Effect of Linagliptin on Cognitive Performance in Patients With Type 2 Diabetes and Cardiorenal Comorbidities: The CARMELINA Randomized Trial

OBJECTIVE Type 2 diabetes is associated with cognitive dysfunction and an increased dementia risk, particularly in individuals with concomitant cardiovascular and/or kidney disease. Incretin therapies may modulate this risk via glycemic and nonglycemic pathways. We explored if the dipeptidyl peptidase 4 inhibitor linagliptin could prevent cognitive decline in people with type 2 diabetes with cardiorenal disease. RESEARCH DESIGN AND METHODS The CArdiovascular and Renal Microvascular outcomE study with LINAgliptin (CARMELINA)-COG substudy was an integral part of CARMELINA (NCT01897532) that randomized participants with cardiorenal disease to linagliptin 5 mg or placebo once daily (1:1), in addition to standard of care. The primary cognitive outcome was the occurrence of accelerated cognitive decline at the end of treatment, defined as a regression-based index score <= 16th percentile on the Mini-Mental State Examination (MMSE) or a composite measure of attention and executive functioning and analyzed in participants with a baseline MMSE >= 24. Effects across subgroups by baseline factors, as well as absolute cognitive changes, were also assessed. RESULTS Of the 6,979 participants in CARMELINA, CARMELINA-COG included 1,545 (mean +/- SD age, 68 +/- 8 years; MMSE, 28.3 +/- 1.7; estimated glomerular filtration rate, 52 +/- 23 mL/min/1.73 m(2); and HbA(1c), 7.8 +/- 0.9% [61.4 +/- 10.1 mmol/mol]). Over a median treatment duration of 2.5 years, accelerated cognitive decline occurred in 28.4% (linagliptin) vs. 29.3% (placebo) (odds ratio 0.96 [95% CI 0.77, 1.19]). Consistent effects were observed across subgroups by baseline characteristics. Absolute cognitive performance changes were also similar between treatment groups. CONCLUSIONS In a large international cardiovascular outcome trial in people with type 2 diabetes and cardiorenal disease, linagliptin did not modulate cognitive decline over 2.5 years.