Follow-up of participants with subjective cognitive decline from Tremembé epidemiologic study, Brazil

Subjective cognitive decline is defined as a self-perceived cognitive decline but with normal performance in neuropsychological assessments. OBJECTIVE: To verify the evolution of patients diagnosed with subjective cognitive decline compared to the cognitively normal group without any concern. METHODS: This is a follow-up study based on data analysis from the Tremembé epidemiologic study, in Brazil. The 211 individuals classified as cognitively normal and 174 diagnosed as having subjective cognitive decline at baseline were invited to participate. RESULTS: After a median follow-up time of five years, 108 subjective cognitive decline participants (62.0%) were reassessed. Of these, 58 (53.7%) kept this diagnosis, whereas 14 individuals (12.9%) progressed to mild cognitive impairment and 5 (4.6%) to dementia. In the cognitively normal group, 107 (50.7%) were reassessed, of which 51 (47.7%) were still classified likewise, 6 (5.6%) evolved to mild cognitive impairment and 9 (8.4%) to dementia. The presence of cognitive decline had a significant association with increasing age and depression symptoms. Considering the total number of baseline participants in each group: the subjective cognitive decline group showed higher percentage of mild cognitive impairment (p=0.022) and no difference was found in progression to dementia (p=0.468) between the groups after follow-up assessment. CONCLUSION: Most subjective cognitive decline participants at baseline kept their cognitive complaint at follow-up and this group progressed more to mild cognitive impairment than the other group. No difference in the progression to dementia was found, despite the higher incidence of dementia in the cognitively normal group.