Prevalence and characteristics of isolated nocturnal hypertension in the general population

Clinical Significance of Nocturnal Hypertension and Nighttime Blood Pressure Dipping in Hypertension

PURPOSE OF REVIEW

This narrative review article aims to discuss more recent evidence, current challenges, and future perspectives regarding the clinical importance of nocturnal hypertension and nighttime blood pressure dipping, with particular reference to diagnosis, prognostic value, and therapeutic approach.

RECENT FINDINGS

The importance of nighttime blood pressure and nighttime blood pressure dipping has been demonstrated in decades. Increased nighttime blood pressure has been acknowledged as an unfavorable clinical trait. However, more recent evidence suggests that the abolishment of normal circadian blood pressure rhythm is not always a solid predictor of adverse cardiovascular events and needs to be interpreted in the light of each patients' individual characteristics. Physicians treating hypertensive patients with adverse nighttime blood pressure profiles often face the dilemma of chronotherapy. This has been a blurred field for years, yet very recent evidence from appropriately designed studies attempts to shed light on this puzzling question. As 24-h ambulatory blood pressure monitoring is being increasingly recommended and applied in real-world practice for the diagnosis and monitoring of hypertension, information on nighttime blood pressure and nocturnal dipping profile is collected but is not always easy to interpret.

Isolated Nocturnal Hypertension in People Living With Human Immunodeficiency Virus: A Cross-Sectional Study

BACKGROUND

Nocturnal hypertension (NH) is a potent cardiovascular risk factor described frequently in people with HIV (PWH). Isolated NH (INH) is less well reported in PWH because of the need for ambulatory blood pressure monitoring (ABPM) in office normotensive patients. We aim to document the prevalence of NH and INH and the clinical factors associated with these phenotypes.

METHODS

Cross-sectional study from an HIV program in Argentina. Office and ABPM measurements, as well as clinical and laboratory exploration, were performed. We defined INH as NH with daytime normotension in patients with office normotension.

RESULTS

We obtained ABPM in 66 PWH, 60% male, aged 44.7 (IQR 27-69) years; 87% receiving antiretroviral therapy, and 86.2% virologically suppressed. ABPM-based hypertension prevalence was 54.7% (95% CI: 42.5-66.3). The prevalence of NH was 48.5% (32/66), while the INH prevalence was 19.7% (95% CI: 11.7-30.9). No differences were found regarding sex, HIV viral load, CD4+ T lymphocytes count, or years of infection between normotensive and INH patients. Multiple linear regression model adjusted for sex and age determined that body mass index (β = 0.93, P < 0.01), plasma uric acid (β = 0.25, P = 0.04), plasma potassium (β = -10.1, P = 0.01), and high-sensitivity C-reactive protein (hs-CRP) (β = 0.78, P = 0.02) independently predicted nocturnal systolic blood pressure (BP) in PWH. In a multiple logistic regression model adjusted for age and sex, the presence of sedentariness, plasma potassium <4 mEq/L, BMI, and hs-CRP levels were predictors of INH.

CONCLUSION

INH is highly prevalent in PWH. Metabolic and inflammatory markers predict nocturnal SBP in PWH.

Non-Dipping Blood Pressure or Nocturnal Hypertension: Does One Matter More?

PURPOSE OF REVIEW

Nocturnal hypertension and non-dipping are both associated with increased cardiovascular risk; however, debate remains over which is a better prognosticator of cardiovascular outcomes. This review explores current literature on nocturnal hypertension and non-dipping to assess their relationship to cardiovascular disease and implications for clinical practice.

RECENT FINDINGS

While current data remain inconclusive, some suggest that nocturnal hypertension is a more reliable and clinically significant marker of cardiovascular risk than non-dipping status. Importantly, reducing nocturnal HTN and non-dipping through chronotherapy, specifically evening dosing of antihypertensives, has not been conclusively shown to provide long-term cardiovascular benefits. Recent data suggests that non-dipping, compared to nocturnal hypertension, may be falling out of favor as a prognostic indicator for adverse cardiovascular outcomes. However, additional information is needed to understand how aberrant nighttime blood pressure patterns modulate cardiovascular risk to guide clinical management.

