Effect of basal insulin and omega 3 fatty acids on cognitive impairment in dysglycaemia: An exploratory analysis of the ORIGIN trial

Abstract

AimThe outcomes reduction with an initial glargine intervention (ORIGIN) trial reported that, allocation to insulin glargine‐mediated normoglycaemia versus standard care, and to omega 3 fatty acids versus placebo had a neutral effect on cognitive test scores when analysed as continuous variables. Analyses of these scores as standardized categorical variables using a previously validated strategy may yield different results.Materials and MethodsThe ORIGIN trial recruited participants with dysglycaemia and additional cardiovascular risk factors from 573 sites in 40 countries. They completed a mini mental state examination and a subset completed the digit symbol substitution test at baseline and up to three subsequent visits. The effect of the interventions on country‐standardized substantive cognitive impairment, defined as the first occurrence of a baseline‐adjusted follow‐up mini mental state examination or digit symbol substitution test score ≥1.5 standard deviations below the baseline mean score in each participant's country was assessed using Cox proportional hazards models.ResultsDuring a median follow‐up of 6.2 years, 2627 of 11 682 people (22.5%) developed country‐standardized substantive cognitive impairment. The hazard of this outcome was reduced by 9% (hazard ratio 0.91, 95% confidence interval 0.85, 0.99; p = .023) in participants assigned to insulin glargine (21.6%) versus standard care (23.3%). Conversely, the hazard of this outcome was not affected by assignment to omega 3 fatty acid versus placebo (hazard ratio 0.93, 95% confidence interval 0.86, 1.01; p = .074).ConclusionsIn this post hoc exploratory analysis, insulin glargine‐mediated normoglycaemia but not omega 3 fatty acids reduced the hazard of substantive cognitive impairment in people with dysglycaemia and additional cardiovascular risk factors.