Baseline demographics of smokers and never smokers
| Smokers n=336 | Never smokers n=837 | P value | |
| Age, years—median (IQR) | 64 (54–73) | 62 (52–73) | 0.30 |
| Sex—no (%) | |||
| Female | 87 (26%) | 366 (44%) | <0.001 |
| Male | 249 (74%) | 471 (56%) | |
| Ethnicity—no (%) | |||
| Hispanic | 183 (54%) | 548 (66%) | <0.001 |
| Black | 114 (34%) | 206 (25%) | |
| Caucasian | 10 (3%) | 6 (1%) | |
| Others | 29 (9%) | 77 (9%) | |
| BMI—median (IQR)* | 28.6 (24.4–33.1) | 28.9 (25.8–33.7) | 0.69 |
| Comorbidities—no (%) | |||
| Hypertension | 213 (63.4%) | 524 (63%) | 0.82 |
| Diabetes mellitus | 158 (47%) | 377 (45%) | 0.68 |
| HIV infection/AIDS | 37 (11%) | 39 (5%) | <0.001 |
| Asthma | 52 (16%) | 111 (13%) | 0.62 |
| COPD | 64 (19%) | 49 (6%) | <0.001 |
| Chronic liver disease | 5 (1.5%) | 6 (1%) | 0.38 |
| Any cancer | 36 (11%) | 50 (6%) | 0.005 |
| Congestive heart failure | 50 (15%) | 66 (8%) | <0.001 |
| Coronary artery disease | 49 (15%) | 78 (9%) | 0.03 |
| Chronic kidney disease | 38 (11%) | 63 (8%) | 0.04 |
| End-stage renal disease | 35 (10%) | 64 (6%) | 0.009 |
| Initial laboratory tests—median (IQR)* | |||
| Absolute neutrophil count (ANC) (k/μL) | 5.7 (3.7–8) | 6.0 (4.1–8.3) | 0.26 |
| Absolute lymphocyte count (ALC) (k/μL) | 0.8 (0.5–1.3) | 0.9 (0.6–1.2) | 0.69 |
| ANC/ALC ratio | 6.6 (4.0–11.6) | 6.8 (4.3–11.4) | 0.49 |
| D-dimer (ng/mL) | 536 (317–1025) | 533 (304–1254) | 0.95 |
| Lactate dehydrogenase (μ/L) | 490 (308–741) | 483(350–690) | 0.63 |
| C-reactive protein (mg/L) | 104.3 (46.6–181.4) | 117.65 (62.42–198.70) | 0.23 |
| Ferritin (ng/mL) | 752.6 (328.8–1466.5) | 700.1 (364.6–1380.5) | 0.40 |
| Lactate (mmoles/L) | 1.8 (1.3–2.55) | 1.8 (1.3–2.5) | 0.40 |
| Creatinine (mg/dL) | 1.2 (0.9–2.07) | 1.0 (0.8–1.6) | <0.001 |
| Alanine aminotransferase (unit/L) | 29 (18–49) | 29 (18–48) | 0.99 |
| Aspartate aminotransferase (unit/L) | 49 (30–78) | 46 (31–71.5) | 0.056 |
| Total protein (g/dL) | 6.9 (6.5–7.6) | 7.0 (6.5–7.5) | 0.67 |
| Serum albumin (g/dL) | 3.6 (3.2–4) | 3.6 (3.3–3.9) | 0.68 |
| Haemoglobin (g/dL) | 13.2 (11.7–14.6) | 13.2 (11.8–14.5) | 0.89 |
| White blood cell (k/μL) | 7.3 (5.3–9.8) | 7.5 (5.5–10.2) | 0.32 |
| Mean corpuscular volume (fL) | 89.15 (84.9–93.1) | 88 (83.7–91.7) | 0.008 |
| Mean corpuscular haemoglobin (pg) | 33.4 (32.6–34.0) | 33.3 (32.5–34.0) | 0.24 |
| Serum sodium (mEq/L) | 136 (133–139) | 137 (133–139) | 0.38 |
| Serum potassium (mEq/L) | 4.5 (4.1–5.0) | 4.4 (4.0–4.9) | 0.15 |
| Chest X-ray (CXR) | |||
| Normal | 46 (14%) | 96 (11%) | 0.25 |
| Alveolar/interstitial infiltrates | 281 (85%) | 727 (88%) | |
| Pleural effusion | 5 (1%) | 6 (1%) | |
| CT chest | |||
| Normal | 0 | 3 (2%) | 0.19 |
| Alveolar/interstitial infiltrates | 52 (96%) | 133 (97%) | |
| Pleural effusion | 2 (4%) | 1 (1%) |
ALC, Absolute lymphocyte count; ANC, Absolute neutrophil count; BMI, body mass index; COPD, chronic obstructive pulmonary disease; CT, Computed tomography; HIV, Human immunodeficiency virus; IQR, Interquartile range.