Table 1.
Characteristics of hospitalized patients with hyper- or normonatremia
| Patient Characteristics | All Cohort, N=1,963,020 (100%) | Normonatremia, N=1,902,406 (97%) | Hypernatremia, N=60,614 (3%) | Standardized Mean Difference |
|---|---|---|---|---|
| Age, yr | 58.2 (±19.2) | 57.9 (±19.2) | 65.5 (±18.7) | 0.4 |
| BMI, kg/m2 | 29.6 (±8.1) | 29.6 (±8.1) | 27.8 (±8.1) | 0.23 |
| Systolic BP, mm Hg | 137.8 (±26) | 137.8 (±25.9) | 136.7 (±29.7) | 0.04 |
| Diastolic BP, mm Hg | 78 (±15.8) | 78 (±15.8) | 76.6 (±17.6) | 0.08 |
| eGFR, ml/min per 1.73 m2 | 81.2 (±30.2) | 81.7 (±30) | 65.9 (±32.2) | 0.51 |
| eGFR, ml/min per 1.73 m2 | 0.51 | |||
| <15 | 40,865 (2) | 37,957 (2) | 2908 (5) | |
| 15–29 | 76,993 (4) | 70,607 (4) | 6386 (11) | |
| 30–59 | 359,665 (18) | 341,726 (18) | 17,939 (30) | |
| 60–89 | 668,029 (34) | 649,686 (34) | 18,343 (30) | |
| ≥90 | 817,468 (42) | 802,430 (42) | 15,038 (25) | |
| Sex | ||||
| Women | 1,036,709 (53) | 1,005,506 (53) | 31,203 (52) | 0.03 |
| Race | 0.17 | |||
| White | 1,508,639 (77) | 1,465,674 (77) | 42,965 (71) | |
| Black | 283,213 (14) | 271,349 (14) | 11,864 (20) | |
| Native American | 18,502 (0.9) | 17,412 (0.9) | 1090 (2) | |
| Asian | 31,399 (2) | 30,342 (2) | 1057 (2) | |
| Hispanic | 35202 (2) | 34,173 (2) | 1029 (2) | |
| Pacific Islander | 3277 (0.2) | 3232 (0.2) | 45 (0.1) | |
| Other | 82,788 (4) | 80,224 (4) | 2564 (4) | |
| Quan-CCI categories | 0.29 | |||
| 0 | 716,464 (37) | 699,932 (37) | 16,532 (27) | |
| 1–2 (mild) | 477,687 (24) | 462,726 (24) | 14,961 (25) | |
| 3–4 (moderate) | 219,075 (11) | 209,590 (11) | 9485 (16) | |
| ≥5 (severe) | 196,545 (10) | 186,407 (10) | 10,138 (17) | |
| Unknown | 353,249 (18) | 343,751 (18) | 9498 (16) | |
| Quan-CCI | 1.8 (±2.3) | 1.7±2.3 | 2.4±2.7 | 0.28 |
| Comorbidities | ||||
| Hypertension | 648,371 (33) | 627,375 (33) | 20,996 (35) | 0.07 |
| Heart failure | 167,581 (9) | 158,554 (8) | 9027 (15) | 0.22 |
| Diabetes mellitus | 336,193 (17) | 321,721 (17) | 14,472 (24) | 0.18 |
| Peripheral vascular disease | 50,629 (3) | 48,794 (3) | 1835 (3) | 0.03 |
| Ischemic heart disease | 339,847 (17) | 326,996 (17) | 12,851 (21) | 0.1 |
| CKD | 113,837 (6) | 107,513 (6) | 6324 (10) | 0.19 |
| ESKD | 21,559 (1) | 20,763 (1) | 796 (1) | 0.02 |
| COPD | 275,385 (14) | 265,806 (14) | 9579 (16) | 0.04 |
| Adrenal hyperactivity | 750 (0) | 704 (0) | 46 (0.1) | 0.02 |
| Hyperthyroidism | 6475 (0.3) | 6219 (0.3) | 256 (0.4) | 0.02 |
| Hypothyroidism | 110,031 (6) | 106,415 (6) | 3616 (6) | 0.01 |
| Liver disease | 52,958 (3) | 50,561 (3) | 2397 (4) | 0.07 |
| Depression | 156,180 (8) | 150,750 (8) | 5430 (9) | 0.03 |
| Dementia | 29,178 (2) | 26,180 (1) | 2998 (5) | 0.22 |
| Hypercoagulopathy | 5226 (0.3) | 5108 (0.3) | 118 (0.2) | 0.02 |
| Leading diagnosis | ||||