Prevalence and Characteristics of Isolated Nocturnal Hypertension and Masked Nocturnal Hypertension in a Tertiary Hospital in the City of Buenos Aires

Isolated nocturnal hypertension (INH) and masked nocturnal hypertension (MNH) increase cardiovascular risk. Their prevalence and characteristics are not clearly established and seem to differ among populations. We aimed to determine the prevalence and associated characteristics of INH and MNH in a tertiary hospital in the city of Buenos Aires. We included 958 hypertensive patients ≥ 18 years who underwent an ambulatory blood pressure monitoring (ABPM) between October and November 2022, as prescribed by their treating physician to diagnose or to assess hypertension control. INH was defined as nighttime BP ≥ 120 mmHg systolic or ≥70 diastolic in the presence of normal daytime BP (<135/85 mmHg regardless of office BP; MNH was defined as the presence of INH with office BP < 140/90 mmHg). Variables associated with INH and MNH were analyzed. The prevalences of INH and MNH were 15.7% (95% CI 13.5-18.2%) and 9.7 (95% CI 7.9-11.8%), respectively. Age, male sex, and ambulatory heart rate were positively associated with INH, whereas office BP, total cholesterol, and smoking habits showed a negative association. In turn, diabetes and nighttime heart rate were positively associated with MNH. In conclusion, INH and MNH are frequent entities, and determination of clinical characteristics such as those detected in this study is critical since this might contribute to a more appropriate use of resources.

Isolated nocturnal hypertension in relation to host and environmental factors and clock genes

Isolated nocturnal hypertension (INH) is a special type of out-of-office hypertension. Its determinants and pathophysiology remain unclear. In a nested case-control study, we intend to investigate the host, environmental, and genetic factors in relation to INH. Among 2030 outpatients screened from December 2008 till June 2015, 128 patients with INH were identified, and then 128 normotensives were matched according to sex and age. INH was an elevated nocturnal blood pressure (BP ≥120/70 mmHg) in the presence of a normal daytime BP (< 135/85 mmHg). Host factors included age, sex, body mass index, smoking and drinking, sleep time and duration, heart rate, serum lipids, and serum creatinine. Environmental cues encompassed season, ambient temperature, atmospheric pressure, humidity, and wind speed, and genetic cues 29 single-nucleotide polymorphisms (SNPs) in 12 clock genes. Daytime and nighttime BPs averaged 124.9/80.7  and 114.5/73.7 mmHg, respectively, in the INH patients and 121.0/76.5 and 101.8/63.3 mmHg in the normotensive controls. Stepwise logistic regression analyses revealed that INH was associated with nighttime heart rate (P = .0018), sleep duration (P = .0499), and relative humidity (P = .0747). The odds ratios (95% CI) for each 10 beats/min faster nighttime heart rate and 10% lower relative humidity were 1.82 (1.25-2.65) and 0.82 (0.67-1.00), respectively. Irrespective of the genetic models, no significant association was observed between INH and the SNPs (P ≥ .054). In conclusion, INH was associated with host and environmental factors rather than genetic markers.

Isolated Nocturnal Hypertension in Children

Isolated nocturnal hypertension (INH) is attracting attention because it has been shown to correlate with target organ damage as well as cardiovascular events in adults. INH has also been reported in children especially in those with underlying diseases including chronic kidney disease and some studies reported association with markers of early target organ damage. INH occupies the majority of nocturnal hypertension. On the other hand, masked hypertension is largely attributed to INH. INH is usually diagnosed by ambulatory blood pressure monitoring. Recently, it became possible to monitor sleep blood pressure by an automated home blood pressure device feasible also in children. The epidemiology, methodology and reproducibility, pathophysiology, relation to target organ damage, and treatment of INH in children will be reviewed here along with adult data.