Chlamydia pneumoniae accompanied by inflammation is associated with the progression of atherosclerosis in CAPD patients: a prospective study for 3 years

Abstract

BACKGROUND: The causes of accelerated atherosclerosis in end-stage renal disease (ESRD) patients are unknown, although recent studies have suggested that Chlamydia pneumoniae (Cp) infection and inflammation might be contributing factors. We aimed to evaluate the association of carotid atherosclerosis progression with Cp infection and inflammation in patients undergoing peritoneal dialysis (PD). METHODS: This is a prospective observational study. A total of 52 non-diabetic prevalent PD patients were included. The intima-media thickness of a common carotid artery (CCA-IMT) was measured at baseline and after 36 months by B-mode ultrasonography. Serum antibodies to Cp and inflammatory markers were obtained at the time of initial measurement of the CCA-IMT. RESULTS: CCA-IMT progressors (deltaCCA-IMT > or = 0.015 mm/year) had a higher prevalence of seropositivity for Cp IgA antibody, a higher level of Cp IgA antibodies indices, log IL-(interleukin-)6, and intercellular adhesion molecule-1 (ICAM-1) compared to the non-progressors (deltaCCA-IMT < 0.015 mm/year). On multivariate analysis, Cp IgA index and log IL-6 were independent risk a factors for CCA-IMT progression. Also, Cp IgA index had independent positive correlation with the magnitude of annual deltaCCA-IMT. Cp IgA antibody seropositive patients showed significantly higher mean annual deltaCCA-IMT than seronegative patients. Moreover, patients with both positive Cp IgA antibodies and elevated IL-6 above the median level showed higher deltaCCA-IMT than those with either factor alone. CONCLUSIONS: Our data showed that Cp and inflammation were significant risk factors of CCA-IMT change in PD patients. This study strengthens evidence that Cp is involved in the pathogenesis of atherosclerosis and also suggests that the effect of Cp infection under high inflammatory status might be a risk factor for progression of atherosclerosis.