Masked uncontrolled hypertension in patients with end-stage kidney disease on in-center hemodialysis

Masked uncontrolled hypertension (MUCH) is associated with an increasing risk of morbidity and mortality. Current literature on MUCH lacks data on patients with end-stage kidney disease (ESKD) on hemodialysis (HD). We aimed to investigate the prevalence, ambulatory blood pressure (BP) characteristics, and risk factors of MUCH in this population in a low-middle-income Asian country.

We conducted a simple random-sampling, cross-sectional study on patients with hypertension and ESKD on HD. The outcome was MUCH, which was confirmed if the participants, who were on 24-hour ambulatory BP monitoring, had at least 1 of the following criteria: (1) daytime mean ambulatory BP ≥ 135 mmHg (systolic) and/or ≥ 85 mmHg (diastolic); (2) night-time mean ambulatory BP ≥ 120 mmHg (systolic) and/or ≥ 70 mmHg (diastolic); or (3) 24-hour mean ambulatory BP ≥ 130 mmHg (systolic) and/or ≥ 80 mmHg (diastolic). Data were presented using descriptive statistics. We used logistic regression to explore the risk factors for MUCH, and the results were reported with odds ratio (OR) and 95% confidence interval (95% CI).

Among 104 participants included for analysis (median age 54.5, 48.1% being female), MUCH was reported on 85 of them (prevalence of 81.7%, 95% CI 73.2-88.0%.). Non-dipping status of BP were found in 98.1% of the participants, with non-dippers dominating the normotension group (prevalence of 57.9%, 95% CI 36.3-76.9%) and reverse dippers dominating the MUCH group (prevalence of 65.9%, 95% CI 55.3-75.1%). We also identified some factors that were associated with a higher risk of MUCH, i.e., being current smoker (adjusted OR = 3.49, 95% CI 1.07 to 11.40), undergoing HD for > 48 months (adjusted OR = 5.69, 95% CI 1.48 to 21.81), taking > 3 antihypertensive medications (adjusted OR = 3.64, 95% CI 1.11 to 11.92), and requiring α2-adrenergic receptor agonists for BP control (adjusted OR = 6.31, 95% CI 1.12 to 35.62).

The prevalences of MUCH and non-dipping of BP (non-dipper and reverse dipper) were very high in patients with ESKD who were undergoing HD for a median duration of 6 years without ambulatory BP monitoring. To avoid extra cost and inconvenience, risk factors should be initially screened for MUCH before monitoring out-of-office BP for a confirmed diagnosis.