Table 1.
Baseline and clinical characteristics of the study population according to serum total calcium
| Variable | Total (5.7–19.9) (N = 3,016) | Serum total calcium, mg/dL | P | ||||
|---|---|---|---|---|---|---|---|
| Q1 (≤8.20) (n = 587) | Q2 (8.30–8.60) (n = 590) | Q3 (8.70–8.90) (n = 493) | Q4 (9.00–9.50) (n = 697) | Q5 (≥9.60) (n = 649) | |||
| Baseline variables | |||||||
| Age, y | 65.29 ± 15.19 | 68.34 ± 14.53 | 66.93 ± 14.98 | 67.07 ± 14.61 | 64.22 ± 15.56 | 60.85 ± 14.88 | <0.001 |
| Female | 1,289 (42.74%) | 243 (41.40%) | 245 (41.53%) | 215 (43.61%) | 287 (41.18%) | 299 (46.07%) | 0.333 |
| Ethnicity | <0.001 | ||||||
| White | 2,204 (73.08%) | 446 (75.98%) | 466 (78.98%) | 374 (75.86%) | 492 (70.59%) | 426 (65.64%) | |
| Asian | 89 (2.95%) | 30 (5.11%) | 18 (3.05%) | 9 (1.83%) | 19 (2.73%) | 13 (2.00%) | |
| Black | 297 (9.85%) | 36 (6.13%) | 41 (6.95%) | 55 (11.16%) | 70 (10.04%) | 95 (14.64%) | |
| Hispanic or Latino | 92 (3.05%) | 17 (2.90%) | 14 (2.37%) | 7 (1.42%) | 29 (4.16%) | 25 (3.85%) | |
| Other | 334 (11.07%) | 58 (9.88%) | 51 (8.64%) | 48 (9.74%) | 87 (12.48%) | 90 (13.87%) | |
| BMI, kg/m2 | 29.70 ± 9.74 | 28.13 ± 7.95 | 28.72 ± 7.70 | 30.31 ± 10.41 | 30.76 ± 10.40 | 29.83 ± 8.47 | <0.001 |
| Vital signs | |||||||
| Heart rate, b/min | 92.82 ± 17.45 | 95.33 ± 18.45 | 92.82 ± 17.17 | 91.19 ± 17.11 | 92.05 ± 16.81 | 92.60 ± 17.51 | 0.001 |
| SBP, mm Hg | 109.21 ± 13.56 | 106.27 ± 12.39 | 108.91 ± 13.50 | 109.36 ± 12.05 | 110.62 ± 14.15 | 110.48 ± 14.59 | <0.001 |
| DBP, mm Hg | 57.38 ± 9.44 | 56.21 ± 9.42 | 56.83 ± 8.90 | 57.72 ± 8.67 | 58.54 ± 9.98 | 57.42 ± 9.77 | <0.001 |
| MAP, mm Hg | 72.71 ± 9.41 | 70.85 ± 8.66 | 72.38 ± 9.16 | 72.88 ± 8.65 | 73.79 ± 9.87 | 73.37 ± 10.05 | <0.001 |
| Respiratory rate, b/min | 21.43 ± 4.64 | 21.83 ± 4.86 | 21.56 ± 4.37 | 21.18 ± 4.40 | 21.44 ± 4.64 | 21.13 ± 4.83 | 0.066 |
| Temperature, °C | 36.88 ± 0.79 | 36.81 ± 0.77 | 36.92 ± 0.74 | 36.90 ± 0.82 | 36.91 ± 0.82 | 36.87 ± 0.80 | 0.024 |
| Spo2, % | 96.76 ± 2.94 | 96.36 ± 3.93 | 96.98 ± 2.49 | 96.74 ± 2.45 | 96.87 ± 2.59 | 96.80 ± 2.93 | 0.005 |
| Blood gas analysis | |||||||
| Pco2, mm Hg | 53.90 ± 18.43 | 47.88 ± 15.72 | 50.64 ± 17.24 | 53.99 ± 16.81 | 55.79 ± 19.89 | 59.58 ± 19.02 | <0.001 |
