Patient populations in clinical studies of donepezil in vascular dementia

There are difficulties in accurately defining patients with vascular dementia (VaD) and, therefore, little is known about the characteristics of this population.

To examine the population characteristics in patients with VaD enrolled in two randomized, double-blind, placebo-controlled, 24-week clinical trials of the efficacy and tolerability of the acetylcholinesterase inhibitor donepezil.

Enrolled patients had probable or possible VaD, classified according to NINDS-AIREN criteria. Patients were excluded if they had a diagnosis of Alzheimer's disease or dementia caused by other conditions not associated with the cardiovascular system.

A total of 1,219 patients, 73% with probable VaD and 27% with possible VaD, were enrolled. Patients had a mean Hachinski score of 9.7, with memory impairment the most prominent feature of their dementia. Sixty-eight percent of patients had a history of at least one stroke and 28% of patients had a history of transient ischemic attack before dementia. In the 99% of patients who had abnormal computer-assisted tomography or magnetic resonance imaging scans, cortical and subcortical infarcts were among the lesions observed, with significant white-matter lesions also present in some patients. Seventy-three percent of patients had experienced an abrupt onset of cognitive symptoms. Vascular risk factors were prominent and included hypertension (70%), smoking (62%), and hypercholesterolemia (39%).

The patients enrolled in these trials had probable or possible VaD; these patients exhibited a history of cerebrovascular disease and a broad range of comorbid cardiovascular conditions. The large number of patients enrolled will permit a thorough examination of the efficacy and tolerability of donepezil in VaD.