Participants characteristics of included patients stratified by pulmonary infection
| Characteristics | Total | Non-pulmonary infection | Pulmonary infection | P value |
| (n=1780) | (n=1594) | (n=186) | ||
| Gender | 0.082 | |||
| Female | 644 (36.2) | 588 (36.9) | 56 (30.1) | |
| Male | 1136 (63.8) | 1006 (63.1) | 130 (69.9) | |
| Age (years) | 68 (52.00–80.00) | 68.00 (53.00–80.00) | 67.00 (50.00–79.00) | 0.436 |
| Race | <0.001 | |||
| White | 1171 (65.8) | 1076 (67.5) | 95 (51.1) | |
| Black | 115 (6.5) | 102 (6.4) | 13 (7.0) | |
| Other race | 494 (27.8) | 416 (26.1) | 78 (41.9) | |
| Marital status | 0.106 | |||
| Married | 725 (40.7) | 660 (41.4) | 65 (34.9) | |
| Unmarried | 1055 (59.3) | 934 (58.6) | 121 (65.1) | |
| LOS | 2.80 (1.70–5.53) | 2.65 (1.65–4.89) | 6.88 (2.91–12.11) | <0.001 |
| Hospital mortality | 106 (6.0) | 85 (5.3) | 21 (11.3) | 0.002 |
| Vital signs | ||||
| Heart rate (times/min) | 81.14 (70.85–92.74) | 80.64(70.68–91.76) | 87.34 (75.67–96.53) | <0.001 |
| MBP (mm Hg) | 80.55 (74.27–88.04) | 80.55 (74.22–87.81) | 80.76 (75.02–89.02) | 0.243 |
| Breath rate (times/min) | 17.93 (16.21–20.12) | 17.83 (16.16–19.93) | 18.87 (16.88–22.06) | <0.001 |
| Temperature (℃) | 36.95 (36.72–37.28) | 36.93 (36.71–37.23) | 37.13 (36.78–37.60) | <0.001 |
| Severity score | ||||
| GCS | 0.001 | |||
| ≥13 | 1391 (78.1) | 1260 (79) | 130 (69.9) | |
| 9–12 | 259 (14.6) | 229 (14.4) | 31 (16.7) | |
| <9 | 130 (7.3) | 105 (6.6) | 25 (13.4) | |
| SAPSII | 32.00 (25.00–39.00) | 32.00 (25.00–39.00) | 34.00 (27.00–41.75) | 0.006 |
| SOFA | 3.00 (2.00–5.00) | 3.00(2.00–5.00) | 4.00 (2.00–6.00) | <0.001 |
| Laboratory tests | ||||
| SpO2 | 97.55 (96.19–98.75) | 97.51 (96.20–98.69) | 97.98 (96.04–99.25) | 0.092 |
| Glucose (mg/dL) | 127.00 (107.24–150.43) | 126.17 (106.84–149.81) | 131.55 (115.13–152.25) | 0.017 |
| Anion gap (mmol/L) | 16.00 (14.00–18.00) | 16.00 (14.00–18.00) | 16.00 (14.00–18.00) | 0.232 |
| Bicarbonate (mmol/L) | 22.00 (20.00–25.00) | 22.00 (20.00–25.00) | 22.00 (19.00–24.00) | 0.109 |
| Chloride (mmol/L) | 106.00 (102.00–109.00) | 106.00 (102.00–109.00) | 106.00 (102.00–110.00) | 0.229 |
| Haematocrit (μmol/L) | 32.50 (28.00–36.60) | 32.70 (28.20–36.80) | 32.10 (27.22–35.50) | 0.016 |
| Haemoglobin (g/dL) | 10.90 (9.40–12.40) | 11.00 (9.50–12.40) | 10.65 (8.80–11.88) | 0.014 |
| Platelet (K/μL) | 172.50 (131.00–221.00) | 174.00 (134.00–221.00) | 161.50 (114.25–213.00) | 0.033 |
| Potassium (K/μL) | 4.30 (3.90–4.70) | 4.30 (3.90–4.70) | 4.30 (4.00–4.80) | 0.233 |
| PTT (s) | 28.80 (26.40–32.42) | 28.80 (26.40–32.40) | 28.35 (25.75–32.65) | 0.337 |
