Background
Methods
Setting and Study population
Laboratory assessment
Statistical analysis
Results
Baseline parameters
LegionellaCAP (n = 82) | Non-LegionellaCAP (n = 368) |
P-value
| |
---|---|---|---|
Demographic characteristics | |||
- Age (years)* | 68 (49–77) | 73 (59–82) |
0.01
|
- Sex (male) – no. (%) | 57 (70) | 221 (60) |
0.11
|
Coexisting illnesses – no. (%) | |||
- Congestive heart disease | 20 (24) | 156 (42) |
0.003
|
- Cerebrovascular disease | 7 (9) | 20 (5) |
0.29
|
- Renal dysfunction | 23 (28) | 100 (27) |
0.15
|
- COPDa
| 8 (10) | 90 (24) |
0.004
|
- Neoplastic disease | 17 (21) | 53 (14) |
0.15
|
Clinical History – no. (%) | |||
- Antibiotic pretreatment | 27 (33) | 75 (20) |
0.01
|
- Cough | 55 (70) | 329 (89) |
<0.001
|
- increase in sputum production | 26 (34) | 265 (72) |
<0.001
|
- Dyspnea | 46 (60) | 266 (72) |
0.03
|
Clinical and laboratory findings
| |||
- Confusion – no. (%) | 9 (11) | 31 (8) |
0.4
|
- Respiratory rate (breaths/minute)* | 18 (16–28) | 22 (20–28) |
0.01
|
- Systolic blood pressure (mmHg)* | 130 (113–145) | 130 (113–143) |
0.9
|
- Heart rate (beats/minute)* | 100 (86–114) | 95 (80–110) |
0.05
|
- Body temperature (°C)* | 39.3 (38.5–40.1) | 38.4 (37.6–39.2) |
<0.001
|
Laboratory findings
| |||
- C-reactive protein (mg/L)* | 241 (171–315) | 134 (67–217) |
<0.001
|
- Procalcitonin (μg/L)* | 2.90 (0.93–6.43) | 0.57 (0.19–2.61) |
<0.01
|
- Hematocrit (%)* | 37 (32–41) | 38 (35–40) |
0.17
|
- Leucocyte counts (×109/L)* | 12.9 (9.5–15.5) | 12.8 (8.9–16.8) |
0.47
|
- Platelet counts (×109/L)* | 191 (141–253) | 243 (190–326) |
<0.001
|
- Sodium (mmol/L)* | 132 (128–135) | 136 (133–138) |
<0.001
|
< 131 mmol/L – no. (%) | 36 (46) | 49 (14) |
<0.001
|
- Creatinine (umol/L)* | 101 (80–144) | 105 (83–138) |
0.29
|
- Urea (mmol/L)* | 8.3 (5.4–14.2) | 6.9 (4.9–11.5) |
0.93
|
- Elevated liver enzymesb – no. (%) | 52 (63) | 126 (34) |
<0.001
|
- Creatinine kinase (U/L)* | 103 (48–417) | 77 (41–174) |
<0.01
|
- Lactate dehydrogenase (U/L)* | 252 (204–382) | 214 (175–268) |
<0.001
|
- Glucose (mmol/L)* | 6.9 (6.1–9.7) | 6.8 (5.9–8.4) |
0.12
|
- Oxygen saturation (%)* | 93 (88–95) | 93 (89–96) |
0.46
|
- PaO2 (kPa)* | 7.7 (7.1–9.9) | 8.0 (6.8–9.5) |
0.82
|
- pH* | 7.46 (7.38–7.49) | 7.43 (7.39–7.46) |
0.02
|
- Hemoglobinuria – no. (%) | 45 (70) | 114 (45) |
<0.001
|
- Proteinuria – no. (%) | 46 (73) | 124 (48) |
<0.001
|
Risk assessment
| |||
- PSIc Points* | 117 (90–140) | 95 (73–121) | <0.001 |
- CURB65* | 2 (1–2) | 1 (1–2) | 0.09 |
Outcome – no. (%) | |||
- Death | 13 (16) | 33 (9) | 0.06 |
- Admission to ICUd
| 34 (41) | 43 (12) | 0.01 |
