Predictors of cognitive deterioration in subjective cognitive decline: evidence from longitudinal studies and implications for SCD-plus criteria.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of longitudinal cohort studies.
PubMed 36868847 · doi:10.1136/jnnp-2022-330246
What was done
PubMed, Embase, and Cochrane Library were searched through May 2022 (PROSPERO CRD42021281757) for longitudinal studies evaluating risk factors for cognitive deterioration in individuals with subjective cognitive decline (SCD). Multivariable-adjusted effect estimates were pooled using random-effects meta-analysis models, and credibility of evidence was assessed.
What was found
Across 69 longitudinal studies (37 included in the meta-analysis), the mean conversion rate from SCD to any cognitive deterioration was 19.8%, including 7.3% to all-cause dementia and 4.9% to Alzheimer's disease. Sixteen factors emerged as predictors: 5 SCD features (older age at onset, stable SCD, both self- and informant-reported SCD, worry, and SCD in a memory clinic setting), 4 biomarkers (cerebral amyloid-beta deposition, lower Hulstaert formula scores, higher cerebrospinal fluid total tau, and hippocampal atrophy), 4 modifiable factors (lower education, depression, anxiety, and current smoking), 2 unmodifiable factors (APOE epsilon 4 and older age), and worse performance on Trail Making Test B.
Why it matters
This review identifies a comprehensive risk factor profile that supports and supplements the SCD-plus criteria for distinguishing individuals with subjective cognitive decline who are at highest risk of progressing to dementia.
Limits
The abstract states that overall evidence robustness was impaired by risk of bias and heterogeneity among included studies. Specific pooled numerical effect sizes (such as odds ratios or relative risks) and individual study follow-up durations are not reported in the abstract.
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