Difficulties With Activities of Daily Living Strong Predictor of Progression to Dementia
By Caroline Cassels
Medscape Medical News
September 16, 2009 — Individuals with mild cognitive impairment (MCI) who have difficulties with activities of daily living are more likely to progress to dementia than their counterparts who do not have difficulty performing routine activities, new research suggests.
This finding held true regardless of whether MCI patients were recruited from a clinic-based population or from the community.
Investigators from the University of California–Davis found that other than recruitment source, the only factor associated with conversion from MCI to dementia was the degree of functional impairment at study outset. No demographic, cognitive, or neuroimaging variables predicted this progress, the authors report.
Led by Sarah Tomazewski Farias, PhD, the study is published in the September issue of the Archives of Neurology.
Annual conversion rates from MCI to dementia range from a high of 10% to 15% in clinic samples to substantially lower rates of 3.8% to 6.3% in community-based studies.
"Clearly patients with MCI compose a heterogeneous group, of whom not all rapidly convert to dementia. As such it is important to identify risk factors for progressing rapidly among individuals diagnosed with MCI," the authors write.
In the prospective longitudinal study, researchers sought to establish whether the rates of conversion from MCI to dementia differ according to recruitment source and, if so, to investigate factors that might explain this discrepancy.
A total of 111 participants were included in the study. Of these, 51 patients (46%) were recruited from a university-based memory disorders clinic on suspicion of cognitive decline and 60 patients (54%) were recruited directly through community outreach.
All participants underwent annual clinical evaluations, diagnostic imaging, routine laboratory tests, and neuropsychological evaluations.
During an average of 2.4 years of follow-up, 28 individuals progressed from MCI to dementia, including 23 patients from the clinic and 5 from the community. Annually, 13% of the clinic-based group and 3% of the community group converted to dementia.
"Thus, regardless of whether an individual was a clinic patient or recruited directly from the community, more functional impairment at baseline was an important risk factor for future conversion to dementia," the authors write.
The authors have disclosed no relevant financial relationships.