| PO2, mm Hg | 50.00 (38.00–69.00) | 52.00 (40.00–75.00) | 53.00 (39.00–72.00) | 53.50 (38.00–70.00) | 50.00 (38.00–68.00) | 45.00 (35.00–61.00) | <0.001 |
| pH | 7.24 ± 0.13 | 7.25 ± 0.13 | 7.26 ± 0.12 | 7.25 ± 0.12 | 7.25 ± 0.13 | 7.20 ± 0.13 | <0.001 |
| Potassium, mEq/L | 4.72 ± 0.96 | 4.63 ± 0.94 | 4.61 ± 0.87 | 4.76 ± 0.93 | 4.74 ± 1.02 | 4.87 ± 1.01 | <0.001 |
| Sodium, mEq/L | 135.94 ± 6.00 | 136.11 ± 6.21 | 136.20 ± 6.34 | 135.83 ± 5.54 | 135.88 ± 5.77 | 135.68 ± 6.06 | 0.548 |
| Lactate, mmol/L | 2.80 (1.70–4.62) | 3.00 (1.80–5.00) | 2.80 (1.80–4.70) | 2.70 (1.70–4.40) | 2.50 (1.65–4.30) | 2.90 (1.70–5.00) | <0.001 |
| Laboratory parameters | |||||||
| Cr, mg/dL | 1.70 (1.10–2.80) | 1.60 (1.10–2.70) | 1.60 (1.02–2.60) | 1.60 (1.10–2.60) | 1.70 (1.10–2.80) | 2.00 (1.20–3.60) | <0.001 |
| BUN, mg/dL | 35.00 (22.00–55.00) | 35.00 (22.00–54.00) | 35.00 (21.00–55.75) | 32.00 (21.00–50.00) | 34.00 (22.00–54.00) | 36.00 (24.00–61.00) | 0.015 |
| RBC, M/uL | 2.79 ± 0.56 | 2.90 ± 0.55 | 2.88 ± 0.54 | 2.85 ± 0.53 | 2.78 ± 0.53 | 2.57 ± 0.55 | <0.001 |
| Hemoglobin, g/L | 9.54 ± 1.89 | 9.36 ± 1.82 | 9.70 ± 1.86 | 9.63 ± 1.84 | 9.67 ± 1.90 | 9.33 ± 2.00 | <0.001 |
| WBC, K/uL | 15.30 (9.83–22.10) | 15.65 (9.20–23.30) | 15.20 (10.45–22.25) | 15.70 (10.90–22.30) | 15.30 (10.10–21.55) | 14.40 (8.60–21.40) | 0.018 |
| PLT, K/uL | 163.00 (97.00–245.00) | 155.50 (92.00–235.75) | 173.50 (113.75–258.75) | 168.00 (104.00–245.00) | 175.00 (107.00–257.25) | 142.00 (70.00–224.00) | <0.001 |
| APTT, s | 37.30 (30.90–52.30) | 37.60 (31.10–51.00) | 35.45 (29.70–46.40) | 37.10 (31.20–51.00) | 36.30 (30.70–52.40) | 40.10 (31.70–60.20) | <0.001 |
| INR | 1.50 (1.30–2.10) | 1.60 (1.30–2.10) | 1.40 (1.30–1.80) | 1.50 (1.20–2.00) | 1.50 (1.30–2.00) | 1.60 (1.30–2.30) | <0.001 |
| PT, s | 16.30 (14.20–20.45) | 16.60 (14.50–20.70) | 15.80 (14.00–19.10) | 16.05 (13.97–19.70) | 16.10 (14.20–20.20) | 17.00 (14.30–22.90) | 0.023 |
| Alb, g/dL | 2.83 ± 0.56 | 2.64 ± 0.56 | 2.80 ± 0.53 | 2.90 ± 0.520 | 2.92 ± 0.51 | 2.87 ± 0.60 | <0.001 |
| Score system | |||||||
| SOFA | 7.00 (5.00–10.00) | 8.00 (5.00–10.00) | 7.00 (5.00–9.00) | 7.00 (5.00–9.00) | 7.00 (5.00–10.00) | 8.00 (5.00–11.00) | <0.001 |
