Table 1. Baseline characteristics of patients with normal chloride (admission chloride 98–107 mEq/L), hypochloremia (admission chloride <98 mEq/L) and hyperchloremia (admission chloride ≥108 mEq/L).
Data displayed as number (%) for categorical variables and mean ± standard deviation for continuous variables. Groups were compared using ANOVA for continuous variables and chi-square tests for categorical variables.
| Variable | Normal chloride (n = 6436) | Hypochloremia (n = 1384) | Hyperchloremia (n = 1606) | P value |
|---|---|---|---|---|
| Demographics | ||||
| Age | 67.4±15.1 | 67.1±15.2 | 67.8±15.4 | 0.41 |
| Female gender | 2277 (35.4%) | 585 (42.3%) | 657 (40.9%) | <0.001 |
| White race | 5990 (93.1%) | 1248 (90.2%) | 1477 (92.0%) | <0.001 |
| BMI | 29.6±6.9 | 30.3±8.1 | 28.5±6.3 | <0.001 |
| Comorbidities | ||||
| Charlson Comorbidity Index | 2.2±2.5 | 3.5±2.8 | 2.1±2.6 | <0.001 |
| Prior myocardial infarction | 1282 (20.0%) | 278 (20.2%) | 315 (19.6%) | 0.92 |
| Prior heart failure | 1118 (17.4%) | 541 (39.3%) | 200 (12.4%) | <0.001 |
| Prior stroke | 790 (12.3%) | 193 (14.0%) | 181 (11.3%) | 0.07 |
| Prior diabetes mellitus | 1775 (27.6%) | 557 (40.4%) | 366 (22.8%) | <0.001 |
| Prior cancer | 1319 (20.6%) | 349 (25.3%) | 335 (20.9%) | <0.001 |
| Prior lung disease | 1196 (18.6%) | 381 (27.7%) | 240 (14.9%) | <0.001 |
| Prior CKD | 1108 (17.3%) | 516 (37.5%) | 303 (18.9%) | <0.001 |
| Prior dialysis | 254 (4.0%) | 231 (16.7%) | 62 (3.9%) | <0.001 |
| Admission diagnoses | ||||
| Acute coronary syndrome | 2926 (46.0%) | 378 (27.5%) | 723 (45.6%) | <0.001 |
| Heart failure | 2794 (43.9%) | 1035 (75.2%) | 549 (34.6%) | <0.001 |
| Cardiac arrest | 685 (10.8%) | 148 (10.8%) | 276 (17.4%) | <0.001 |
| Shock | 717 (11.3%) | 242 (17.6%) | 298 (18.8%) | <0.001 |
| Cardiogenic shock | 568 (8.9%) | 197 (14.3%) | 233 (14.7%) | <0.001 |
| Sepsis | 345 (5.4%) | 131 (9.5%) | 107 (6.7%) | <0.001 |
| Respiratory failure | 1164 (18.3%) | 420 (30.5%) | 392 (24.7%) | <0.001 |
| Severity of illness | ||||
| APACHE-III score | 59.1±24.1 | 69.8±22.5 | 66.6±29.2 | <0.001 |
| APACHE-IV mortality | 0.154±0.188 | 0.219±0.197 | 0.212±0.242 | <0.001 |
| Day 1 SOFA score | 3.2±3.0 | 4.8±3.3 | 4.3±3.7 | <0.001 |
| Mean week 1 SOFA | 2.7±2.4 | 4.1±2.8 | 3.6±2.1 | <0.001 |
| Acute Kidney Injury | ||||
| Any AKI | 2911 (47.1%) | 882 (76.5%) | 785 (50.8%) | <0.001 |
| No AKI | 3405 (52.9%) | 325 (23.5%) | 790 (49.2%) | <0.001 |
| KDIGO stage 1 | 2153 (33.5%) | 559 (40.4%) | 567 (35.3%) | <0.001 |
