The relationship between red blood cell distribution width and blood pressure abnormal dipping in patients with essential hypertension: a cross-sectional study

Association between red cell distribution width and hypertension: Results from NHANES 1999-2018

The relationship between red cell distribution width (RDW) and hypertension remains a contentious topic, with a lack of large-scale studies focusing on the adults in the United States. This study aimed to investigate the association between RDW and hypertension among US adults from 1999 to 2018.

METHODS

Data were derived from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. RDW values were obtained from the Laboratory Data's Complete Blood Count with 5-part Differential-Whole Blood module. Hypertension data were obtained through hypertension questionnaires and blood pressure measurements. Multivariable weighted logistic regression analyses were conducted to assess the association between RDW and hypertension, followed by subgroup and smooth curve analyses.

RESULTS

Compared to the non-hypertensive group, the hypertensive group exhibited higher RDW values (13.33±1.38 vs. 12.95±1.27, P <0.001). After adjusting for covariates, weighted multivariable logistic regression analysis revealed a positive correlation between RDW and hypertension prevalence (OR: 1.17, 95% CI 1.13, 1.21, P <0.001). When RDW was included as a categorical variable, participants in the fourth quartile had the highest risk of hypertension (OR: 1.86, 95% CI 1.70, 2.03, P <0.001). Subgroup analysis showed that, except for age, BMI and weak/failing kidneys, gender, race, education level, smoking, alcohol use, congestive heart failure, and stroke did not significantly influence this correlation (all P-values for interaction >0.05).Smooth curve fitting analysis revealed a reverse J-shaped relationship between RDW and hypertension prevalence, with an inflection point at 12.93%.

CONCLUSION

We first explored the relationship between RDW and hypertension among US adults and discovered a reverse J-shaped association, providing further insights into the relationship between blood cell counts and hypertension and offering a new foundation for hypertension prevention and control.

The association between red cell distribution width and newly diagnosed hypertension among adults in Northern Sudan: a case-control study

The existing data have shown inconsistency about the association between red cell distribution width (RDW) and hypertension. Thus, the aim of the present study was to investigate the association between RDW and newly diagnosed hypertension among adults in Sudan. This was a case-control study conducted in Northern Sudan from July to September 2022. The cases were patients with newly diagnosed hypertension (n = 78), and the controls were healthy participants (n = 78). A questionnaire was used to collect the participants' sociodemographic, and clinical data. RDW was measured using an automated hematology analyzer. A logistic regression analysis was performed. The univariate analysis revealed no association between sex, educational level, occupational level, RDW, and newly diagnosed hypertension. In the multivariate analysis, increasing age (adjusted odds ratio [AOR], 1.05; 95% confidence interval [CI], 1.02‒1.08) and body mass index (AOR, 1.12; 95% CI, 1.05‒1.19) were associated with newly diagnosed hypertension. No association was found between RDW and newly diagnosed hypertension. No correlation was found between RDW and systolic (r = 0.045, P = 0.577) or diastolic blood pressure (r = 0.023, P = 0.772). In conclusion, no association in RDW was found between the patients with newly diagnosed hypertension and the healthy controls.

The Predictive Role of Hematological Parameters in Hypertension

Hypertension (HT) is a common chronic disease that often causes target-organ damage and severe complications, contributing to cardiovascular morbidity and mortality worldwide. Accumulating evidence suggests that inflammation plays a prominent role in the initiation and progression of HT. Multiple inflammatory biomarkers have been proposed to predict HT. Several new hematological parameters can reflect the inflammatory response and platelet activation. The major advantage of hematological parameters over conventional inflammatory markers is that they are relatively inexpensive and easily obtained from routine blood tests. Numerous studies have investigated several hematological parameters for their utility as predictive biomarkers for the diagnosis and prognosis of HT. Among them, the neutrophil to lymphocyte ratio (NLR), monocyte to high density lipoprotein cholesterol ratio (MHR), red cell distribution width (RDW), platelet to lymphocyte ratio (PLR), mean platelet volume (MPV), platelet distribution width (PDW), and systemic immune-inflammation index (SII) have recently received attention. We searched PubMed and Embase databases (up to September 18, 2022) to assess the relationships between hematological parameters and HT. This review discusses the diagnostic and prognostic value of these hematological parameters in HT, providing an important basis for early screening, risk stratification, and optimal management of hypertensive patients.

