Variables | Known cause* | Unknown cause* | OR (95% CI) | P value† | |
Age group | ≥65 years | 53 (81.5%) | 12 (18.5%) | 0.73 (0.32 to 1.66) | 0.451 |
<65 years | 58 (76.3%) | 18 (23.7%) | 1.00 | ||
Sex | Male | 48 (76.2%) | 15 (23.8%) | 1.31 (0.59 to 2.95) | 0.510 |
Female | 63 (80.8%) | 15 (19.2%) | 1.00 | ||
Comorbidity | Yes | 69 (78.4%) | 19 (21.6%) | 1.03 (0.44 to 2.37) | 0.951 |
No | 41 (78.8%) | 11 (21.2%) | 1.00 | ||
Symptoms | |||||
Headache | Yes | 17 (73.9%) | 6 (26.1%) | 1.35 (0.48 to 3.80) | 0.566 |
No | 92 (79.3%) | 24 (20.7%) | 1.00 | ||
Chest pain | Yes | 2 (66.7%) | 1 (33.3%) | 1.85 (0.16 to 20.07) | 0.622 |
No | 107 (78.7%) | 29 (21.3%) | 1.00 | ||
Respiratory symptoms | Yes | 19 (79.2%) | 5 (20.8%) | 1.01 (0.34 to 2.98) | 0.987 |
No | 92 (79.3%) | 24 (20.7%) | 1.00 | ||
Gastrointestinal symptoms | Yes | 14 (66.7%) | 7 (33.3%) | 2.09 (0.76 to 5.76) | 0.155 |
No | 96 (80.7%) | 23 (19.3%) | 1.00 | ||
Stomach ache | Yes | 12 (85.7%) | 2 (14.3%) | 0.58 (0.12 to 2.73) | 0.489 |
No | 97 (77.6%) | 28 (22.4%) | 1.00 | ||
Arthralgia | Yes | 38 (86.4%) | 6 (13.6%) | 0.47 (0.18 to 1.24) | 0.127 |
No | 71 (74.7%) | 24 (25.3%) | 1.00 | ||
Muscle pain | Yes | 15 (78.9%) | 4 (21.1%) | 0.95 (0.29 to 3.12) | 0.938 |
No | 93 (78.2%) | 26 (21.8%) | 1.00 | ||
Lymph node enlargement | Yes | 13 (86.7%) | 2 (13.3%) | 0.53 (0.11 to 2.50) | 0.425 |
No | 97 (77.6%) | 28 (22.4%) | 1.00 | ||
Rash | Yes | 26 (81.3%) | 6 (18.8%) | 0.82 (0.30 to 2.21) | 0.692 |
No | 85 (78.0%) | 24 (22.0%) | 1.00 | ||
Ancillary findings | |||||
WBC | Yes | 111 (78.7%) | 30 (21.3%) | NA | NA |
No | 0 (0%) | 0 (0%) | |||
CRP | Yes | 111 (78.7%) | 30 (21.3%) | NA | NA |
No | 0 (0%) | 0 (0%) | |||
ESR | Yes | 86 (74.8%) | 29 (25.2%) | 8.43 (1.09 to 65.00) | 0.041 |
No | 25 (96.2%) | 1 (3.8%) | 1.00 | ||
Procalcitonin | Yes | 41 (75.9%) | 13 (24.1%) | 1.31 (0.58 to 2.96) | 0.523 |
No | 70 (80.5%) | 17 (19.5%) | 1.00 | ||
Blood culture | Yes | 96 (76.8%) | 29 (23.2%) | 4.53 (0.57 to 35.78) | 0.152 |
No | 15 (93.8%) | 1 (6.3%) | 1.00 | ||
Autopsy | Yes | 4 (66.7%) | 2 (33.3%) | 1.88 (0.33 to 10.77) | 0.481 |
No | 105 (78.9%) | 28 (21.1%) | 1.00 | ||
PET | Yes | 33 (75.0%) | 11 (25.0%) | 1.37 (0.59 to 3.19) | 0.468 |
No | 78 (80.4%) | 19 (19.6%) | 1.00 | ||
Ga scintigraphy | Yes | 29 (72.5%) | 11 (27.5%) | 1.64 (0.70 to 3.85) | 0.258 |
No | 82 (81.2%) | 19 (18.8%) | 1.00 |
Stomach ache is different from gastrointestinal symptoms, which include vomiting and diarrhoea.
*Percentage was calculated as the number of patients who received an examination divided by the total patients for each condition.
†χ² tests were performed.
CRP, C reactive protein; ESR, erythrocyte sedimentation rate; Ga, gallium; PET, positron emission tomography; WBC, white blood cell count.