MCI mimics common symptoms before Alzheimer’s diagnosis

Patients recently diagnosed with Alzheimer’s disease had an increased prevalence of diagnoses for neuropsychiatric conditions that mimic symptoms of mild cognitive impairment in a large retrospective, case-control study.

The findings underscore the need for an instrument designed to help clinicians differentiate mild cognitive impairment (MCI) from other neuropsychiatric conditions, a project statistician with Deerfield, Illinois — based in the Clinical Trials Conference on Alzheimer’s Disease.

In an effort to characterize the three-year period immediately preceding the first diagnosis of Alzheimer’s disease (AD) and the first 6 months after diagnosis, Medicare data were used to identify risk and prognostic factors in 28,879 newly diagnosed AD patients with a mean age of 79 years. The researchers also randomly selected a control cohort of 28,879 patients and matched them in a 1:1 fashion with the AD cohort.

The percentage of AD patients, compared with controls, who had a diagnosis of MCI at 36 months before AD diagnosis to 6 months after AD diagnosis increased from 0.2% to 5.2% to 7.6%, compared with controls (0% at all three time points). The same significant trend occurred for diagnoses of AD-related conditions or dementia or frontotemporal dementia, dementia with Lewy bodies, and memory loss.

The steeper slope of the increase in prevalence in the 6 months pre·index period seems to suggest that diagnosis of these disorders may lead a physician to test for AD, while the 6 months post-index increase could indicate higher awareness among physicians of the need to test AD patients for other similar diagnoses.

Over time, a higher percentage of AD patients vs. controls also had anxiety disorder and depression. The percentage of patients with cerebrovascular disease increased with time.