Effects of Nondipping Blood Pressure Changes: A Nephrologist Prospect

Blood pressure (BP) variations depend on various internal, environmental, and behavioral factors. BP fluctuations occur both in normotensive and hypertensive people. Although it fluctuates over the 24-hr day and night, the morning BP increases after waking up and declines throughout sleep. It is typical for BP to decrease by 10% to 20%, while sleeping, known as dipping BP. However, if there is no decrease in nighttime mean systolic BP or a drop of less than 10 mmHg, it is called nondipping BP. Conversely, reverse dipping BP means an increase in mean systolic BP instead of a drop during the night. Reverse dipping is observed in hypertension (HTN), diabetes mellitus (DM), chronic kidney disease (CKD), and obstructive sleep apnea (OSA) syndrome. The introduction of ambulatory BP monitoring (ABPM) led to the emergence of identifying normal and elevated BP patterns. Non-dipping BP increases the risk of cardiovascular system (CVS) complications such as left ventricular hypertrophy, proteinuria, glomerular filtration rate (GFR) reduction, and CKD progression. A loss or blunting of the normal BP profile is recognized as a deleterious variant, and restoring abnormal BP patterns has been reported to significantly impact end-organ damage, morbidity, and mortality. In this non-systematic clinically-oriented, comprehensive review, we aim to update the BP variables and the pathophysiology of nondipping BP and point out the areas which need more investigation from a nephrology perspective because the nondipping BP increases the risk of proteinuria, GFR reduction, and CKD progression. A literature search of PubMed, Google, EMBASE, and Google Scholar was conducted. Checks of selected papers and relevant reviews complemented the electronic search. With improved BP measurement methods, the physiology of BP profile variations is readily detectable during the day and night. A nondipping BP profile is a distinct BP pattern that may have significant end-organ damage effects and therapeutic importance for nephrologists. The pathophysiology of the nondipping BP variant must be clarified to prevent complications, and further investigations are required. Furthermore, there is debate about the best BP index to utilize: systolic BP, diastolic BP, mean arterial pressure, or a mixture of all. All these areas are important and need new research projects.

Role of sympathetic pathway in light-phase time-restricted feeding-induced blood pressure circadian rhythm alteration

Disruption of blood pressure (BP) circadian rhythm, independent of hypertension, is emerging as an index for future target organ damage and is associated with a higher risk of cardiovascular events. Previous studies showed that changing food availability time alters BP rhythm in several mammalian species. However, the underlying mechanisms remain largely unknown. To address this, the current study specifically investigates (1) the relationship between rhythms of food intake and BP in wild-type mice; (2) effects of light-phase time-restricted feeding (TRF, food only available during light-phase) on BP circadian rhythm in wild-type and diabetic db/db mice; (3) the roles of the autonomic system and clock gene in light-phase TRF induced changes in BP circadian rhythm. Food intake and BP of C57BL/6J and db/db mice were simultaneously and continuously recorded using BioDAQ and telemetry systems under ad libitum or light-phase TRF. Per2 protein daily oscillation was recorded in vivo by IVIS spectrum in mPer2 Luc mice. Autonomic nerve activity was evaluated by heart rate variability, baroreflex, urinary norepinephrine (NE) and epinephrine (Epi) excretion, and mRNA expressions of catecholamines biosynthetic and catabolic enzymes, and alpha-adrenergic receptors in mesenteric resistance arteries. We found that in wild-type mice, the BP level was correlated with the food intake temporally across the 24 h. Reversing the feeding time by imposing light-phase TRF resulted in reverse or inverted BP dipping. Interestingly, the net changes in food intake were correlated with the net alteration in BP temporally under light-phase TRF. In db/db mice, light-phase TRF worsened the existing non-dipping BP. The food intake and BP circadian rhythm changes were associated with alterations in Per2 protein daily oscillation and the time-of-day variations in heart rate variability, baroreflex, and urinary excretion of NE and Epi, and increased mRNA expression of Slc6a2 (encoding NE transporter) and Adra1d (encoding alpha-adrenergic receptor 1d) in the mesenteric resistance arteries, indicating the sympathetic nervous system (SNS) was modulated after light-phase TRF. Collectively, our results demonstrated that light-phase TRF results in reverse dipping of BP in wild-type and diabetic db/db mice and revealed the potential role of the sympathetic pathway in light-phase TRF-induced BP circadian rhythm alteration.

Prognostic significance of reverse dipping status on lower limb event in type 2 diabetic patients without peripheral arterial disease

AIMS

We assessed reverse dipping influence on the risk of lower limb events in type 2 diabetic patients without peripheral arterial disease.

