Trends in subarachnoid haemorrhage in elderly persons from Nagasaki, Japan: analysis of the Nagasaki SAH Data Bank for cerebral aneurysm, 1989-1998.

BACKGROUND

Many industrialized countries are facing a volumetric growth of the senior population. We studied the trends in the incidence and outcome of subarachnoid haemorrhage (SAH) in patients aged >or=70 years.

METHOD

We retrospectively reviewed the cases of 1030 patients registered in the Nagasaki SAH Data Bank from 1989 to 1993 and 1274 patients registered from 1994 to 1998.

FINDINGS

The annual age-adjusted incidence of SAH per 100,000 increased only in women, from 15.4 in the 1989-1993 period to 19.7 in the 1994-1998 period. The average annual incidence of SAH per 100,000 women in the elderly aged >or=70 years increased significantly from 44.3 in the first period to 58.2 in the second period. In patients aged >or=70 years, the proportion of high-grade SAH (Hunt & Kosnik Grade IV and V) significantly increased from 27.2% in the first 5 years to 38.2% in the second 5 years. In patients aged<70 years, it increased slightly from 23.4% to 26.7%. The rate of favorable outcomes significantly fell from 43.9% (first period) to 30.9% (second period) in patients aged >or=70 years but was stable in patients aged<70 years.

INTERPRETATION

Although the incidence of elderly patients with SAH in our study is compatible with or higher than that of other reports, we believe that elderly patients (especially women) with high-grade SAH may not have all been identified. When we discuss the management of ruptured and unruptured aneurysms in the elderly, we should bear these trends of SAH in mind.