Aims: A systematic review and meta-analyses to explore and quantify associations between SAA and adverse outcomes in older people.

Methods: A literature-search in Ovid MEDLINE, EMBASE, PsycINFO and IPA from 1946-2014 was completed. The primary outcomes of interest were cognitive and functional impairments associated with SAA. The Cochrane Risk-Bias tool was used to assess bias in randomised controlled trials (RCTs), and the Newcastle-Ottawa Scale to assess the quality of non-RCTs. Meta-analyses were conducted for RCTs and cohort studies separately.

Results: 33 studies that met the inclusion criteria. This includes 4 RCTs, 5 prospective cohort studies, 3 longitudinal studies, 17 cross-sectional studies, and 4 case-control studies. 73% of the studies examined an association between SAA and cognitive outcomes, and 27% examined an association with functional outcomes. The meta-analysis on 4 RCTs showed no association with higher SAA and cognitive performance (I2 = 89.38%, H2 = 25.53 and p-value < .05) however, the pooled data from 4 observational studies showed elevated SAA was associated with reduced cognitive performance (I2 = 0.00%, H2 = 3.37 and p-value = 0.34).

Discussion: This systematic review summarises the limitations of the SAA on predicting cognitive and functional outcomes in older people. SAA measured by receptor bioassay is flawed and its use in older people with multimorbidity and polypharmacy is questionable. The variability associated with SAA measurements limits its widespread acceptance as a biomarker for cognitive impairment in older people.