METHODS

Patients with type 2 diabetes addressed for cardiovascular risk stratification in our university hospital from 2008 to 2012 underwent 24 h blood pressure monitoring. Patients with a prior history of limb revascularization or with a stenosis > 50% of the legs were excluded. Reverse dipping was defined as a greater night-versus day-time systolic blood pressure. The endpoint was the first occurrence of lower limb revascularization or limb amputation. Hazard ratios (HRs) and 95% confidence intervals were calculated using the Cox model.

RESULTS

Two hundred and eighty-one patients were included. During a median follow-up of 9.4 [7.7-10.6] years, 20 lower limb events and 45 all-cause deaths were observed. Thirty-five patients were reverse dippers. The reverse dipping status was associated with lower limb events when considering all-cause death as a competitive risk, (HR 3.61 [1.16-11.2], P = 0.026). Reverse dipping, HbA1C and proteinuria were independently associated with lower limb outcome in a multivariable analysis (respectively HR 4.09 [1.29-12.9], P = 0.017, HR 1.30 [1.04-1.63], P = 0.022 and HR 1.06 [1.02-1.11], P = 0.001).

CONCLUSIONS

Reverse dipping status is independently associated with worse limb outcome in type 2 diabetic patients.

Inflammation and Arterial Hypertension-Pathophysiological Links and Clinical Aspects

Arterial hypertension represents one of the most common pathologies in the adult population. Hypertensive patients have structurally altered arteries, with a higher rigidity that leads to a significant decrease in vascular compliance. At the base of the pathophysiological process stands the inflammation, as a reaction of the organism to injury.

OBJECTIVES

This study aims to highlight clinical-paraclinical correlations in people diagnosed with arterial hypertension and inflammatory status. Thus, we would like to evaluate possible correlations between the usual inflammatory markers and blood pressure values.

MATERIALS AND METHODS

The sample comprises 64 adults who were subsequently divided based on the diagnosis of arterial hypertension, by using Automatic Blood Pressure Monitoring, as following: Study group=26 patients (with arterial hypertension) and Control group: 38 patients (without arterial hypertension).

RESULTS

The study has revealed negative correlations between the neutrophil/lymphocyte ratio (NLR) and the general diastolic average (r=-0.248 and p=0.047), the diurnal diastolic average (r=-0.258 and p=0.038) and the diurnal mean arterial pressure (r=-0.249 and p=0.046) and a negative correlation between the red cell distribution width (RDW) and the dipping index (r=-0.402 and p=0.013), each of them accomplishing the level of statistical significance.

CONCLUSIONS

NLR can be used as a predictor of diastolic blood pressure values and as a factor of prognosis for the evolution of arterial hypertension. RDW is higher in non-dipping patients.

Aging and Vascular Compliance in Hypertensive Patients Mirrored in Routine Investigations

The global prevalence of arterial hypertension is increasing. Due to its consequences, hypertension is a leading cause of morbidity /mortality. In this regard, awareness of the importance of diagnosis as well as proper treatment of hypertension is mandatory.

OBJECTIVES

This study aims to analyze vascular compliance and different pressure characteristics depending on age, along with highlighting some clinical-paraclinical correlations in people diagnosed with hypertension. We used usual laboratory analyzes and the blood pressure values obtained using ABPM/24 hr, in addition to highlighting the impact of age on those parameters.

MATERIALS AND METHODS

The sample comprises of 99 adults diagnosed with hypertension. We divided them into 2 groups, according to age: cases sample: 52 patients (age> 60 years old) and control sample: 47 patients (age< 60 years old).

RESULTS

In the control group, RDW was correlated with the general and diurnal systolic and diastolic hypertonicity indexes and the platelet count was positively correlated only with the morning surge. The dipping profile correlates negatively with RDW. In the elderly, all three systolic blood pressure parameters are influenced by ESR and also correlate negatively with HDL, with an inverse proportional relationship. Statistically significant correlations were found between blood glucose and diurnal systolic and diastolic hypertonicity indexes. Mean Pulse Pressure correlates in the elderly with HDL (negative correlations) and in the young with RDW (positive correlations).

CONCLUSIONS

Vascular compliance can be estimated with the help of HDL in the elderly and RDW in young people, considering the influence of the two parameters on pulse pressure.