| Head trauma | 30,341 (2) | 28,591 (2) | 1750 (3) | 0.1 |
| Ischemic stroke | 50,237 (3) | 48,243 (3) | 1994 (3) | 0.04 |
| Hemorrhagic stroke | 8872 (0.5) | 8,293 (0.4) | 579 (1) | 0.07 |
| Obstetrics/gynecologic conditions | 59,733 (3) | 59,528 (3) | 205 (0.3) | 0.24 |
| Pneumonia | 113,544 (6) | 107,142 (6) | 6402 (11) | 0.19 |
| Sepsis | 76,692 (4) | 70,196 (4) | 6496 (11) | 0.3 |
| Central diabetes insipidus | 716 (0) | 568 (0) | 148 (0.2) | 0.06 |
| Nephrogenic diabetes insipidus | 120 (0) | 81 (0) | 39 (0.1) | 0.04 |
| Urinary tract infection | 117,440 (6) | 109,994 (6) | 7446 (12) | 0.24 |
| Laboratory tests | ||||
| Serum albumin, g/dl | 3.8 (±0.6) | 3.7 (±0.6) | 3.6 (±0.7) | 0.24 |
| Serum creatinine, mg/dl | 1.1 (±1) | 1.1 (±1) | 1.4 (±1.2) | 0.28 |
| Serum potassium, mEq/L | 4 (±0.6) | 4 (±0.5) | 4.1 (±0.7) | 0.08 |
| Glucose, mg/dl | 134.8 (±73.3) | 133.5 (±70.5) | 172.7 (±124.4) | 0.39 |
| Hemoglobin A1C | 7 (±2.1) | 7 (±2.1) | 7.4 (±2.4) | 0.15 |
| CO2, meq/L | 25.3 (±3.9) | 25.3 (±3.8) | 24.8 (±5.7) | 0.12 |
| O2 saturation, % | 96.3 (±6.3) | 96.3 (±6.2) | 95.5 (±8) | 0.11 |
| Calcium, mg/dl | 9.1 (±0.6) | 9.1 (±0.6) | 9.1 (±0.9) | 0.06 |
| Phosphorus, mg/dl | 3.5 (±1.2) | 3.5 (±1.1) | 3.8 (±1.7) | 0.2 |
| Magnesium, mmol/L | 2 (±0.4) | 2 (±0.4) | 2.1 (±0.5) | 0.29 |
| Chloride, mmol/L | 103.6 (±4.3) | 103.5 (±4.1) | 108.2 (±5.9) | 0.93 |
| Serum osmolality, mOsm/L | 299 (±27.5) | 295.8 (±24.9) | 326.9 (±32.3) | 1.08 |
| Anion gap, mmol/L | 10.8 (±4.1) | 10.7 (±4) | 13.6 (±5.6) | 0.61 |
| Intact PTH, pg/ml | 195.8 (±299.7) | 195.8 (±299.4) | 196.6 (±305.5) | 0.003 |
| Ferritin, ng/ml | 228.5 (±359.6) | 226.1 (±357.5) | 293.4 (±404.8) | 0.18 |
| Iron saturation, % | 21.9 (±22.3) | 21.9 (±22.3) | 21.8 (±20.9) | 0.003 |
| Hemoglobin, g/dl | 13 (±2.2) | 13 (±2.2) | 12.8 (±2.5) | 0.09 |
| WBC, >103/ml | 10 (±4.7) | 10 (±4.6) | 11.2 (±6) | 0.22 |
| Platelet count | 233.4 (±83.8) | 233.7 (±83.5) | 225.9 (±92.4) | 0.09 |
| Serum uric acid, mmol/L | 96.6 (±37.1) | 95.9 (±36.3) | 115.3 (±49.5) | 0.45 |
| BUN, mmol/L | 18.8 (±13.7) | 18.5 (±13.2) | 28.7 (±22.7) | 0.55 |
| AST, IU/L | 43 (±94.3) | 42.4 (±92.2) | 62.7 (±142.7) | 0.17 |
| ALT, IU/L | 39.7 (±81.8) | 39.3 (±80.8) | 50 (±107.6) | 0.11 |
| Total bilirubin, μmol/L | 0.7 (±0.9) | 0.7 (±0.9) | 0.7 (±0.8) | 0.04 |
| Serum total protein, mg/dl | 6.9 (±0.8) | 6.9 (±0.8) | 6.8 (±1) | 0.12 |
Data shown as mean (±SD) or n (%). Normonatremia: serum sodium (Na) 135–145 mEq/L; hypernatremia: Na>145 mEq/L. Na levels corrected by adding 1.6 mEq/L for each 100 mg/dL above 100 mg/dL of the concomitantly measured serum glucose levels. BMI, body mass index; Quan-CCI, Quan-Charlson comorbidity index; COPD, chronic obstructive pulmonary disease; PTH, parathyroid hormone; WBC, white blood cell; AST, aspartate aminotransferase; ALT, alanine aminotransferase.