Risk of XXXX associated with use of @entity4899 .

@entity4899 @entity1 @entity339 @entity12839 @entity337 @entity340
BACKGROUND: Estimates of excess risk of @entity340 among prior users of @entity4899 and @entity12839 have varied widely. Two major forms of bias appear to contribute to this variability and also result in a systematic under-estimation of risk. The first, a form of nondifferential misclassification, is the result of including background, prevalent cases among both exposed and unexposed @entity1 in calculations of risk. The second bias results from not considering the relatively short duration of exposure to drugs. METHODS: We examined data from all available echocardiographic studies reporting the prevalence of @entity337 ( @entity337 ) and @entity339 ( @entity339 ) among @entity1 exposed to @entity4899 or @entity12839 and a suitable control group. We also included one study in which previously existing @entity337 or @entity339 had been excluded. We corrected for background prevalent cases, estimated incidence rates in unexposed @entity1 , and performed a @entity1 -years analysis of apparent incidence rates based on exposure time to provide an unbiased estimate of relative risk. RESULTS: Appearance of new @entity337 was strongly related to duration of exposure (R2 = 0.75, p < 0.0001). The summary relative risk for mild or greater @entity337 was 19.6 (95% CI 16.3-23.5, p < 0.00001); for moderate or greater @entity339 it was 5.9 (95% CI 4.0-8.6, p < 0.00001). CONCLUSION: These findings provide strong support for the view that @entity4899 and @entity12839 are potent causal factors in the development of both aortic and mitral @entity340 .
