Reduction in mortality due to various forms of heart disease is one of the larger recent past drivers of the slow upward trend in adult and elderly life expectancy. A reduction in the incidence of Stroke is most likely due to many of the same underlying advances in medical practice. It is welcome, but worth remembering that the technologies and approaches that have created the present trend in life expectancy have very little to do with what lies ahead. The whole approach to aging is changing, and future trends will be very different from the present ones, because researchers will be trying to actually treat the causes of aging and all age-related disease rather than only patching the symptoms.
A new analysis of data from 1988-2008 has revealed a 40% decrease in the incidence of stroke in Medicare patients 65 years of age and older. This decline is greater than anticipated considering this population's risk factors for stroke, and applies to both ischemic and hemorrhagic strokes. Investigators also found death resulting from stroke declined during the same period. The team identified more than one million stroke events from 1988 to 2008, of which 87.3% were ischemic and 12.7% hemorrhagic strokes. The analysis showed a reduction in ischemic strokes from 927 per 100,000 in 1988 to just 545 per 100,000 in 2008. Hemorrhagic strokes decreased from 112 per 100,000 to 94 per 100,000 over the same time period, primarily among men. Data indicated that stroke mortality also declined. The risk-adjusted 30-day mortality rate for ischemic strokes fell from 15.9% in 1988 to 12.7% in 2008. For hemorrhagic stroke, the mortality rates declined slightly from 44.7% in 1988 to 39.3% in 2008.
The study was constructed to analyze stroke cases over the past two decades, not to investigate causation; however, researchers did find evolving patterns in the risk factors associated with strokes. Although the prevalence of diabetes mellitus increased over time, other risk factors, such as cigarette smoking, measured systolic blood pressure, and total cholesterol values, decreased.
The decline in stroke rates paralleled increasing use of antihypertensive and statin medications and might explain the reduction in stroke rates. "Antihypertensive medications reduce the risk of stroke by approximately 32% and statins by approximately 21%. Stroke rates seem to decrease most sharply after year 1998, approximately when statin use became more prevalent. If true, then this illustrates how medical interventions have resulted in significant improvements in health on a population level."