Table 1.
Demographic, clinical, radiological, and laboratory findings at admission according to the development of respiratory failure
| Variable | Total (n = 521) | Respiratory failure (n = 181) | Non-respiratory failure (n = 340) | p value |
|---|---|---|---|---|
| Baseline characteristics | ||||
| Age (years) | 64.66 ± 18.2 | 71.73 ± 14.91 | 60.89 ± 18.69 | < 0.0001 |
| Gender (male) | 299 (57.6) | 125 (69.1) | 174 (51.5) | < 0.0001 |
| Charlson comorbidity index score | 1 (0–2) | 1 (0–2) | 0 (0–1) | < 0.0001 |
| Hispanic ethnicity (vs. others) | 98 (19.3) | 31 (17.3) | 67 (20.3) | 0.41 |
| Caucasic (vs. others) | 391 (76.8) | 145 (81) | 246 (74.5) | 0.099 |
| Nursing-home or extended-care facility | 17 (3.3) | 11 (6.1) | 6 (1.8) | 0.008 |
| Smoker (current or former) | 131 (25.7) | 64 (35.8) | 67 (20.3) | < 0.0001 |
| Obesity | 150 (34.2) | 61 (38.1) | 89 (32) | 0.19 |
| Diabetes mellitus | 95 (18.3) | 43 (23.8) | 52 (15.3) | 0.018 |
| Hypertension | 217 (42.1) | 97 (54.2) | 120 (35.7) | < 0.0001 |
| Coronary heart disease | 40 (7.7) | 19 (10.5) | 21 (6.2) | 0.078 |
| Congestive heart failure | 33 (6.3) | 16 (8.8) | 17 (5) | 0.087 |
| Peripheral artery disease | 21 (4) | 12 (6.6) | 9 (2.6) | 0.028 |
| Asthma | 40 (7.7) | 6 (3.3) | 34 (10) | 0.006 |
| Chronic obstructive pulmonary disease | 41 (7.9) | 26 (14.4) | 15 (4.4) | < 0.0001 |
| Pulmonary hypertension | 16 (3.2) | 11 (6.3) | 5 (1.5) | 0.004 |
| Sleep apnea syndrome | 37 (7.1) | 21 (11.6) | 16 (4.7) | 0.004 |
| Cerebrovascular disease | 31 (6) | 20 (11) | 11 (3.2) | < 0.0001 |
| Dementia | 53 (10.2) | 30 (16.6) | 23 (6.8) | < 0.0001 |
| Chronic kidney disease | 35 (6.7) | 18 (9.9) | 17 (5) | 0.032 |
| Chronic liver disease | 25 (4.8) | 12 (6.7) | 13 (3.8) | 0.14 |
| Malignancya | 72 (14.3) | 38 (21.8) | 34 (10.3) | < 0.0001 |
| Previous use of steroidsb | 34 (6.6) | 18 (9.9) | 16 (4.7) | 0.023 |
| Clinical findings at admission | ||||
| Duration of illness prior to confirming the infection (days) | 5 (3–7) | 5 (3–7) | 5 (3–7) | 0.68 |
| > 7 days | 116 (22.5) | 36 (20.2) | 80 (23.7) | 0.36 |
| Temperature (ºC) | 37.73 ± 0.97 | 37.63 ± 0.97 | 37.7 ± 0.96 | 0.38 |
| Systolic BP (mm Hg) | 124 (114–138) | 125 (114–140) | 124 (114–138) | 0.72 |
| Heart rate (beats per minute) | 90 (79–103) | 90.5 (78–102) | 90 (80–104) | 0.34 |
| Respiratory rate (breaths per minute) | 18 (15–22) | 20 (16–26.2) | 18 (15–18) | < 0.0001 |
| > 20 breaths per minute | 138 (27.8) | 80 (47.1) | 58 (17.7) | < 0.0001 |
| Altered consciousness | 53 (10.2) | 34 (18.8) | 19 (5.6) | < 0.0001 |
| Dyspnea | 278 (53.5) | 126 (69.6) | 152 (44.8) | < 0.0001 |
| Radiological findings | ||||
| Abnormal Chest X-ray | 416 (81.1) | 158 (87.8) | 258 (77.5) | 0.004 |
| PaO2 (mmHg)c | 67 (55–86.25) | 57 (50.5–70.5) | 79 (62–96) | < 0.0001 |
