Risk profile of @entity438 : XXXX rate is not constant after formation.

@entity1 @entity438 @entity510 @entity397 @entity439 @entity1756
BACKGROUND AND PURPOSE: Management of asymptomatic unruptured @entity438 remains controversial, and recent prospective follow-up studies showed that the @entity397 rate of small @entity439 is very low. These results are inconsistent with the finding that the majority of @entity1756 in @entity1 with @entity510 are small. METHODS: A Markov model was constructed to simulate the natural history of @entity438 . All epidemiological and statistical data obtained from the Portal Site of Official Statistics of Japan (e-Stat) were adjusted to the standardized age distribution. From the selected data of @entity439 formation, the prevalence of unruptured @entity439 was estimated as 1.45% and the incidence of @entity510 calculated to be 19.7/100 000/year in the whole standardized population. RESULTS: The function for @entity397 rate constant with time was first analyzed. Selected values for annual @entity397 rates of 0.3%, 0.5%, 0.7%, and 1.0% showed inconsistencies in the relationship between the prevalence of unruptured @entity439 and the incidence of @entity510 . Next, the function for a short period of high risk followed by a long period of low risk was considered. @entity397 rates of 0.5%, 0.7%, and 1.0% indicated epidemiological compatibility with additional @entity397 rates of 20%, 15%, and 10%, respectively. CONCLUSIONS: This study suggests that some @entity439 shortly after formation and thus are rarely detected as unruptured @entity439 . Most @entity439 without @entity397 remain stable for the remainder of life through some healing process, and prophylactic treatment for incidentally identified small unruptured @entity439 has no rationale.
