The incidence of aneurysmal subarachnoid hemorrhage in youngdong district, Korea

Abstract

Objective: The purpose of this study is to investigate the incidence of aneurysmal subarachnoid hemorrhage (SAH) in Youngdong district for 10 years.

Methods: From Jan. 1997 to Dec. 2006, 732 patients (327 males, 405 females, mean age: 54.8+/-13.1 years) with spontaneous SAH were admitted to our hospital. We reviewed the medical records and radiological findings regarding to the ictus of SAH, location and size of the ruptured aneurysms, Hunt-Hess grade and Fisher grade on admission, personal details such as address, age, and sex, and previous history of medical diseases.

Results: In these 732 patients, 672 cases were confirmed as aneurysmal SAH. Among them, 611 patients (262 males, 349 females, mean age: 54.9+/-13.2 years) came from Youngdong district. The average crude annual incidence of aneurysmal SAH for men, women, and both sexes combined in Youngdong district was 7.8+/-1.7, 10.5+/-2.7, and 9.1+/-2.1 per 100,000 population, respectively. Because of the problems related to the observation period and geographical confinement, it was suspected that the representative incidence of aneurysmal SAH in Youngdong district should be made during the later eight years in six coastal regions. Therefore, the average age-adjusted annual incidence for men, women, and both sexes combined was 8.8+/-1.4, 11.2+/-1.3 and 10.0+/-1.0, respectively in the coastal regions of Youngdong district from 1999 to 2006.

Conclusion: In overall, our results on the incidence of aneurysmal SAH was not very different from previous observations from other studies.

Keywords: Aneurysmal SAH; Epidemiology; Incidence.

Fig. 1

Geographical isolation of Youngdong district. Youngdong district is separated from North Korea by Military Demarcation Line, and faces the East Sea on its eastern coast. Taebaek Mountain range lies west of Youngdong district and interrupts it from Youngseo district. To the south of Youngdong district, even though only a small river lies between Youngdong district and Gyeongsangbuk-do, the patients from even most southern area of Youngdong district must make efforts to access the nearest hospital of Gyeongsangbuk-do taking more than 3 hours using narrow national road, while it takes 1.5 hours to the Gangneung Asan Hospital (hospital symbol).

Fig. 2

The Serial changes of crude annual incidence of aneurysmal subarachnoid hemorrhage in Youngdong district from 1997 to 2006.

Fig. 3

The Comparison of the demographic composition of Youngdong district with that of Korean standard population. There is a higher proportion of the ageing population in Youngdong district than in Korean standard population.

Fig. 4

The Serial changes of the age- and sex-adjusted annual incidence of aneurysmal subarachnoid hemorrhage in Youngdong district from 1997 to 2006. The graph shows exceptionally lower annual incidences during the setting-up period of the hospital (from 1997 to 1998) than those after 1998. The incidences between 1999 and 2006 show annual variations, however, they do not show statistical significance (p>0.05).

Fig. 5

The regional variation of the average annual incidences. The incidences of the three regions located inland are distinctively lower than those of the other six regions facing the East Sea. A : Gangneung Asan Hospital, B : Chuncheon Hallym Medical Center, C : Wonju Christian Hospital.

Fig. 6

Comparison of the average annual incidence rates of aneurysmal SAH for male and female according to the age group. The incidence rates are similar or slightly male-predominant until the 5th decade of life. However, the occurrence of aneurysmal SAH reaches a plateau at age 40 and leveled off thereafter in male, on the other hand, it increases almost linearly after age 40 and peaked in their 7th decades in female.

Fig. 7

The distributions of the locations of ruptured aneurysms according to sex. The most common location of ruptured aneurysm is anterior communicating artery in both sexes. However, posterior communicating artery aneurysms are more frequent in female, and on the contrary, anterior communicating artery aneurysms are more frequent in male.