| LODS | 6.00 (4.00–8.00) | 7.00 (5.00–9.00) | 6.00 (4.00–8.00) | 6.00 (4.00–8.00) | 6.00 (4.00–8.00) | 7.00 (5.00–9.00) | <0.001 |
| SAPSII | 47.33 ± 15.34 | 50.38 ± 16.37 | 46.41 ± 15.36 | 46.22 ± 14.90 | 45.57 ± 14.69 | 48.13 ± 14.97 | <0.001 |
| SIRS | 3.28 ± 0.81 | 3.29 ± 0.79 | 3.35 ± 0.79 | 3.29 ± 0.82 | 3.26 ± 0.80 | 3.22 ± 0.86 | 0.063 |
| Interventions | |||||||
| Ventilation | 701 (56.40%) | 289 (49.23%) | 308 (52.20%) | 284 (57.61%) | 405 (58.11%) | 415 (63.94%) | <0.001 |
| CRRT | 353 (11.70%) | 23 (3.92%) | 20 (3.39%) | 27 (5.48%) | 71 (10.19%) | 212 (32.67%) | <0.001 |
| Vasopressor | 2,233 (74.04%) | 439 (74.79%) | 450 (76.27%) | 352 (71.40%) | 499 (71.59%) | 493 (75.96%) | 0.141 |
| Comorbidity | |||||||
| Congestive heart failure | 1,156 (38.33%) | 188 (32.03%) | 216 (36.61%) | 192 (38.95%) | 297 (42.61%) | 263 (40.52%) | 0.002 |
| Neurological disease | 462 (15.32%) | 82 (13.97%) | 94 (15.93%) | 61 (12.37%) | 111 (15.93%) | 114 (17.57%) | 0.135 |
| COPD | 718 (23.81%) | 111 (18.91%) | 132 (22.37%) | 113 (22.92%) | 210 (30.13%) | 152 (23.42%) | <0.001 |
| Diabetes | 761 (25.23%) | 158 (26.92%) | 129 (21.86%) | 126 (25.56%) | 197 (28.26%) | 151 (23.27%) | 0.057 |
| Renal failure | 723 (23.97%) | 106 (18.06%) | 126 (21.36%) | 115 (23.33%) | 170 (24.39%) | 206 (31.74%) | <0.001 |
| Metastatic cancer | 229 (7.59%) | 86 (14.65%) | 48 (8.14%) | 30 (6.09%) | 29 (4.16%) | 36 (5.55%) | <0.001 |
| 28-Day mortality | 1,075 (35.64%) | 304 (51.79%) | 177 (30.00%) | 150 (30.43%) | 207 (29.70%) | 237 (36.52%) | <0.001 |
Results are expressed as mean ± SD, median (Q1–Q3) or n (%).
Alb, albumin; APTT, partial thromboplastin time; BMI, body mass index; BUN, serum urea nitrogen; COPD, chronic obstructive pulmonary disease; Cr, creatinine; CRRT, continuous renal replacement therapy; DBP, diastolic blood pressure; INR, international normalized ratio; LODS, Logistic Organ Dysfunction System; MAP, mean arterial pressure; Pco2, carbon dioxide; PLT, platelet; PO2, partial pressure of oxygen; PT, prothrombin time; RBC, red blood cell count; SAPSII, Simplified Acute Physiology Score II; SBP, systolic blood pressure; SIRS, systemic inflammatory response syndrome; SOFA, Sequential Organ Failure Assessment; Spo2, oxygen saturation; WBC, white blood cell count.