TABLE 2

Baseline and clinical characteristics of chronic Q fever cases in the Netherlands

CharacteristicaAll chronic Q fever (n = 284)Proven chronic Q fever (n = 151)Probable chronic Q fever (n = 64)Possible chronic Q fever (n = 69)
Male (n [%])204 (71.6)115 (76)48 (75)41 (59)
Age (mean [SD]) (yr)64.9 (14.1)68.6 (12)65.2 (15)56.6 (15)
Focus of infectionb (n [%])
    Endocarditis75 (26.4)49 (32)26 (41)
        Infection of valve prosthesis38 (13.3)31 (21)7 (11)
    Vascular infection122 (42.0)104 (69)18 (28)
        Infection of vascular prosthesis57 (20.1)45 (30)12 (19)
    Other focus (n [%])6 (2.1)2 (1)i4 (76)l
    No focus (n [%])92 (33.1)7 (5)j16 (25)m69 (100)
Known acute Q fever episode (n [%])106 (37.3)28 (19)k30 (47)48 (70)
    Adequate treatmentc,d81 (76)19 (68)24 (80)38 (79)
    Echocardiogram (TEE or TTE) performedd21 (20)8 (29)3 (10)10 (21)
    Imaging of abdominal aorta by AUSd14 (13)5 (18)4 (13)5 (10)
    Risk factor for chronic Q feverd34 (32)17 (61)15 (50)2 (4)
    Chronic Q fever prophylaxisd,e4 (4)4 (14)
Risk factors for chronic Q fever (n [%])152 (53.5)107 (71)42 (66)3 (4)
    History of valvulopathy68 (23.9)48 (32)19 (30)1 (1)
        Valve prosthesis or plasty45 (15.8)36 (24)9 (14)
    History of aneurysm28 (9.9)22 (15)6 (9)
    History of vascular prosthesis61 (21.5)49 (32)12 (19)
    Immunosuppressionf19 (6.7)11 (7)8 (13)
    Pregnancy during acute episode5 (1.8)1 (1)2 (3)2 (3)
Surgical treatment due to Q fever (n [%])65 (22.9)64 (42)1 (2)
    Valve surgeryg13 (4.6)12 (8)1 (2)
    Vascular surgeryg53 (19.0)54 (36)
Deceasedh (n [%])45 (15.8)35 (23)6 (9)4 (6)
    No. of deceased patients with endocarditis/total no. of patients with endocarditis (%)12/75 (16)10/49 (20)2/24 (8)NAn
    No. of deceased patients with vascular infection/total no. of patients with vascular infection (%)28/122 (23)26/104 (25)2/18 (11)NA
    Definitely or probably deceased due to chronic Q fever (n [%])28 (9.8)27 (18)1 (2)
  • a TEE, transesophageal echocardiography; TTE, transthoracic echocardiography; AUS, abdominal ultrasound.

  • b In 11 proven chronic Q fever patients, imaging studies revealed that the focus of infection could be both on the heart valves and vascular structures.

  • c Proven effective antibiotic treatment regime for at least 10 days.

  • d Percentages estimated for all chronic cases with an acute Q fever episode only.

  • e Doxycycline and hydroxychloroquine for at least 6 months.

  • f Prednisone cumulative dose >750 mg, tumor necrosis factor alpha (TNF-α)-blocker usage, methotrexate usage, mycophenolate mofetil usage, splenectomy, hematologic malignancies.

  • g Two patients underwent both vascular and heart valve surgery, one patient underwent replacement of thoracic aneurysm and aortic valve and one patient underwent replacement of aortic valve and vascular surgery of an aneurysm of the left arteria iliaca.

  • h In two deceased patients with proven chronic Q fever, the focus of infection could have been both on heart valves and vascular structures.

  • i One patient with pericarditis and one patient with an infected placenta (confirmed by PCR).

  • j All had positive PCR results for blood samples; six patients had cardiovascular risk factors, and two were immunocompromised.

  • k Data missing in seven patients.

  • l One patient with pericarditis, two patients with chronic serologic profiles during pregnancy, and one patient with spondylodiscitis.

  • m Six patients with clinical signs of systemic infection, 10 patients with immunocompromised status.

  • n NA, not applicable.