Ambulatory blood pressure and arterial stiffness in individuals with type 1 diabetes.

Aims/hypothesis: This study aimed to assess the use of ambulatory BP monitoring (ABPM) to identify the presence of masked, nocturnal and white-coat hypertension in individuals with type 1 diabetes, patterns that could not be detected by regular office-based BP monitoring alone. We also analysed associations between BP patterns and arterial stiffness in order to identify individuals at cardiovascular risk.

Methods: This substudy included 140 individuals with type 1 diabetes from the Helsinki metropolitan area, who attended the Finnish Diabetic Nephropathy Study (FinnDiane) Centre in Helsinki between January 2013 and August 2017. Twenty-four hour ABPM and pulse wave analysis were performed simultaneously using a validated non-invasive brachial oscillometric device (Mobil-O-Graph). Definitions of hypertension were based on the European Society of Hypertension guidelines. Masked hypertension was defined as normal office BP (BP obtained using a standardised automated BP device) but elevated 24 h ABPM, and white-coat hypertension as elevated office BP but normal 24 h ABPM.

Results: A total of 38% of individuals were normotensive and 33% had sustained hypertension, while 23% had masked and 6% had white-coat hypertension. About half of the cohort had increased absolute levels of night-time BP, half of whom were untreated. In the ambulatory setting, central BP and pulse wave velocity (PWV) were higher in participants with masked hypertension than in those with normotension (p ≤ 0.001). In a multivariable linear regression model adjusted for age, sex, BMI, antihypertensive treatment and eGFR, masked hypertension was independently associated with higher 24 h PWV (β 0.50 [95% CI 0.34, 0.66]), but not with PWV obtained during resting conditions (adjusted β 0.28 [95% CI -0.53, 1.10]), using normotension as the reference group.

Conclusions/interpretation: ABPM analysis revealed that one-quarter of the participants with type 1 diabetes had masked hypertension; these individuals would not have been detected by office BP alone. Moreover, arterial stiffness was increased in individuals with masked hypertension. These findings support the use of ABPM to identify individuals at risk of cardiovascular disease.