Table 2.

Patients’ characteristics according to urine-concentrating features

Variables	Group 1	Group 2	P value group 1 vs. group 2	Group 3	Group 4	P value group 3 vs. group 4	P value all
	ADH <5 pg/ml Max Uosm ≥ 600 mOsm/kgH2O	ADH ≥5 pg/ml Max Uosm ≥ 600 mOsm/kgH2O		ADH ≥5 pg/ml Max Uosm < 600 mOsm/kgH2O	ADH <5 pg/ml Max Uosm < 600 mOsm/kgH2O
n	63	65		54	12
Age, yrs	50 [38–63]	40 [31–58]	0.03	60 [48–66]	51 [41–57]	0.05	<0.001
Male sex, n (%)	25 (39.7)	27 (41.5)	1	15 (27.8)	4 (33.3)	1	0.4
Lithium treatment duration, yrs	3 [2–7]	3 [1–7]	0.4	18 [10–28]	13 [4–17]	0.06	<0.001
Sustained-release formulation n (%)	42 (68.9)	50 (78.1)	0.3	25 (46.3)	8 (66.7)	0.3	0.003
Daily dose, mg/d	800 [500–1000]	950 [750–1200]	<0.001	750 [500–1000]	800 [575–1000]	0.5	0.003
Serum lithemia, mmol/l	0.65 [0.50–0.85]	0.77 [0.64–0.87]	0.04	0.72 [0.60–0.89]	0.76 [0.60–0.88]	0.8	0.2
24-hour urinary output, ml/d	1812 [1471–2312]	1558 [1337–2060]	0.08	2883 [2022–3513]	3026 [1755–3786]	1	<0.001
Fasting thirst score, 0–10 scale	6 [4–7]	6 [4–8]	0.6	5 [3–7]	5 [4–5]	0.1	0.04
Fasting natremia, mmol/l	141 [140–142]	141 [140–142]	0.9	143 [141–144]	141 [141–142]	0.1	<0.001
Maximal Uosm, mOsm/kgH2O	814 [709.50–898]	826 [739–885]	1	435 [318–516]	541 [483–560]	0.03	<0.001
Plasma vasopressin, pg/ml	3.39 [2.90–4.20]	7.80 [5.80–12.50]	<0.001	10.55 [6.81–16.73]	3.69 [2.48–4.38]	<0.001	<0.001
Plasma copeptin, pmol/l	8.12 [6.73–10.89]	13.30 [9.92–19.25]	<0.001	25.87 [18.30–45.18]	9.73 [3.04–16.80]	0.03	<0.001
mGFR, ml/min per 1.73 m2	78.0 [72.4–90.4]	88.0 [76.8–94.2]	0.1	54.4 [43.1–72.2]	81.1 [58.6–89.4]	0.02	<0.001

ADH, antidiuretic hormone; mGFR, measured glomerular filtration rate; Q, quartile; Uosm, urine osmolality.

Data are expressed as median (Q1–Q3) or number (percentage). Comparisons were performed using Mann–Whitney test when 2 groups were compared and Kruskal–Wallis test when comparing all the groups for quantitative variables. χ² test was performed for categorical variables.