| SpO2 (%)c | 92.95 ± 6.55 | 88.72 ± 8.56 | 95.22 ± 3.46 | < 0.0001 |
| ePAFI ratio | 376 (282–457) | 285 (241–376) | 409.5 (333–471) | < 0.0001 |
| Leukocytes (× 103 cells/µl) | 5.6 (4.4–7.59) | 6.4 (4.7–8.75) | 5.4 (4.3–7.1) | < 0.0001 |
| Neutrophils (× 103 cells/µl) | 4 (2.9–5.8) | 5 (3.5–7.35) | 3.6 (2.7–5.2) | < 0.0001 |
| Lymphocytes (× 103 cells/µl) | 0.9 (0.6–1.2) | 0.7 (0.5–1) | 1 (0.7–1.3) | < 0.0001 |
| Monocytes (× 103 cells/µl) | 0.5 (0.3–0.7) | 0.4 (0.3–0.7) | 0.5 (0.4–0.7) | 0.013 |
| Platelets (× 103 /µl) | 182 (145.2–233) | 169 (131.5–213.5) | 187 (153–238) | 0.007 |
| Hemoglobin (g/dl) | 13.84 ± 1.88 | 13.57 ± 1.99 | 13.98 ± 1.8 | 0.018 |
| Lactate (mmol/l) | 1.4 (1–1.8) | 1.45 (1.1–2) | 1.2 (1–1.6) | 0.004 |
| Creatinine (mg/dl) | 0.9 (0.71–1.12) | 0.99 (0.8–1.4) | 0.84 (0.69–1.06) | < 0.0001 |
| Triglyceride levels (mg/dl) | 120 (96–159) | 123 (94–160.5) | 120 (97–159) | 0.9 |
| Ferritin levels (ng/ml) | 702 (338–1352) | 1107 (514–2045) | 603 (294–1069) | < 0.0001 |
| LDH (U/l) | 328 (265–413) | 406 (311–527) | 304 (250–368) | < 0.0001 |
| AST (mg/dl) | 33 (24.5–50.8) | 41 (28–58) | 31 (23.2–44.7) | < 0.0001 |
| Albumin (mg/dl) | 3.77 (3.4–4.1) | 3.6 (3.2–3.9) | 3.9 (3.5–4.2) | < 0.0001 |
| Bilirubin (mg/dl) | 0.4 (0.3–0.6) | 0.5 (0.3–0.6) | 0.4 (0.3–0.5) | < 0.0001 |
| Creatine kinase (U/l) | 90 (52–189) | 120 (74–251.5) | 78 (46.7–149.7) | < 0.0001 |
| Troponin T (pg/ml) | 10.3 (5.73–21.4) | 17.5 (9.8–30.7) | 8.1 (5.1–16.25) | < 0.0001 |
| CRP (mg/dl) | 7.62 (3.1–15) | 13.8 (7.33–23.37) | 4.56 (1.83–10.56) | < 0.0001 |
| Procalcitonin (ng/mL) | 0.12 (0.07–0.3) | 0.25 (0.14–0.7) | 0.08 (0.06–0.14) | < 0.0001 |
| Fibrinogen levels (mg/dl) | 669 (581–785) | 723 (622–817.5) | 652 (560–747.5) | < 0.0001 |
| D-dimer (mg/mL) | 611 (373–1091) | 874 (569–1379) | 532 (326–853) | < 0.0001 |
Bold characters indicate p values < 0.05
Data are presented as No. (%) or median (interquartile range) or mean ± standard deviation. Bold characters indicate p values < 0.05. All categorical variables analyzed are dichotomous. The reference category is the absent of the analyzed factor. All laboratory values were available in > 90% of cases except: PaO2 (n = 262); Lactate (n = 229); Triglyceride levels (n = 201); Creatine kinase (n = 415); Troponin T (n = 285); Procalcitonin (n = 163); Fibrinogen levels (n = 346); D-dimer (n = 230)
BP blood pressure; PaO2 partial pressure of oxygen; SpO2 peripheral pulse oximetry; ePAFI estimated pulse oximetry saturation/fraction of inspired oxygen (SpO2/FiO2) ratio; LDH lactate dehydrogenase; AST aspartate aminotransferase; CRP C-reactive protein
aMalignancy includes hematological malignancies and solid organ tumor
bUse of steroids was defined as (1) more than 20 mg/day of oral prednisone during 7 days or longer or (2) less than 20 mg/day during a minimum of 3 months
cMeasured on room air