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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

(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.