Differential vascular effects of aspirin in people with Type 2 diabetes without cardiovascular disease and matched controls without diabetes

Aim We investigated whether the effect of low‐dose aspirin on endothelium‐dependent vasodilation and arterial stiffness in people with Type 2 diabetes is different from a matched control group. We examined acute and chronic effects, and effects over the 24h dosing interval. Methods In an open‐label parallel group intervention study, we included 21 participants with Type 2 diabetes and 21 age‐ and sex‐matched controls. Endothelium‐dependent vasodilation was assessed as the reactive hyperaemia index (ln RHI ) measured by peripheral arterial tonometry (Endo PAT ® ). Arterial stiffness was assessed as pulse wave velocity ( PWV ) measured by applanation tonometry (SphygmoCor ® ). Measurements were performed prior to aspirin intake and 1h after aspirin administration (75 mg). Participants were then treated for 6 days, and measurements were repeated at 24 h and 1 h after aspirin intake. Results Baseline ln RHI did not differ between groups. The controls had an immediate increase in ln RHI after the first aspirin tablet. This was not observed in participants with diabetes (difference between groups; P < 0.05). After 1 week, both groups demonstrated increased ln RHI compared with baseline ( P < 0.01). In participants with diabetes, ln RHI was significantly lower 24 h after aspirin administration compared with 1 h after administration ( P < 0.05). This difference was not observed in controls ( P = 0.84, difference between groups; P = 0.12). The effect on PWV did not differ between groups. Conclusion Aspirin had a reduced immediate effect on endothelium‐dependent vasodilation in participants with diabetes. Both groups had improved endothelial function after 1 week of treatment. Further, the effect of aspirin on endothelial function may be declining during a 24 h dosing interval in people with Type 2 diabetes. (Clinical Trial Registry No: 2016‐000515‐32)