Table 1.
Baseline Characteristics of Cases and Controls
| Characteristic | Cases (n = 117) | Controls (n = 48) | P value |
|---|---|---|---|
| Age, y | 69.0 (60.0–78.0) | 70.5 (63.8–75.0) | .911 |
| Sex, male | 64 (54.7) | 28 (58.3) | .799 |
| Ethnicity, Caucasian | 85 (73.3) | 40 (85.1) | .520 |
| Body mass index | 25.29 (6.23) | 27.83 (4.92) | .014 |
| Influenza vaccination | 69 (60.0) | 22 (45.8) | .067 |
| Pneumococcal vaccination | 1 (.9) | 1 (2.1) | .181 |
| Past smoker | 64 (55.2) | 23 (47.9) | .253 |
| Flexitarian diet | 108 (93.9) | 47 (97.9) | .779 |
| Recent exposure to antibioticsa | 11 (9.4) | 2 (4.2) | .182 |
| Chronic comorbidity | |||
| COPD | 36 (30.8) | 4 (8.3) | .004 |
| Cardiovascular disease | 89 (76.1) | 31 (64.6) | .189 |
| Diabetes | 32 (27.4) | 6 (12.5) | .064 |
| Malignancy | 40 (34.2) | 9 (18.8) | .074 |
| Immunosuppressive diseaseb | 30 (25.6) | 4 (8.3) | .022 |
| Gastrointestinal disease | 18 (15.4) | 2 (4.2) | .081 |
| Chronic renal disease | 14 (12.0) | 3 (6.2) | .415 |
| Imaging and microbiology | |||
| Radiologically confirmed CAP | 117 (100.0) | ||
| Blood culture obtained | 109 (93.2) | ||
| Sputum culture obtained | 68 (58.1) | ||
| Viral nasal/throat swab PCR performed | 117 (100.0) | 47 (97.9) | >.999 |
| PUAT/LUAT performed | 73 (62.4) | ||
| Severity of disease and outcome | |||
| PSI class | 4.0 (3.0–4.0) | ||
| ICU admission | 9 (7.8) | ||
| Length of hospital stay, days | 4.0 (3.0, 7.8) | ||
| 28-day mortality | 5 (4.4) |
Data are no. (%) or median (IQR).
Abbreviations: CAP, community-acquired pneumonia; COPD, chronic obstructive pulmonary disease; ICU, intensive care unit; IQR, interquartile range; LUAT, Legionella urinary antigen test; PCR, polymerase chain reaction; PSI, pneumonia severity index; PUAT, pneumococcal urinary antigen test; SD, standard deviation.
aRecent antibiotics usage was defined as antibiotic administration from 90 days up to 48 hours prior to inclusion.
bImmunosuppressive disease was defined as clinically suspected or proven immunodeficiency, the use of immunosuppressive therapy or immunomodulating medication in the past 3 months, including chemotherapy, or the use of more than 10 mg prednisone or equivalent each day for the past 3 months.