TABLE 1

Clinical characteristics of bacteraemic and nonbacteraemic community-acquired pneumonia (CAP) outpatients, and significant univariate and multivariate logistic regression analyses of predictors for bacteraemia in outpatients

VariableBacteraemic CAPNonbacteraemic CAPp-value
Patients n26346
Demographic
 Age years mean±sd48.7±17.144.7±16.70.19
 Age ≥50 years15 (57.7)123 (35.5)0.024
 Men13 (50.0)196 (56.6)0.51
 Current smokers8 (32.0)132 (38.5)0.52
 Current alcohol consumer4 (16.0)44 (12.9)0.66
Previous antibiotic2 (8.3)87 (26.1)0.052
Influenza vaccine5 (21.7)51 (16.1)0.49
Pneumococcal vaccine0 (0)20 (6.3)0.21
Inhaled corticosteroid1 (3.8)10 (2.9)0.79
Systemic corticosteroid1 (4.3)1 (0.3)0.13
Symptoms
 Cough21 (80.8)268 (78.4)0.77
 Fever26 (96.2)322 (94.4)0.71
 Purulent sputum14 (53.8)180 (53.1)0.94
 Pleuritic pain19 (73.1)177 (52.1)0.038
 Dyspnoea5 (19.2)105 (30.7)0.22
 Altered mental status0 (0)6 (1.7)0.50
Comorbidities#5 (19.2)102 (29.5)0.27
 Chronic respiratory disease1 (3.8)60 (17.6)0.069
 Chronic cardiovascular disease0 (0)8 (2.3)0.43
 Diabetes mellitus2 (7.7)18 (5.2)0.59
 Neurological disease1 (3.8)20 (5.9)0.66
 Chronic renal disease0 (0)0 (0)
 Chronic liver disease1 (3.8)8 (2.3)0.63
Nursing-home0 (0)3 (0.9)>0.99
Laboratory tests median (IQR)
 Creatinine mg·mL−10.9 (0.8–1.1)1 (0.8–1.2)0.36
 C-reactive protein mg·dL−124.2 (15.4–29)13.4 (6.8–21.3)0.001
 White blood cell count ×109 per L16.7 (12.7–23.5)11.5 (7.8–15.7)0.001
CURB-65 risk class 0–122 (91.7)301 (94.1)0.64
PSI risk class I–II23 (88.4)301 (87.0)0.83
Pulmonary complications2 (8.0)32 (9.4)0.82
Acute renal failure1 (4.0)11 (3.3)0.86
Readmission0 (0)0 (0)
30-day mortality0 (0)0 (0)
Appropriate empiric treatment26 (100)346 (100)
UnivariateMultivariate
OR (95% CI)p-valueOR (95% CI)p-value
Age ≥50 years2.47 (1.10–5.55)0.0283.16 (1.19–8.42)0.021
Previous antibiotic0.26 (0.06–1.12)0.070
Pleuritic pain2.50 (1.02–6.10)0.0444.06 (1.39–11.89)0.010
C-reactive protein ≥22.945 mg·dL−1+8.81 (342–22.70)<0.00110.08 (3.74–27.20)<0.001
White blood cell count ≥10×109 per L2.28 (0.89–5.86)0.087
  • Data are presented as n (%) unless otherwise stated. Percentages were calculated using nonmissing data. Exclusion criteria were: 1) unavailable blood culture; 2) severe immunosuppression (AIDS, chemotherapy or immunosuppressive drugs (e.g. oral corticosteroid ≥10 mg prednisone or equivalent per day for ≥2 weeks)); 3) active tuberculosis; and 4) cases with a confirmed alternate diagnosis. Microbial aetiology: Mycoplasma pneumoniae (n=15, 12%); respiratory viruses (n=10, 8%); Legionella pneumophila (n=10, 8%); Coxiella burnetii (n=5, 4%), Chlamydophila pneumoniae (n=5, 4%); and Haemophilus influenzae (n=5, 4%). More than one causative agent was found in nine (7%) patients; Streptococcus pneumoniae was the most prevalent microorganism involved in mixed infections (four (44%) out of nine). Serotypes in 11 bacteraemic cases were: 1 (n=3, 27%); 19A (n=1, 9%); 3 (n=1, 9%); 6A (n=1, 9%); 7F (n=2, 18%); 11A (n=1, 9%); 10A (n=1, 9%); and 13 (n=1, 9%). IQR: interquartile range; CURB-65: confusion, urea >7 mmol·L−1, respiratory rate ≥30 breaths per min, systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg, age ≥65 years; PSI: Pneumonia Severity Index. #: patients could have more than one comorbidity; : Hosmer–Lemeshow goodness-of-fit test, p=0.49; +: optimal cut-off value to predict bacteraemic CAP using receiver operating characteristic curves.