Table 2.

Distribution of vital signs and clinical laboratory measurements of 23 runners in the 2017 Hartford Marathon by AKI status

VariableTotal, n=23No AKI, n=10AKI, n=12P Value
1 d before race (day 0)
 Heart rate64 (57–73)69 (60–76)63 (55–69)0.16
 Systolic BP, mm Hg132 (121–137)130 (121–132)134 (121–138)0.51
 Serum creatinine, mg/dl0.90 (0.75–0.98)0.87 (0.76–0.98)0.88 (0.75–0.96)0.87
 BUN-to-creatinine ratio17 (15–20)19 (15–22)17 (13–19)0.31
 Serum sodium, mmol/L139 (138–140)140 (139–141)139 (138–140)0.08
 CPK, U/L105 (68–147)109 (64–167)91 (73–144)0.82
 Hemoglobin, g/dl15 (14–16)15 (14–16)15 (13–16)0.65
 Copeptin, pmol/L3.12 (2.69–3.44)3.12 (2.69–3.36)3.12 (2.71–3.92)0.86
Soon after race (day 1)
 Heart rate107 (101–126)112 (104–127)107 (100–122)0.70
 Systolic BP, mm Hg107 (102–115)114 (111–123)103 (93–107)0.006
 Serum creatinine, mg/dl1.28 (1.06–1.44)1.03 (0.96–1.19)1.42 (1.28–1.59)0.001
 BUN-to-creatinine ratio15 (13–18)17 (13–23)15 (12–18)0.21
 Serum sodium, mmol/L141 (139–143)141 (140–143)141 (139–143)0.81
 CPK, U/L286 (239–403)286 (250–423)281 (211–342)0.59
 Hemoglobin, g/dl14 (14–16)14 (14–15)15 (14–16)0.76
 Urine microscopy score >117 (74%)9 (90%)8 (67%)0.31
 Urine protein, mg/dl15 (65%)7 (70%)8 (67%)0.89
 Serum osmolality, mosm/kg303 (296–310)303 (296–308)303 (298–310)0.74
 Urine osmolality, mosm/kg523 (348–651)500 (156–714)564 (505–573)0.74
 Copeptin, pmol/L49.8 (11.3–81.5)11.3 (6.6–43.7)79.9 (25.2–104.4)0.02
 Sweat sodium loss, g2.34 (1.15–4.2)1.4 (0.97–2.8)3.41 (1.7–4.8)0.06
 Sweat volume loss, L2.47 (1.02–3.89)1.66 (0.72–2.84)3.89 (1.49–5.09)0.03
 Median core body temperature, °F38.4 (38.4–39.3)38.8 (38.4–39.4)38.4 (38.4–38.6)0.62
 Peak core body temperature, °F39.2 (38.6–40.2)39.0 (38.6–40.3)39.4 (39.0–40.2)0.55
 Total fluid intake, L1.5 (1.2–2.0)1.7 (1.4–2.5)1.8 (0.9–2.0)0.41
 Total sodium intake, g0.57 (0.26–0.96)0.57 (0.26–0.96)0.57 (0.22–0.91)0.96
 Net weight loss, kg1.8 (1.5–2.5)1.9 (1.5–2.3)1.6 (1.1–2.9)0.76
 Net fluid balance, L−0.67 (−2.95–0.65)−0.06 (−3.62–0.94)−0.96 (−2.22 to −0.28)0.41
 Net sodium balance, g−1.89 (−3.39 to −0.66)−1.16 (−3.34 to −0.25)−2.22 (−3.43 to −1.81)0.19
1 d after race (day 2)
 Heart rate62 (57–72)67 (59–73)60 (57–69)0.34
 Systolic BP, mm Hg128 (121–142)129 (116–149)125 (122–140)0.45
 Serum creatinine, mg/dl0.89 (0.75–0.93)0.88 (0.80–0.93)0.89 (0.73–0.93)0.64
 BUN-to-creatinine ratio20 (15–23)17 (15–22)21 (18–23)0.19
 Serum sodium, mmol/L137 (136–138)138 (136–138)137 (135–138)0.22
 CPK, U/L856 (542–1621)788 (474–1455)1339 (616–2063)0.22
 Hemoglobin, g/dl14 (14–15)14 (13–15)14 (14–16)0.52
 Copeptin, pmol/L3.57 (2.73–7.03)3.56 (2.51–4.01)4.78 (3.35–7.05)0.37
  • In healthy adults, 13 pmol/L represents the 97.5th percentile of copeptin. Data are shown as median (interquartile range), and frequencies are presented as n (%). P values were calculated using the Wilcoxon rank sum test. Runners with AKI had significantly lower systolic BPs immediately after the race with higher copeptin levels as well as higher sweat volume losses and a trend toward higher sweat sodium losses. Core body temperature was not significantly different between runners with and without AKI. This suggests that runners with AKI had hypovolemia as evidenced by increased sweat losses and lower systolic BP leading to copeptin stimulation and likely, hypoperfusion to the kidneys secondary to kidney vasoconstriction in the setting of hypovolemia and renin-angiotensin-aldosterone system activation. CPK, creatine phosphokinase.