Table 5. Differences among demographic data, underlying diseases, and clinical symptoms and signs between acute Q fever patients whose sera were positive and negative for Mycoplasma pneumoniae IgM^a.

Clinical characteristics	Negative for M. pneumoniae IgM (N=43)	Positive for M. pneumoniae IgM (N=59)	Total (N=102)	p b
Demographic data and underlying diseases
Male gender	40 (93.0)	55(93.2)	95 (93.1)	0.999
Age (years)c	43.6 ± 11.8	44.8 ± 12.0	44.3 ± 11.9	0.602
HBV or HCV infectiond	11 (25.6)	21 (35.6)	32 (31.4)	0.388
Liver cirrhosis	1 (2.3)	0 (0)	1 (1.0)	0.422
Hypertension	4 (9.3)	7 (11.9)	11 (10.8)	0.757
Diabetes mellitus	4 (9.3)	3 (5.1)	7 (6.9)	0.451
Congestive heart failure	0 (0)	1 (1.7)	1 (1.0)	0.999
COPD	0 (0)	1 (1.7)	1 (1.0)	0.999
Malignancy	0 (0)	2 (3.4)	2 (2.0)	0.507
HIV infection	1 (2.3)	0 (0)	1 (1.0)	0.422
Clinical symptoms and signs
Fever	42 (97.7)	59 (100)	101 (99.0)	0.422
Chills	34 (79.1)	50 (84.7)	84 (82.4)	0.600
Headache	35 (81.4)	42 (71.2)	77 (75.5)	0.255
Sore throat	7 (16.3)	5 (8.5)	12 (11.8)	0.351
Jaundice	2 (4.7)	3 (5.1)	5 (4.9)	0.999
Cough	10 (23.3)	21 (35.6)	31 (30.4)	0.199
Nausea or vomiting	2 (4.7)	4 (6.8)	6 (5.9)	0.999
Abdominal pain or discomfort	7 (16.3)	6 (10.2)	13 (12.7)	0.384
Diarrhea	4 (9.3)	5 (8.5)	9 (8.8)	0.999
General weakness	8 (18.6)	5 (8.5)	13 (12.7)	0.145
Arthralgia	1 (2.3)	2 (3.4)	3 (2.9)	0.999
Myalgia	19 (44.2)	18 (30.5)	37 (36.3)	0.211
Relative bradycardiae	16 (37.2)	32 (54.2)	48 (47.1)	0.110

^aTested by ELISA (NovaTec Immundiagnostica GmbH, Germany).

^bCategorical variables were analyzed using the Chi-square or Fisher’s exact test as appropriate. Continuous variables were analyzed using Student’s t-test.

^cPresented as the mean value ± standard deviation.

^dConfirmed by examinations of HBsAg and anti-HCV.

^eBody temperature ≥ 38.9^oC and heart rate < 110/min without medication with calcium blockers, beta-blockers, or anti-arrhythmic agents.