Inpatient management and post-discharge outcomes of hyperkalemia

Figures & data

Table 1. Patient characteristics during the six months prior to the inpatient admission by hyperkalemia severity during the inpatient stay

	Mild Hyperkalemia	Moderate Hyperkalemia	Severe Hyperkalemia	P-values
	>5.0–5.5 mEq/L	>5.5–6.0 mEq/L	>6.0 mEq/L	Mild vs. Moderate	Mild vs. Severe
	(N = 15,083)	(N = 4,136)	(N = 2,574)
Demographics
Age (years), mean (SD)	64.6 (16.4)	63.8 (16.8)	63.0 (16.7)	< 0.01 *	< 0.001 *
Female, n (%)	6,858 (45.5%)	1,892 (45.7%)	1,118 (43.4%)	0.77	0.06
Race, n (%)				<0.001 *	<0.001 *
White	8,923 (59.2%)	2,257 (54.6%)	1,342 (52.1%)
Black or African American	5,691 (37.7%)	1,738 (42.0%)	1,138 (44.2%)
Asian, other, or missing	469 (3.1%)	141 (3.4%)	94 (3.7%)
Comorbidities
CKD (stage 3–5), n (%)	6,001 (39.8%)	1,737 (42.0%)	1,167 (45.3%)	< 0.05 *	<0.001 *
CKD stage among patients with CKD, n (%)				< 0.001 *	< 0.001 *
Stage 3	3,371 (56.2%)	867 (49.9%)	492 (42.2%)
Stage 4	996 (16.6%)	301 (17.3%)	229 (19.6%)
Stage 5 or ESKD	1,634 (27.2%)	569 (32.8%)	446 (38.5%)
ESKD, n (%)	559 (3.7%)	192 (4.6%)	183 (7.1%)	< 0.01 *	< 0.001 *
Acute kidney injury, n (%)	2,250 (14.9%)	672 (16.2%)	463 (18.0%)	< 0.05 *	< 0.001 *
Type 2 diabetes, n (%)	4,881 (32.4%)	1,366 (33.0%)	911 (35.4%)	0.43	< 0.01 *
Heart failure, n (%)	3,423 (22.7%)	1,013 (24.5%)	615 (23.9%)	< 0.05 *	0.19
Hypertension, n (%)	8,754 (58.0%)	2,397 (58.0%)	1,536 (59.7%)	0.94	0.13
Charlson Comorbidity Index (CCI), mean (SD)	2.1 (2.4)	2.2 (2.4)	2.3 (2.5)	0.26	< 0.05 *
Previous Treatments Used, n (%)
Any RAASi use	4,004 (26.5%)	1,125 (27.2%)	671 (26.1%)	0.41	0.63
SPS or patiromer	550 (3.6%)	202 (4.9%)	197 (7.7%)	< 0.01 *	< 0.01 *
Any diuretics use	4,559 (30.2%)	1,290 (31.2%)	777 (30.2%)	0.24	0.99
Any dialysis	636 (4.2%)	214 (5.2%)	195 (7.6%)	< 0.01 *	< 0.001 *
Potassium Labs during Baseline
Number of potassium labs, mean (SD)	7.1 (14.9)	7.6 (16.5)	7.3 (14.9)	0.09	0.54
Proportion with at least 1 potassium lab, n (%)	10,464 (69.4%)	2,827 (68.4%)	1,690 (65.7%)	0.21	< 0.01 *
Among patients with at least 1 potassium lab
Any potassium labs >5 mEq/L, n (%)	1,483 (14.2%)	489 (17.3%)	416 (24.6%)	< 0.001 *	< 0.001 *
Number of potassium labs >5 mEq/L, mean (SD)	0.8 (2.3)	1.0 (2.8)	1.6 (3.9)	< 0.001 *	< 0.001 *

*p-values<0.05 were considered statistically significant; p-values for categorical variables were calculated using chi-squared tests; p-values for continuous variables were calculated using ANOVA tests. CKD, chronic kidney disease; ESKD, end-stage kidney disease; N, number; RAASi, renin-angiotensin-aldosterone system inhibitor; SD, standard deviation; SPS, sodium polystyrene sulfonate

Table 2. Comparison of clinical characteristics among patients with mild, moderate, and severe hyperkalemia during the inpatient stay^a.

