Should Acute Q-Fever Patients be Screened for Valvulopathy to Prevent Endocarditis?

Background: Echocardiographic screening of acute Q-fever patients and antibiotic prophylaxis for patients with cardiac valvulopathy is considered an important approach to prevent chronic Q-fever-related endocarditis. During a large Q-fever epidemic in the Netherlands, routine screening echocardiography was discontinued, raising controversy in the international literature. We followed a cohort of acute Q-fever patients to estimate the risk for developing chronic Q-fever, and we evaluated the impact of screening in patients who were not yet known to have a valvulopathy.

Methods: The study population consisted of patients diagnosed with acute Q-fever in 2007 and 2008. We retrospectively reviewed all screening echocardiographs and checked for development of chronic Q-fever 8 years after the acute episode. Risks of developing chronic Q-fever in relation to the presence or absence of valvulopathy were analyzed with logistic regression.

Results: The cohort included 509 patients, of whom 306 received echocardiographic screening. There was no significant difference (P-value = .22) in occurrence of chronic Q-fever between patients with a newly detected valvulopathy (2/84, 2.4%) and those with no valvulopathy (12/202, 5.9%). Two patients with a newly detected valvulopathy, who did not receive antibiotic prophylaxis, developed chronic Q-fever at a later stage.

Conclusions: We found no difference in outcome between patients with and without a valvulopathy newly detected by echocardiographic screening. In retrospect, the 2 above-mentioned patients could have benefitted from antibiotic prophylaxis, but its omission must be weighed against the unnecessary large-scale and long-term use of antibiotics that would have resulted from universal echocardiographic screening.