Stroke incidence time trends

The most recent studies of time trends in stroke incidence do suggest that age-specific incidence is now falling (Sarti et al. 2003 Rothwell et at. 2004 Anderson et al. 2005 Hardie et al. 2005). Between the periods 1981-1984 and 2002-2004, a 40% reduction in the incidence of fatal and disabling stroke was found in Oxfordshire, UK (Rothwell et al. 2004), although this reduction was less marked in the oldest old (Fig. 1.3). High-quality population-based studies of time trends in TIA and minor stroke are lacking. However, moderate rises in TIA incidence were reported in Oxfordshire, UK, between the periods... 

In view of the perceived benefit of aspirin in the secondary prevention of stroke and myocardial infarction, two large trials involving physicians as subjects were initiated to study the effect of aspirin in the primary prevention of arterial thrombosis. In the American study, 22,000 volunteers (age 40 to 84 years) were randomly assigned to take 325 mg of aspirin every other day or placebo. The trial was halted early, after a mean follow-up of 5 years, when a 45% reduction in the incidence of myocardial infarction and a 72% reduction in the incidence of fatal myocardial infarction were noted with aspirin treatment. However, total mortality was reduced only 4% in the aspirin group, a difference that was not statistically significant, and there was a trend for a greater risk of hemorrhagic stroke with aspirin. Thus, the prophylactic use of aspirin in an apparently healthy population is not recommended at this time, unless there are risk factors for cardiovascular disease. 

Prospective studies unexpectedly indicated that the incidence of heart disease and stroke in older postmenopausal women treated with conjugated estrogens and a progestin was initially increased, although the trend reversed with time. While it is not clear if similar results would occur with different drugs/doses or in different patient populations, estrogens (alone or in combination with a progestin) should not be used for the treatment or prevention of cardiovascular disease. 

In a recent meta-analysis of the six randomized trials, patient transfer for primary PCI was associated with a 42% reduction in the composite endpoint (death/reinfarction/stroke), compared with a strategy of on-site thrombolysis (Fig. 4.10) (95). This was driven mainly by a reduction in the incidence of reinfarction (68% reduction) and stroke (56% reduction), but there was also a trend toward improved survival with PCI. Overall, these findings strongly support community wide adoption of a transfer strategy for mechanical reperfusion, as long as patient transfer can be accomplished within time intervals similar to those described in the randomized trials. The challenge now is to overcome logistical obstacles and replicate these impressive results in clinical practice. 

---