Background The diagnosis of hypertension (HTN) and the clinical decisions regarding its treatment are usually based on daytime clinic blood pressure (BP) measurements. However, the correlation between BP levels and target organ damage, cardiovascular (CV) risk, and long-term prognosis, is higher for ambulatory (ABPM) than clinic measurements, both in the general population as well as in patients with diabetes. Given the two-fold increased prevalence of abnormal BP patterns and sleep-time HTN in the diabetic population careful assessment of BP across the entire 24 hours is vital for optimal medical management.

Aim To investigate whether all patients with Type 2 Diabetes Mellitus (T2DM) should have BP assessed using ABPM or whether there are subgroups of T2DM patients who can have BP accurately assessed by using daytime clinic BP monitoring alone.

Methods A total of 30 T2DM patients were included in this study measuring both daytime clinic BP and ABPM in all patients. They were grouped into systolic blood pressure (SBP) <140 mmHg and SBP ≥140 mmHg on daytime clinic measurement. Subjects were asked to complete a questionnaire and biochemical profiles involving cholesterol, HbA1C, creatinine, albumin, urine albumin/creatinine ratio and eGFR were reviewed. Details of medications were noted.

Results On daytime clinic measurement, 63.3% (n=19) had SBP <140 mmHg and 36.7% (n=11) had SBP ≥140 mmHg. Six of nineteen patients (31.6%) with normotensive daytime BP had masked HTN. Conversely, five of eleven patients (45.5%) with hypertensive daytime BP had white coat syndrome. In total, twelve patients (40%) had a high SBP on AMBP (>135 mmHg). Baseline demographic, glycaemic control and CV risk factors data were not significantly different between groups (p>0.05). A third of our patient cohort were not taking regular antihypertensives, three of which had elevated SBP on AMBP (undiagnosed HTN).

Conclusions Due to the high rate of masked hypertension, and marked differences between clinic SBP and ABPM results, ABPM should be performed in all T2DM patients for accurate BP assessment, regardless of baseline demographics, glycaemic control or CV risk factors.