Chlamydia pneumoniae infection and cerebral infarction risk: a meta-analysis

Chlamydia pneumoniae infection and the risk of cerebral infarction have been previously studied in several publications; however, conflicting results have been reported. This meta-analysis assessed whether C. pneumoniae infection was associated with risk of cerebral infarction.

Systematic computerized searches of the PubMed and Web of Knowledge were performed. Adjusted odds ratio and 95% confidence interval from original studies were extracted for combined meta-analysis.

Twenty-three studies with 2924 cerebral infarction patients and 4692 control patients were included in the meta-analysis. When the positive C. pneumoniae infection was defined by microimmunofluorescence-detected immunoglobulin A, the pooled odds ratio between two groups was 2.04 (95% confidence interval 1.42-2.9). In the most frequently used immunoglobulin A ≥1:16 sub-group, the pooled odds ratio was 2.07 (95% confidence interval 1.31-3.26). When the infection was defined by enzyme-linked immunosorbent assay-detected immunoglobulin A, the pooled odds ratio was 2.89 (95% confidence interval 1.23-6.81). When the infection was defined by microimmunofluorescence-detected immunoglobulin G, the pooled odds ratio was 1.46 (95% confidence interval 1.18-1.81). In the most frequently used immunoglobulin G ≥1:32 sub-group, the pooled odds ratio was 1.43 (95% confidence interval 1.06-1.92). When the infection was defined by enzyme-linked immunosorbent assay-detected immunoglobulin G, the pooled odds ratio was 1.54 (95% confidence interval 0.86-2.74). No significant publication bias was found. Sensitivity analyses showed the results were robust.

(1) This meta-analysis indicated that C. pneumoniae infection was significantly associated with an increased risk of cerebral infarction. (2) Compared with anti-C. pneumoniae immunoglobulin G, anti-C. pneumoniae immunoglobulin A seemed more effective for predicting the risk of cerebral infarction. (3) No evidence existed that anti-C. pneumoniae-immunoglobulin G detected by enzyme-linked immunosorbent assay could predict the risk of cerebral infarction.