Table 1.
Covariate Associations with Hyperkalemia and Hypokalemia (N = 321,856)
| N (%) unless otherwise noted | Hyperkalemia | Hypokalemia | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| No N = 320,340; 99.5% | Yes N = 1516; 0.5% | p value* | No N = 319,300; 99.2% | Yes N = 2556; 0.8% | p value* | |||||
| N/mean | %/SD | N/mean | %/SD | N/mean | %/SD | N/mean | %/SD | |||
| Age, mean (SD) | 64.9 | 13.1 | 69.1 | 12.8 | < 0.001 | 64.9 | 13.1 | 65.8 | 13.4 | < 0.001 |
| Male gender | 166,319 | 51.9 | 913 | 60.2 | < 0.001 | 166,216 | 52.1 | 1016 | 39.7 | < 0.001 |
| Race | ||||||||||
| Hispanic | 54,562 | 17.0 | 230 | 15.2 | < 0.001 | 54,474 | 17.1 | 318 | 12.4 | < 0.001 |
| Non-Hispanic White | 173,797 | 54.3 | 920 | 60.7 | 173,340 | 54.3 | 1377 | 53.9 | ||
| Non-Hispanic Black | 28,402 | 8.9 | 110 | 7.3 | 28,061 | 8.8 | 451 | 17.6 | ||
| Other | 55,622 | 17.4 | 231 | 15.2 | 55,479 | 17.4 | 374 | 14.6 | ||
| Unknown | 7957 | 2.5 | 25 | 1.7 | 7946 | 2.5 | 36 | 1.4 | ||
| BMI** | 31.5 | 7.3 | 30.1 | 7.5 | < 0.001 | 31.5 | 7.3 | 31.2 | 7.9 | 0.048 |
| GFR, mean (SD) | 76.6 | 23.4 | 53.4 | 25.7 | < 0.001 | 76.6 | 23.4 | 72.0 | 26.4 | < 0.001 |
| A1c**, mean (SD) | 7.4 | 1.5 | 7.5 | 1.6 | 0.034 | 7.4 | 1.5 | 7.2 | 1.6 | < 0.001 |
| Elixhauser comorbidity score, mean (SD) | 4.0 | 2.7 | 6.1 | 3.5 | < 0.001 | 4.0 | 2.7 | 5.7 | 3.6 | < 0.001 |
| Congestive HF | 28,413 | 8.9 | 334 | 22.0 | < 0.001 | 28,239 | 8.8 | 508 | 19.9 | < 0.001 |
| Malignancy | 17,781 | 5.6 | 142 | 9.4 | < 0.001 | 17,616 | 5.5 | 307 | 12.0 | < 0.001 |
| Hypertension | 218,206 | 68.1 | 1245 | 82.1 | < 0.001 | 217,364 | 68.1 | 2087 | 81.7 | < 0.001 |
| Dementia | 9674 | 3.0 | 111 | 7.3 | < 0.001 | 9624 | 3.0 | 161 | 6.3 | < 0.001 |
| CAD/CVD | 52,680 | 16.4 | 457 | 30.1 | < 0.001 | 52,601 | 16.5 | 536 | 21.0 | < 0.001 |
| Type 1 diabetes | 6246 | 1.9 | 50 | 3.3 | < 0.001 | 6253 | 2.0 | 43 | 1.7 | 0.32 |
| Depression | 48,729 | 15.2 | 290 | 19.1 | < 0.001 | 48,397 | 15.2 | 622 | 24.3 | < 0.001 |
| Proteinuria | < 0.001 | < 0.001 | ||||||||
| Normal | 198,393 | 61.9 | 620 | 40.9 | 197,690 | 61.9 | 1323 | 51.8 | ||
| Macroalbuminuria | 19,255 | 6.0 | 343 | 22.6 | 19,351 | 6.1 | 247 | 9.7 | ||
| Microalbuminuria | 47,871 | 14.9 | 306 | 20.2 | 47,691 | 14.9 | 486 | 19.0 | ||
| Missing | 54,821 | 17.1 | 247 | 16.3 | 54,568 | 17.1 | 500 | 19.6 | ||
| ACE/ARB | 198,777 | 62.1 | 905 | 59.7 | 0.06 | 198,462 | 62.2 | 1220 | 47.7 | < 0.001 |
