Group
Hypohydrated Group
P Value
All Participants Males Females All Participants Males Females Sex Hydration Sex × Hydration
Estimated glomerular filtration rate, mL/min/1.73 m2 117 (111, 123) 121 (113, 129) 113 (102, 123) 118 (112, 124) 119 (111, 126) 116 (105, 128) 0.2990 0.8323 0.2998
Fractional excretion of Na+, % 1.1 (0.7, 1.5) 1.1 (0.7, 1.4) 1.1 (0.3, 1.9) 0.2 (0.1, 0.2) 0.2 (0.1, 0.2)* 0.2 (0.1, 0.2)* 0.8299 <0.0001 0.9571
Fractional excretion of K+, % 14.9 (10.3, 19.5) 14.2 (9.4, 19.0) 15.7 (6.3, 25.0) 1.9 (1.4, 2.3) 1.5 (1.0, 1.9)* 2.3 (1.5, 3.2)* 0.6244 <0.0001 0.8971
Serum
 Creatinine, mg/dL 0.8 (0.8, 0.9) 0.9 (0.8, 1.0) 0.8 (0.7, 0.9) 0.8 (0.8, 0.9) 0.9 (0.8, 1.0) 0.7 (0.6, 0.8)† 0.0128 0.9156 0.1174
 Na+, mmol/L 142 (141, 143) 142 (140, 144) 142 (140, 143) 144 (143, 146) 144 (142, 146)* 144 (142, 147)* 0.9782 <0.0001 0.7045
 K+, mmol/L 4.2 (4.1, 4.3) 4.1 (4.0, 4.3) 4.2 (4.1, 4.3) 4.2 (4.1, 4.3) 4.2 (4.0, 4.4) 4.2 (4.0, 4.3) 0.9987 0.7610 0.4862
Urine
 Creatinine, mg/dL 85 (62, 108) 102 (66, 138) 68 (38, 98) 259 (220, 297) 302 (235, 369)* 215 (187, 243)*† 0.0039 <0.0001 0.2029
 Na+, mmol/L 29 (21, 37) 31 (19, 42) 28 (15, 41) 88 (76, 99) 84 (62, 106)* 91 (79, 103)* 0.7699 <0.0001 0.4205
 K+, mmol/L 12 (8, 15) 13 (8, 17) 10 (6, 15) 28 (22, 34) 25 (20, 29)* 32 (21, 44)* 0.4017 <0.0001 0.1027

Values are represented as means with 95% confidence intervals in parentheses; n = 22 participants (11 males and 11 females) for urine Na+ and K+ and n = 21 participants (11 males and 10 females) for the remaining data. Data were analyzed using two-way ANOVA with factors of sex and hydration and post hoc Holm–Šídák tests for multiple comparisons.

*Different from the euhydrated group for a given sex (P ≤ 0.0087); †different from males for a given condition (P ≤ 0.0057).