| INR | 1.20 (1.10–1.40) | 1.20 (1.10–1.40) | 1.20 (1.10–1.40) | 0.011 |
| PT (s) | 13.10 (11.90–14.90) | 13.00 (11.90–14.80) | 13.45 (12.00–15.50) | 0.014 |
| Sodium (mEq/L) | 138.00 (135.00–140.00) | 138.00 (136.00–140.00) | 138.00 (135.00–140.00) | 0.563 |
| BUN (mg/dL) | 17.00 (12.00–24.00) | 17.00 (12.00–24.00) | 19.00 (13.00–25.00) | 0.087 |
| WBC (K/μL) | 11.90 (8.60–15.80) | 11.80 (8.60–15.60) | 14.40 (9.72–17.67) | <0.001 |
| MCH (pg) | 30.40 (29.10–31.80) | 30.40 (29.10–31.78) | 30.65 (29.20–32.00) | 0.344 |
| MCHC (g/L) | 33.10 (32.10–33.90) | 33.10 (32.20–33.90) | 33.00 (32.00–33.90) | 0.473 |
| MCV (fL) | 91.00 (87.00–95.00) | 91.00 (87.00–95.00) | 91.00 (87.00–95.00) | 0.550 |
| RDW | 13.90 (13.20–15.10) | 13.90 (13.20–15.00) | 14.30 (13.33–15.30) | 0.008 |
| Creatinine (mg/dL) | 0.90 (0.80–1.20) | 0.90 (0.72–1.20) | 1.00 (0.80–1.30) | 0.079 |
| Treatment measures | ||||
| Vasopressor | 0.670 | |||
| No | 1700 (95.5) | 1524 (95.6) | 176 (94.6) | |
| Yes | 80 (4.5) | 70 (4.4) | 10 (5.4) | |
| Mechanical ventilation | <0.001 | |||
| No | 1473 (82.8) | 1367 (85.8) | 106 (57.0) | |
| Yes | 307 (17.2) | 227 (14.2) | 80 (43.0) | |
| Antibiotic | <0.001 | |||
| No | 767 (43.1) | 738 (46.3) | 29 (15.6) | |
| Yes | 1013 (56.9) | 856 (53.7) | 157 (84.4) | |
| RRT | 0.214 | |||
| No | 1755 (98.6) | 1574 (98.7) | 181 (97.3) | |
| Yes | 25 (1.4) | 20 (1.3) | 5 (2.7) | |
| Comorbidity | ||||
| AKI | 0.001 | |||
| No | 445 (25.0) | 418 (26.2) | 27 (14.5) | |
| Yes | 1335 (75.0) | 1176 (73.8) | 159 (85.5) | |
| Congestive heart failure | <0.001 | |||
| No | 1541 (86.6) | 1398 (87.7) | 143 (76.9) | |
| Yes | 239 (13.4) | 196 (12.3) | 43 (23.1) | |
| Chronic pulmonary disease | 0.035 | |||
| No | 1539 (86.5) | 1388 (87.1) | 151 (81.2) | |
| Yes | 241 (13.5) | 206 (12.9) | 35 (18.8) | |
| Renal disease | 0.029 | |||
| No | 1558 (87.5) | 1405 (88.1) | 153 (82.3) | |
| Yes | 222 (12.5) | 189 (11.9) | 33 (17.7) | |
| Liver disease | 0.869 | |||
| No | 1656 (93.0) | 1484 (93.1) | 172 (92.5) | |
| Yes | 124 (7.0) | 110 (6.9) | 14 (7.5) |
AKI, acute kidney injury; BUN, blood urea nitrogen; GCS, Glasgow Coma Scale; INR, international normalised ratio; MBP, mean blood pressure; MCH, mean corpuscular haemoglobin; MCHC, mean corpuscular haemoglobin concentration; MCV, mean corpuscular volume; PT, prothrombin time; PTT, partial thromboplastin time; RDW, red cell distribution width; RRT, renal replacement therapy; SAPSII, Simplified Acute Physiology Score II; SOFA, Sequential Organ Failure Assessment; WBC, white blood cell.