- Length of hospital stay (days)* | 13 (8–20) | 11 (6–17) | 0.02 |
Established by \Etiologic Diagnosis |
L. pn1a
(n = 57) |
L. pn
b& L. spp.c
(n = 13) |
L. spp (n = 12) | |
---|---|---|---|---|
Urinary antigen testing (n = 72) | Positive (n = 59) | 50 | 9 | 0 |
Negative (n = 13) | 1 | 4 | 8 | |
Respiratory specimen culture (n = 54) | Positive (n = 23) | 14 | 8 | 1 |
Negative (n = 31) | 19 | 5 | 7 | |
Respiratory specimen PCRd (n = 38) | Positive (n = 34) | 10 | 13 | 11 |
Negative (n = 4) | 4 | 0 | 0 |
Diagnostic reliability of clinical and laboratory parameters
Univariate analysis | ||||
---|---|---|---|---|
Predictor | Odds ratio | (95% CI*) | P-value | |
Age | 0.98 | 0.97 | 1.00 | 0.017 |
Temperature | 1.93 | 1.51 | 2.46 | <0.0001 |
No dyspnea | 1.75 | 1.06 | 2.9 | 0.03 |
No cough | 3.7 | 2.05 | 6.6 | <0.0001 |
No sputum | 5.14 | 3.04 | 8.7 | <0.0001 |
Sodium | 0.86 | 0.82 | 0.91 | <0.0001 |
Elevated liver enzymes1
| 3.32 | 2.02 | 5.48 | <0.0001 |
Lactate dehydrogenase | 1.003 | 1.002 | 1.005 | 0.001 |
Creatinine kinase | 1.001 | 1.000 | 1.001 | 0.001 |
C-reactive protein (CRP) | 1.006 | 1.004 | 1.008 | <0.0001 |
Platelet counts | 0.993 | 0.990 | 0.996 | <0.0001 |
Hemoglobinuria | 2.95 | 1.64 | 5.32 | <0.0001 |
Proteinuria | 2.88 | 1.56 | 5.29 | 0.001 |
Multivariate analysis
| ||||
Predictor
|
Odds ratio
|
(95% CI)
|
P-value
| |
Temperature | 1.67 | 1.23 | 2.32 | <0.0001 |
No sputum | 3.67 | 1.8 | 7.4 | <0.0001 |
Sodium | 0.89 | 0.84 | 0.96 | 0.01 |
Lactate dehydrogenase | 1.003 | 1.000 | 1.005 | 0.007 |
C-reactive protein (CRP) | 1.006 | 1.003 | 1.009 | <0.0001 |
Platelet counts | 0.991 | 0.987 | 0.995 | <0.0001 |
Parameter | AUC | 95% CI* |
P-value
| Optimal cut off | Sensitivity | Specificity |
---|---|---|---|---|---|---|
Combined Score
| 0.86 | 0.81–0.90 |
-
| < 2 | 78.0 | 78.8 |
Temperature
| 0.74 | 0.63–0.78 |
<0.0001
| > 39.4 | 48.1 | 84.4 |
No sputum
| 0.68 | 0.61–0.74 |
<0.0001
|
-
|
-
|
-
|
Sodium
| 0.71 | 0.63–0.78 |
<0.0001
| < 133 | 64.6 | 70.8 |
Lactate dehydrogenase
| 0.62 | 0.53–0.71 |
<0.0001
| > 225 | 67.1 | 58.1 |
C-reactive protein
| 0.76 | 0.70–0.82 |
<0.0001
| > 187 | 71.6 | 64.7 |
Platelet counts
| 0.71 | 0.64–0.78 |
<0.0001
| < 171 | 45.7 | 83.6 |
Points | Sensitivity | Specificity |
LegionellaCAP | Non-LegionellaCAP |
---|---|---|---|---|
≥ 0 | 100 |
-
| 0 (0%) | 70 (19.0%) |
≥ 1 | 92.7 | 50.3 | 6 (7.3%) | 115 (31.3%) |
≥ 2 | 78.0 | 78.8 | 12 (14.6%) | 105 (28.5%) |
≥ 3 | 58.5 | 93.2 | 16 (19.5%) | 53 (14.4%) |
≥ 4 | 14.6 | 98.9 | 36 (43.9%) | 21 (5.7%) |
≥ 5 | 2.4 | 100 | 10 (12.2%) | 4 (1.1%) |
6 |
-
| 100 | 2 (2.4%) | 0 (0%) |