	Mild Hyperkalemia	Moderate Hyperkalemia	Severe Hyperkalemia	p-values
	>5.0–5.5 mEq/L	>5.5–6.0 mEq/L	>6.0 mEq/L	Mild vs. Moderate	Mild vs. Severe
	(N = 15,083)	(N = 4,136)	(N = 2,574)
Death during Inpatient Stay, n (%)
Patients who died	1,852 (12.3%)	643 (15.5%)	502 (19.5%)	< 0.001 *	< 0.001 *
Length of Inpatient Stay, mean (SD)
Total days in inpatient care	9.1 (7.5)	8.5 (7.1)	7.5 (6.6)	< 0.001 *	< 0.001 *
Days from admission to first high potassium lab	2.6 (4.3)	1.9 (3.8)	1.2 (3.3)	< 0.001 *	< 0.001 *
Days from first high potassium lab to discharge	6.5 (6.0)	6.6 (5.9)	6.3 (5.7)	0.20	0.09
Potassium Lab Values during Inpatient Stay
Number of potassium lab values, mean (SD)	9.1 (11.3)	10.1 (10.9)	10.9 (11.4)	< 0.001 *	< 0.001 *
Patients with ≥2 potassium lab values, n (%)	13,680 (90.7%)	3,965 (95.9%)	2,491 (96.8%)	< 0.001 *	< 0.001 *
Among patients with ≥2 lab values
First potassium lab value, mean (SD)	5.2 (0.1)	5.8 (0.1)	6.7 (0.7)	< 0.001 *	< 0.001 *
Last potassium lab value, mean (SD)	4.3 (0.7)	4.3 (0.7)	4.4 (0.9)	0.85	< 0.001 *
Potassium lab value returned to ≤5.0 mEq/L during the stay, n (%)	12,000 (87.7%)	3,441 (86.8%)	2,041 (81.9%)	< 0.001 *	< 0.001 *
Monitoring during Inpatient Stay, n (%)
Electrocardiogram^b	6,497 (51.9%)	2,272 (67.9%)	1,773 (82.6%)	< 0.001 *	< 0.001 *
Hyperkalemia treatment during Inpatient Stay, n (%)
Any temporizing agent	4,352 (28.9%)	1,904 (46.0%)	1,880 (73.0%)	< 0.001 *	< 0.001 *
Albuterol	947 (6.3%)	523 (12.6%)	810 (31.5%)	< 0.001 *	< 0.001 *
Calcium	2,487 (16.5%)	1,231 (29.8%)	1,452 (56.4%)	< 0.001 *	< 0.001 *
Insulin with glucose	1,220 (8.1%)	839 (20.3%)	1,251 (48.6%)	< 0.001 *	< 0.001 *
Sodium bicarbonate	2,173 (14.4%)	884 (21.4%)	975 (37.9%)	< 0.001 *	< 0.001 *
SPS	1,759 (11.7%)	1,151 (27.8%)	1,167 (45.3%)	< 0.001 *	< 0.001 *
Patiromer	2 (0.0%)	2 (0.0%)	3 (0.1%)	0.20	< 0.05 *
Diuretics	4,930 (32.7%)	1,536 (37.1%)	890 (34.6%)	< 0.001 *	0.06
Dialysis	1,709 (11.3%)	614 (14.8%)	578 (22.5%)	< 0.001 *	< 0.001 *
Hyperkalemia Treatments at Discharge, n (%)
SPS at discharge	10 (0.1%)	6 (0.1%)	10 (0.4%)	0.21	< 0.001 *
Patiromer at discharge	0 (0.0%)	1 (0.0%)	2 (0.1%)	0.22	< 0.05 *
Diuretics at discharge	1,289 (8.5%)	376 (9.1%)	200 (7.8%)	0.28	0.20
Other treatments, n (%)
RAASi during inpatient stay	1,702 (11.3%)	488 (11.8%)	238 (9.2%)	0.37	<0.01 *
RAASi at discharge	860 (5.7%)	256 (6.2%)	126 (4.9%)	0.25	0.11

*p-values <0.05 were considered statistically significant.

^aVariables analyzed between the first potassium lab >5.0mEq/L during stay and the discharge date.

^bECG use was calculated among patients with ECG data available (mild hyperkalemia, n = 12,522; moderate hyperkalemia, n = 3,345; severe hyperkalemia, n = 2,147); p-values for categorical variables were calculated using chi-squared tests; p-values for continuous variables were calculated using analysis of variance tests.

ECG, electrocardiogram; n, number; SD, standard deviation; RAASi, renin-angiotensin-aldosterone system inhibitor; SPS, sodium polystyrene sulfonate

Figure 1. Post-discharge events 30, 60, and 90 days after inpatient stay by hyperkalemia severity

*p-values <0.05 were considered statistically significant.