Prescription of Alzheimer's-specific drugs and long-term preservation of language function are positively associated with early release of regional cerebral metabolic data in a multi-center prospective randomized trial

The Metabolic Cerebral Imaging in Incipient Dementia (MCI-ID) trial is a CMS-sponsored prospective randomized study specifically aimed at acquiring rigorously controlled data with which to address the impact of brain PET scan results on both 1)early evaluation and management of, and 2) long-term clinical outcomes of, Medicare beneficiaries suffering from mild decline in cognition (MDC). MDC patients >65y.o. underwent brain PET at baseline, and were randomized to have results of those scans released immediately, or 2 years later, to their referring physicians. Scans were classified as being positive or negative for an Alzheimer-type neurodegenerative process, according to specific criteria previously documented to be associated upon autopsy with histopathologically confirmed Alzheimer's disease (AD) (JAMA, 2001; 286:2120-2127). Medication and ADAS-Cog data were collected at baseline, and at 6mo. intervals for the subsequent 2 years. Of the first 55 MCI-ID subjects studied by PET, 28 completed sufficient longitudinal neuropsychological follow-up to be included in this analysis and for 21, all of their medication data needed for this analysis have also been centrally archived. Of the 28 subjects, 15 (71.7±5.6yrs) were randomized to immediate release and 13 (73.5±7.1yrs) to delayed release of PET results. Approximately half of the subjects in each arm (53% and 54%) had an Alzheimer-type neurodegenerative pattern: 38% in the immediate-release arm were prescribed drugs specifically indicated for AD treatment within the 2 years of follow-up, while only 13% in the delayed-release arm were. Among the non-AD-PET subjects, those in the immediate-release arm had stable ADAS-Cog language scores (improved by -0.5±0.1points/yr), while subjects randomized to delayed release deteriorated by +3.3±0.2points/yr (P<0.001). In the immediate-release arm, 100% of these subjects demonstrated anxiety levels that decreased, or else remained stable following PET data release, as indexed by HAM-A scores; in contrast, in the delayed-release arm, 84% of subjects demonstrated increased anxiety over the same interval. Initial MCI-ID results indicate that availability of brain PET scan data can lead to clinical benefit by positively impacting both early evaluation/management decisions, as well as long-term neuropsychological function. Moreover, among subjects whose PET scans were negative for AD, immediate release of those results was associated with significantly diminished anxiety.