To study if motivational interviewing (MI) added to standard educational care (SE) improves vascular health in adolescents with poorly controlled type 1 diabetes.
47 adolescents with type 1 diabetes of at least 2 years duration and HbA1c > 75 mmol/mol (> 9.0%) on two visits were randomized to MI+SE or SE, clinicaltrials.gov; NCT02637154.
39 adolescents (20 MI + SE) completed the study. At 12 months, vascular health parameter changes were not statistically significantly different between MI + SE and SE (carotid-femoral pulse-wave velocity (PWV): mean difference 0.052 m/s (95% CI -0.395 – 0.500, p=0.81); carotid-radial PWV: 0.118 m/s (95% -0.478 – 0.713, p=0.69), carotid intima-media thickness (IMT): 0.002 mm (95% CI -0.37 – 0.40, p=0.93), systolic blood pressure (SBP) z-score: 0.495 (95% CI -0.099 – 1.09, p=0.10). At baseline, duration of type 1 diabetes was associated with radial IMT (r=0.430, p=0.007) and cfPWV (r=0.373, p=0.018), and carotid, femoral and brachial IMT were correlated with CGM-SD (r=0.440, p=0.017; r=0.377, p=0.048; r=0.387, p=0.038). There was an inverse association between CGM time-in-range (3.9-10.0 mmol/L) and crPWV (r=-0.476, p=0.022) changes. SBP change was associated with BMI change (r=0.374, p=0.019) and IMT change (r=0.461, p=0.016 for carotid IMT; r=0.498, p=0.010 for femoral IMT).
There was no effect of MI added to SE on vascular health parameters. Although disease duration and glycemic control were associated with vascular health at baseline, there were only limited associations between glycemic control and vascular health parameter changes. Vascular health parameter changes were interrelated suggesting clustering of cardiovascular risk.