| KDIGO stage 2 | 507 (7.9%) | 235 (17.0%) | 131 (8.2%) | <0.001 |
| KDIGO stage 3 | 371 (5.8%) | 264 (19.1%) | 120 (17.5%) | <0.001 |
| Therapies and procedures | ||||
| Invasive ventilator | 902 (14.0%) | 211 (15.2%) | 424 (26.4%) | <0.001 |
| Noninvasive ventilator | 900 (14.0%) | 374 (27.0%) | 192 (12.0%) | <0.001 |
| Vasopressors | 1096 (17.0%) | 413 (29.8%) | 430 (26.8%) | <0.001 |
| Inotropes | 487 (7.6%) | 288 (20.8%) | 100 (6.2%) | <0.001 |
| Coronary angiography | 3580 (55.6%) | 536 (38.7%) | 851 (53.0%) | <0.001 |
| PCI | 2399 (37.3%) | 277 (20.0%) | 608 (37.9%) | <0.001 |
| IABP | 533 (8.3%) | 131 (9.5%) | 169 (10.5%) | 0.01 |
| Pulmonary artery catheter | 419 (6.5%) | 196 (14.2%) | 96 (6.0%) | <0.001 |
| RBC transfusion | 666 (10.4%) | 186 (13.4%) | 296 (18.4%) | <0.001 |
| Dialysis | 223 (3.5%) | 173 (12.5%) | 66 (4.1%) | <0.001 |
| CRRT | 66 (1.0%) | 79 (5.7%) | 22 (1.4%) | <0.001 |
| Admission laboratory data | ||||
| Sodium (mEq/L) | 138.1±3.3 | 132.6±5.4 | 141.0±3.4 | <0.001 |
| Hypernatremia | 774 (12.0%) | 4 (0.3%) | 36 (2.2%) | <0.001 |
| Hyponatremia | 108 (1.7%) | 847 (61.2%) | 193 (12.0%) | <0.001 |
| Potassium (mEq/L) | 4.3±0.6 | 4.4±0.8 | 4.2±0.7 | <0.001 |
| Bicarbonate (mEq/L) | 24.1±3.7 | 26.2±5.7 | 21.3±3.9 | <0.001 |
| Metabolic acidosis | 1382 (21.5%) | 255 (18.4%) | 792 (49.3%) | <0.001 |
| Metabolic alkalosis | 1501 (23.3%) | 625 (45.2%) | 92 (5.7%) | <0.001 |
| Chloride (mEq/L) | 103.0±2.6 | 93.5±3.8 | 110.2±2.7 | <0.001 |
| Anion gap (mEq/L) | 11.0±3.8 | 12.9±4.8 | 9.6±4.2 | <0.001 |
| Elevated anion gap | 1984 (30.8%) | 715 (51.7%) | 323 (20.1%) | <0.001 |
| BUN (mg/dL) | 24.2±15.9 | 39.1±26.5 | 25.4±17.2 | <0.001 |
| Creatinine (mg/dL) | 1.2±0.8 | 2.1±2.0 | 1.2±0.8 | <0.001 |
| Outcomes | ||||
| CICU mortality | 231 (3.6%) | 125 (9.0%) | 133 (8.3%) | <0.001 |
| Hospital mortality | 393 (6.1%) | 227 (16.4%) | 180 (11.2%) | <0.001 |
| CICU LOS | 2.4±4.5 | 3.6±6.9 | 2.5±2.5 | <0.001 |
| Hospital LOS | 7.2±10.4 | 13.2±23.6 | 7.0±10.3 | <0.001 |
AKI = acute kidney injury; APACHE = Acute Physiology and Chronic Health Evaluation; BMI = body mass index; BUN = blood urea nitrogen; CICU = cardiac intensive care unit; CKD = chronic kidney disease; CRRT = continuous renal replacement therapy; IABP = intra-aortic balloon pump; KDIGO = kidney disease improving global outcomes; LOS = length of stay; PCI = percutaneous intervention; RBC = red blood cell; SOFA = sequential organ failure assessment.