Characteristic | Group A | Group B | Group C | p (Among 3 groups) | p (Group B vs. Group C) |
---|---|---|---|---|---|
n. (%) | 954 (100) | 771 (100) | 420 (100) | Â | Â |
Demographics | Â | Â | Â | Â | Â |
 Male, n. (%) | 451 (47) | 368 (48) | 186 (44) | 0.492 | 0.255 |
 Age, median (IQR) years | 67 (47–81) | 75 (61–83) | 75 (61–84) | <0.001 | 0.868 |
Comorbidities, n. (%) | Â | Â | Â | Â | Â |
 Congestive heart failure | 148 (16) | 170 (22) | 103 (25) | <0.001 | 0.332 |
 Chronic obstructive pulmonary disease | 139 (15) | 237 (31) | 115 (27) | <0.001 | 0.225 |
 Diabetes mellitus | 111 (12) | 118 (15) | 61 (15) | 0.069 | 0.731 |
 Cerebrovascular disease | 83 (9) | 93 (12) | 70 (17) | <0.001 | 0.027 |
 Chronic renal failure | 63 (7) | 63 (8) | 68 (16) | <0.001 | <0.001 |
 Liver disease | 52 (6) | 27 (4) | 32 (8) | 0.008 | 0.002 |
 Residency in a nursing home | 46 (5) | 63 (8) | 54 (13) | <0.001 | 0.009 |
Severity on admission, n. (%) | Â | Â | Â | Â | Â |
 PSI Risk Class IV and V | 332 (35) | 464 (60) | 343 (82) | <0.001 | <0.001 |
 CURB-65 score 3, 4 and 5 | 127 (13) | 198 (26) | 231 (55) | <0.001 | <0.001 |
 Admission to ICU | 6 (0.6) | 54 (7) | 90 (21) | <0.001 | <0.001 |
Physical findings on admission, median (IQR) | Â | Â | Â | Â | Â |
 Systolic blood pressure, mmHg | 127 (112–145) | 130 (115–150) | 108 (85–133) | <0.001 | <0.001 |
 Diastolic blood pressure, mmHg | 70 (64–80) | 71 (62–80) | 60 (50–72) | <0.001 | <0.001 |
 Heart rate, beats/minute | 95 (83–107) | 100 (85–114) | 110 (100–120) | <0.001 | <0.001 |
 Respiratory rate, breaths/minute | 20 (18–26) | 24 (20–30) | 30 (24–34) | <0.001 | <0.001 |
 SpO2,% | 96 (95–97) | 92 (89–95) | 90 (85–93) | <0.001 | <0.001 |
Laboratory values, median (IQR) | Â | Â | Â | Â | Â |
 Arterial pH | 7.45 (7.42-7.48) | 7.44 (7.40-7.48) | 7.39 (7.31-7.46) | <0.001 | <0.001 |
 PaO2/FiO2 ratio | 339 (318–378) | 256 (216–279) | 229 (182–276) | <0.001 | <0.001 |
 PaCO2, mmHg | 33 (29–38) | 36 (31–42) | 36 (30–48) | <0.001 | 0.164 |
 Respiratory acidosis, n. (%) | 0 (0) | 59 (8) | 47 (13) | <0.001 | 0.014 |
 White blood cells, cell/L−1 | 11900 (8238–16300) | 12790 (9100–17000) | 144000 (9993–19000) | <0.001 | 0.001 |
 Platelet, cell/L−1 | 232000 (182000–300500) | 237000 (186500–317000) | 233000 (166750–307250) | 0.054 | 0.028 |
 Hemoglobin, g/dL | 13 (12–14) | 13 (12–14) | 13 (11–14) | 0.010 | 0.021 |
 Hematocrit,% | 39 (36–42) | 40 (37–44) | 39 (34–43) | <0.001 | 0.001 |
 Urea, mg/dL | 37 (27–54) | 45 (31–64) | 63 (42–103) | <0.001 | <0.001 |
 Creatinine, mg/dL | 0.9 (0.8-1.2) | 1.0 (0.8-1.2) | 1.2 (0.9-1.9) | <0.001 | <0.001 |
 Sodium, mEq/L | 137 (134–139) | 137 (134–139) | 136 (133–140) | 0.650 | 0.409 |
 Glucose, mg/dL | 105 (73–128) | 113 (74–148) | 101 (65–149) | 0.002 | 0.035 |
Radiology findings on CXR, n. (%) | Â | Â | Â | Â | Â |
 Multilobar involvement | 161 (18) | 195 (28) | 141 (36) | <0.001 | 0.003 |
 Pleural effusion | 204 (22) | 150 (20) | 100 (24) | 0.209 | 0.078 |
Microbiological findings, n. (%) | Â | Â | Â | Â | Â |
 Patients with isolated bacteria | 184 (19) | 198 (26) | 141 (34) | <0.001 | 0.004 |
 Polymicrobial infection | 3 (2) | 8 (4) | 4 (3) | 0.369 | 0.547 |
 Patients with > = one MDR pathogen | 17 (4) | 20 (5) | 22 (8) | 0.015 | 0.060 |
 S. pneumoniae | 90 (49) | 114 (58) | 64 (45) | 0.064 | 0.027 |
 S. aureus | 15 (8) | 19 (10) | 23 (16) | 0.049 | 0.064 |
 Legionella pneumophila | 16 (9) | 16 (8) | 5 (4) | 0.156 | 0.088 |
 Respiratory viruses | 11 (6) | 12 (6) | 13 (9) | 0.439 | 0.273 |
 Atypicals | 31 (17) | 22 (11) | 9 (6) | 0.014 | 0.137 |
 H. influenzae | 17 (9) | 14 (7) | 7 (5) | 0.328 | 0.419 |
Empiric antibiotic therapy, n. (%) | Â | Â | Â | Â | Â |
 Levofloxacin | 287 (30) | 234 (30) | 106 (25) | 0.133 |  |
 Ceftriaxone | 348 (37) | 324 (42) | 145 (35) | 0.015 |  |
 Amoxicillin (clavulanate) | 295 (31) | 218 (28) | 148 (35) | 0.045 |  |
 Azithromycin | 230 (24) | 189 (25) | 72 (17) | 0.007 |  |
 Clarithromycin | 198 (21) | 211 (27) | 152 (36) | <0.001 |  |
 Piperacillin/tazobactam | 34 (3.6) | 44 (5.7) | 43 (10) | <0.001 |  |
 Antibiotics compliant with local guidelines | 731 (81) | 595 (79) | 328 (79) | 0.606 | 0.933 |
Outcomes | Â | Â | Â | Â | Â |
 Length of hospital stay, median (IQR) days | 6 (3–11) | 9 (6–14) | 12 (7–21) | <0.001 | 0.004 |
 In-hospital mortality, n. (%) | 43 (4.2) | 72 (9.3) | 108 (26) | <0.001 | <0.001 |