Association between serological evidence of past Coxiella burnetii infection and atherosclerotic cardiovascular disease in elderly patients

Abstract

Q fever, caused by Coxiella burnetii, may cause vascular complications, but the role that this infection may play in the development of atherosclerotic cardiovascular disease remains unknown. This study examined the association between Q fever serology and cardiovascular disease in a region where Q fever is endemic. A case-control study was conducted in the Hospital Universitario de Burgos (Spain) between February 2011 and June 2012. A total of 513 samples were tested, from 454 hospitalized patients ≥65 years old, of whom 164 were cases (patients with prevalent or incident coronary heart, cerebrovascular or peripheral artery, disease) and 290 controls (patients without cardiovascular disease). Serum IgG antibody phase II titres against Q fever were determined by immunofluorescence assay. Seropositivity (titres ≥1:256) was detected in 84/164 (51.2%) cases and in 109/290 (37.6%) controls (p = 0.005; OR, 1.7; 95% CI, 1.1-2.5). This ratio increases when adjusted for sex, hypertension, dyslipidaemia, smoking, diabetes and atrial fibrillation (OR, 2.6; 95% CI, 1.5-4.7). The geometric mean titre (GMT) for C. burnetii phase II assay was higher in cases than in controls (p = 0.004). We found no significant relationship between cardiovascular disease and C. pneumoniae, and Cytomegalovirus seropositivity (both determined by the IgG ELISA method). In conclusion, serological evidence of past Q fever is associated with atherosclerotic cardiovascular disease in elderly patients in an endemic region.

Persistent Q fever and ischaemic stroke in elderly patients

“…In this study, the patients who had acute Q fever had a higher risk of suffering from a cerebrovascular accident and ischaemic heart disease after 12 years. Following this line of research , our group has recently demonstrated an association between serological markers consistent with past infection by C. burnetii and cardiovascular disease in elderly hospitalised patients from a region where the infection is endemic [23 ]. However, it is unknown whether persistent infection may act in a similar way, and if any subtype of cardiovascular disease may be particularly involved in this association.…”

“…Details of the recruitment and patient selection have been published previously [23]. The current study is an extension of previous one, focusing on ischaemic stroke and persistent or chronic C.burnetti infection, and conducted by expanding the sample (454 to 634 patients according to the size of the sample calculated), serology (antibody titres IgG phase I against Q fever), and new secondary data.…”

“…Age also promotes changes in the immune and inflammatory system that could produce the persistence or reactivation of certain infections, as Q fever [18][19][20][21][22][23]. However, there are no studies that specifically analyse a possible association between stroke and these infections in elderly subjects, or any other age range.…”

Reply: Coxiella burnetii and complicated atherosclerosis: perhaps neither innocent nor bystanders

“…We thank D. Chatzidimitriou et al for their letter about our article [1]. It refers to the controversies that have arisen over the years in this field.…”

Coxiella burnetii: a new player in atherosclerosis or an innocent bystander?

“…We are grateful to Gonzalez-Quijada et al [1] for providing novel insight into the long-lasting infection hypothesis in their study. Bearing in mind that several controversies have arisen over the years in this field, we believe that some issues need to be further clarified before safe conclusions can be reached.…”