BLOOD pressure thresholds significantly influenced the diagnosis of nocturnal hypertension among people with Type 2 diabetes, with lower American guideline thresholds increasing prevalence from 62.5% to 83.3%, according to a cross-sectional study involving 634 participants.
Despite this substantial increase, the overall prevalence of isolated nocturnal hypertension remained largely unchanged, although many individuals were reclassified into different ambulatory blood pressure categories.
Researchers investigated how different ambulatory blood pressure thresholds influenced nocturnal hypertension prevalence and individual classification among people living with Type 2 diabetes.
The cross-sectional study included 634 participants who underwent ambulatory blood pressure monitoring.
Researchers compared diagnostic classifications based on thresholds established by the European Society of Hypertension and International Society of Hypertension (ESH/ISH) with those from the American College of Cardiology and American Heart Association (ACC/AHA).
The analysis assessed nocturnal hypertension prevalence, isolated nocturnal hypertension (INH), agreement between classification systems, and changes in individual ambulatory blood pressure phenotypes.
Using ESH/ISH thresholds, nocturnal hypertension was identified in 62.5% of participants (95% CI: 58.7–66.2).
Applying the lower ACC/AHA thresholds increased prevalence to 83.3% (95% CI: 80.4–86.2), representing a difference of 20.8 percentage points.
However, the prevalence of INH remained remarkably similar between classification systems, increasing only slightly from 21.6% under ESH/ISH thresholds to 22.1% under ACC/AHA criteria.
Despite comparable overall INH prevalence, agreement between the classification systems was moderate (unweighted κ=0.475), indicating substantial differences in which individuals received particular diagnoses.
More than half of participants classified as having INH under ESH/ISH thresholds were reclassified as having sustained hypertension using ACC/AHA criteria.
Conversely, more than half of those identified with INH under ACC/AHA thresholds had previously been considered normotensive according to ESH/ISH criteria.
These findings demonstrated that similar prevalence estimates could conceal considerable differences in individual diagnostic classification.
Exploratory, unadjusted analyses suggested differences in age, sex, and office blood pressure between subgroups classified as having INH.
However, the researchers emphasised that the clinical and prognostic implications of these differences remain uncertain.
The findings highlighted the importance of considering diagnostic thresholds when interpreting ambulatory blood pressure results in people with Type 2 diabetes.
Although lower ACC/AHA thresholds identified substantially more individuals with nocturnal hypertension, they did not meaningfully change the overall prevalence of INH.
Instead, the principal effect was a shift in which individuals were classified as having isolated nocturnal or sustained hypertension.
Further research is needed to determine whether these classification differences translate into meaningful differences in cardiovascular risk or clinical outcomes.
Reference
Gaston EW et al. Isolated nocturnal hypertension in type 2 diabetes: Impact of different ambulatory blood pressure thresholds on prevalence and reclassification. Diab Metab Synd. 2026.
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