373-P: A Systematic Review and Meta-analysis of the Impact of Acute Hypoglycemia on Cognitive Function in Adults with Type 1 Diabetes

Acute hypoglycemia impacts negatively on cognitive function. However, it remains unclear which specific domains of cognitive function are affected, and the extent to which level of hypoglycemia modifies this relationship. We conducted a systematic review and meta-analysis to investigate the impact of controlled hyperinsulinaemic hypoglycemia on cognitive function in adults with type 1 diabetes, following PRISMA guidelines. Experimental studies comparing cognitive function task performance during euglycemia and hypoglycemia were eligible for inclusion. Preliminary analyses were conducted on 38 studies, involving 54 cognitive task outcomes across three domains of cognitive function of varying complexity: attention/information processing speed (simplest) , working memory, and complex reasoning (most complex) . Three-level meta-analyses of the standardized mean differences (SMD) in performance during euglycemia and hypoglycemia, moderated by hypoglycemia level (Mdn=2.51; range=1.98-3.5 mmol/l) were conducted for each domain, with study and task as random effects to allow inclusion of multiple effect sizes per study. Hypoglycemia significantly impaired performance on all domains, with large effect sizes for attention/information processing speed (SMD=-1.17, 95% CI:-1.60 to -0.74) and working memory (SMD=-0.84, CI:-1.to -0.63) , and a medium effect size for complex reasoning (SMD=-0.61, CI:-0.99 to -0.23) . The degree of hypoglycemia significantly moderated this relationship for working memory only, such that for every 1mmol/l decrease in glucose level, performance was reduced by SMD=0.84 (CI:0.2 to 1.49) . These findings suggest that the impact of hypoglycemia on cognitive function is related to the cognitive domain complexity, with more impaired performance on simpler relative to more complex tasks. Further, degree of hypoglycemia may be differentially related to performance depending on the domain of cognitive function.