Table 2.

Associations of UKV with continuous serum potassium (mEq/l) on the basis of 3-time and 7-time measurements in all CKD patients by GEE regression analyses

Models	Tertiles of UKV on the basis of 24-hour urine collections			P-for-trend	Per 10 mEq/d increase in continuous UKVe
	Low tertile	Middle tertile	High tertile
Analyzed patients (N = 290) with 3-time measurements (870 observations)
UKV on the basis of 24-hour urine collections, mEq/d	$\le$ 26.0	26.0–39.9	>39.9
N of observations	287	288	295		870
Adjusted means (95% CI) of serum potassiuma	4.40 (4.33–4.47)	4.54 (4.49–4.60)	4.70 (4.63 to 4.77)
Mean differences (95% CI) in serum potassium
Model 1b	0 [Ref]	0.09 (0.004 to 0.17)	0.14 (0.04 to 0.24)	0.009	0.08 (0.05–0.11)
Model 2c	0 [Ref]	0.16 (0.08 to 0.24)	0.28 (0.18 to 0.38)	P < 0.001	0.12 (0.09–0.15)
Model 3d	0 [Ref]	0.15 (0.06 to 0.23)	0.30 (0.20 to 0.41)	P < 0.001	0.12 (0.09–0.15)
Analyzed patients (N = 220) with 7-time measurements (1540 observations)
UKV on the basis of 24-hour urine collections, mEq/d	$\le$ 27.3	27.3–39.9	> 39.9
N of observations	508	510	522		1540
Adjusted means (95% CI) of serum potassium a	4.42 (4.36–4.47)	4.53 (4.48–4.58)	4.65 (4.59–4.7)
Mean differences (95% CI) in serum potassium
Model 1b	0 [Ref]	0.15 (0.07–0.23)	0.23 (0.13–0.32)	P < 0.001	0.09 (0.06–0.12)
Model 2c	0 [Ref]	0.19 (0.11–0.26)	0.28 (0.18–0.38)	P < 0.001	0.11 (0.08–0.14)
Model 3d	0 [Ref]	0.11 (0.05–0.18)	0.23 (0.15–0.32)	P < 0.001	0.10 (0.07–0.13)

ACE, angiotensin-converting-enzyme inhibitor; ARB, angiotensin II receptor blocker; CI, confidence interval; CKD, chronic kidney disease; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate; GEE, generalized estimating equation; MRA, mineralocorticoid receptor antagonists; SBP, systolic blood pressure; SGLT2i, sodium-glucose cotransporter 2 inhibitors; UKV, 24-hour urinary potassium excretion.

^aMultivariable-adjusted means (95% CI) were based on estimated marginal means obtained from Model 3.

^bModel 1 was unadjusted.

^cModel 2 was adjusted for age, sex, eGFR, and urine creatinine.

^dModel 3 was adjusted for Model 2 covariates, urine protein, diabetes (defined by any medication use of diabetes and diabetic nephropathy as an underlying disease for CKD), hypertension (defined by any use of antihypertensive, or SBP ≥ 140 mm Hg or DBP ≥ 90 mm Hg, or nephrosclerosis as an underlying disease for CKD), medication use that could increase serum potassium level (including ACEi/ARB, MRA, renin inhibitors, potassium supplement medication), medication use that could decrease serum potassium level (including diuretics except MRA, SGLT2i, potassium binder, liquorice extract, and bicarbonate), and previous values of serum potassium and UKV.

^eThis corresponds to a β coefficient of a continuous UKV on serum potassium.