Optimal duration of treatment for Q fever endocarditis outlined

January 01, 0001

Optimal duration of treatment for Q fever endocarditis outlined

Q fever endocarditis caused by Coxiella burnetii is a potentially fatal disease characterised by a chronic evolution. To assess the long-term outcome and identify prognostic factors for mortality, surgical treatment, and serological changes in Q fever endocarditis, the researchers from France did a retrospective study in the French National Referral Centre. Patients included were diagnosed with Q fever endocarditis at the author's centre from 1983 to 2006, and followed up for a minimum of 3 years for each patient. History and clinical characteristics were recorded with a standardised questionnaire. 104 patients were identified for inclusion in the study, although one was lost to follow-up; median follow-up was 100 months (range 37—310 months).

18 months of treatment was sufficient to sterilise the valves of all the patients except three, and 2 years of treatment sterilised all valves except one. The major determinants associated with mortality were age (hazard ratio 1.11), stroke at diagnosis (7.09), endocarditis on a prosthetic valve (6.04), an absence of a four-times decrease of phase I IgG and IgA at 1 year (5.69), or the presence of phase II IgM at 1 year (12.08). Surgery was associated with heart failure (2.68) or a cardiac abscess (4.71). The determinants of poor serological outcome were male sex (0.47), a high level of phase I IgG (0.65), and a delay in the start of treatment with hydroxychloroquine (0.20). Factors associated with relapse were endocarditis on a prosthetic valve (21.3) or treatment duration less than 18 months (9.69). All these findings were significant.

The researchers concluded: "The optimum duration of treatment with doxycycline and hydroxychloroquine in Q fever endocarditis is 18 months for native valves and 24 months for prosthetic valves. This duration should be extended only in the absence of favourable serological outcomes. Patients should be serologically monitored for at least 5 years because of the risk of relapse."

This is helpful data to base treatment plans on.

For the full abstract, click here.

The Lancet Infectious Diseases 10(8):527-535 August 2010
© 2010 Elsevier Ltd
Long-term outcome of Q fever endocarditis: a 26-year personal survey. Matthieu Million, Franck Thuny, Hervé Richet and Didier Raoult. Correspondence to Didier Raoult: didier.raoult@gmail.com

Category: K. Circulatory. Keywords: long term, outcome, Q fever, endocarditis, survey, retrospective study, journal watch.
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 20 August 2010

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