| Beta blocker | 109,957 | 34.3 | 751 | 49.5 | < 0.001 | 109,634 | 34.3 | 1074 | 42.0 | < 0.001 |
| Digoxin | 5444 | 1.7 | 40 | 2.6 | 0.005 | 5434 | 1.7 | 50 | 2.0 | 0.32 |
| Diuretic, K-sparing | 5586 | 1.7 | 14 | 0.9 | 0.01 | 5449 | 1.7 | 151 | 5.9 | < 0.001 |
| Diuretic, other | 113,165 | 35.3 | 593 | 39.1 | 0.002 | 112,105 | 35.1 | 1653 | 64.7 | < 0.001 |
| Potassium CL supplement | 16,242 | 5.1 | 97 | 6.4 | 0.02 | 15,739 | 4.9 | 600 | 23.5 | < 0.001 |
| Sulfamethoxazole/trimethoprim | 3121 | 1.0 | 40 | 2.6 | < 0.001 | 3119 | 1.0 | 42 | 1.6 | 0.001 |
| 4+ classes BP medications# | 28,858 | 9.0 | 208 | 13.7 | < 0.001 | 28,589 | 9.0 | 477 | 18.7 | < 0.001 |
| Number of medications in prior year, mean (SD) | 9.2 | 5.6 | 11.7 | 6.9 | < 0.001 | 9.2 | 5.6 | 12.3 | 7.2 | < 0.001 |
| Any ED visit in prior year | 88,530 | 27.6 | 709 | 46.8 | < 0.001 | 88,139 | 27.6 | 1100 | 43.0 | < 0.001 |
| Any inpatient stay prior year | 41,732 | 13.0 | 471 | 31.1 | < 0.001 | 41,478 | 13.0 | 725 | 28.4 | < 0.001 |
| Count of K tests prior year, mean (SD) | 1.7 | 2.4 | 3.5 | 4.9 | < 0.001 | 1.7 | 2.4 | 3.5 | 5.3 | < 0.001 |
| Count of K tests 2012–2013, mean (SD) | 3.8 | 3.7 | 6.6 | 7.8 | < 0.001 | 3.8 | 3.7 | 6.2 | 8.4 | < 0.001 |
| 1+ Hyper-K prior year*** | 6141 | 1.9 | 328 | 21.6 | < 0.001 | 6423 | 2.0 | 46 | 1.8 | 0.45 |
| 1+ Hypo-K prior year*** | 6903 | 2.2 | 42 | 2.8 | 0.10 | 6157 | 1.9 | 788 | 30.8 | < 0.001 |
| Any hyper-K or hypo-K in prior 30–365 days | 12,817 | 4.0 | 360 | 23.8 | < 0.001 | 12,366 | 3.9 | 811 | 31.7 | < 0.001 |
| Prior K value, mean (SD)*** | 4.4 | 0.4 | 4.9 | 0.5 | < 0.001 | 4.4 | 0.4 | 3.8 | 0.4 | < 0.001 |
| Missing prior K value | 65,260 | 20.4 | 197 | 13.0 | < 0.001 | 65,078 | 20.4 | 379 | 14.8 | < 0.001 |
*p values from chi-square tests for categorical variables and t tests for continuous variables
#Blood pressure medication classes were as follows: ACE/ARBs, aldosterone antagonists, alpha blockers, alpha-1 adrenergic blockers, alpha-2 adrenergic agonists, beta blockers, CCB-DHP, CCB-nonDHP, thiazide diuretics, direct renin inhibitors, potassium-sparing diuretics, loop diuretics, CAI diuretics, peripheral vasodilators, and reserpine
**Missing data: for BMI n = 1104 (0.3%), A1c n = 12,848 (4.0%)
***Prior hyper-K, hypo-K, and prior K value all examined in the previous 30–365 days. No prior K value was available for n = 65,457 (20.3%)