Association between ambulatory blood pressure variability and frailty among older hypertensive patients

Frailty and hypertension often coexist and are increasingly prevalent with advancing age. Although hypertension is independently associated with frailty, whether high blood pressure variability affecting frailty is unclear. In this retrospective study, we consecutively enrolled elderly patients with essential hypertension undergoing 24-hour ABPM. The frailty was assessed by a 38-item frailty index. The parameters of blood pressure variability of ABPM, including ARV, coefficient of CV, SD, and weighed SD were calculated. Ordinal logistic regression was used to investigate the association between blood pressure variability and frailty. A total of 242 hypertensive patients were recruited and divided into the frail group, pre-frail group, and non-frail group. The overall magnitudes of BP variability, assessed by ARV, CV, SD, and weighed SD, were significantly greater in patients with frailty than those with pre-frailty and non-frailty. With adjustment for covariates, ARV of 24-hour, diurnal, and nocturnal SBP were independently associated with frailty (24 hours, OR: 2.48, 95% CI: 2.01-3.07; daytime, OR: 1.83, 95% CI: 1.60-2.10; nighttime, OR: 1.19, 95% CI: 1.12-1.27). The CV of 24-hour, diurnal, and nocturnal SBP was independently associated with frailty in the study (24 hours, OR: 1.2, 95% CI: 1.05-3.07; daytime, OR: 1.19, 95% CI: 1.05-1.34; nighttime, OR: 1.13, 95% CI: 1.03-1.24). For SD and weighed SD, only 24-hour systolic SD was independent risk factor associated with frailty (OR: 1.12, 95% CI: 1.01-1.23). The greater blood pressure variability of SBP, particular ARV and CV, were independent risk factors associated with higher-order frailty status. Longitudinal studies are needed to investigate the causality associations between hypertension and frailty.

Circadian Blood Pressure Variations Computed From 1.7 Million Measurements in an Acute Hospital Setting

BACKGROUND

Knowledge of the circadian blood pressure (BP) variations in the acute hospital setting is very limited.

METHODS

This is a retrospective analysis of BP data for in-hospital patients stratified by age and sex. We used data collected with the help of a standardized electronic health record system between March 2014 and April 2018 on the adult general wards in 4 acute hospitals in Oxford, UK.

RESULTS

A total of 41,455 unique patient admissions with 1.7 million sets of vital-sign measurements have been included in the study. The typical 24-hour systolic BP profile (dipping pattern during sleep followed by a gradual increase during the day) was only seen in the younger age groups (up to 40–49 for men and 30–39 for women). For older age groups, there was a late nocturnal rise in systolic BP, the amplitude of which increased with age. The late nocturnal BP rise above the age of 50 was seen whether or not the patient was treated for or previously identified with hypertension.

CONCLUSION

Hospitalized patients’ circadian patterns of BP largely mirror those found in the community. High-quality hospital data may allow for the identification of patients at significant cardiovascular risk through either opportunistic screening or systematic screening.

The role of red blood cell distribution width (RDW) in cardiovascular risk assessment: useful or hype?

Red blood cell distribution width (RDW) reflects erythrocyte size distribution, thus representing a reliable index of anisocytosis, widely used for the differential diagnosis of micro- and normocytic anaemias. Along with the large use in diagnostic hematology, RDW has been associated with presence and complications of a vast array of human pathologies during the last decades, including cardiovascular (CV) diseases. This article is hence aimed to provide an overview of important studies and systematic reviews with meta-analysis, in which RDW has been associated with CV events and mortality, in the attempt of establishing whether enough evidence exists for supporting its routine use in clinical practice. According to available data it seems reasonable to conclude that although the diagnostic specificity is low, and this measure is still plagued by important lack of standardization, RDW can be regarded as an index of enhanced patient fragility and higher vulnerability to adverse outcomes. Abnormal RDW values shall hence persuade physicians to broaden the diagnostic reasoning over anaemias, especially those due to malnutrition or malabsorption, encompassing a comprehensive assessment of traditional and non-traditional CV risk factors.

Inverted U-shaped curve relationship between red blood cell distribution width and hypertension in a large health checkup population in China

This study was aimed at investigating the relationship between red blood cell distribution width (RDW) and hypertension in a large health check up population in China. A population of 302,527 subjects from Wuhu was enrolled in this cross-sectional health check up study between 2011 and 2016. They consisted of 126,369 women (41.78%) and 176,158 men (58.23%) with mean age of 46.9 ± 13.4 and 48.1 ± 13.7 years, respectively. The investigations included information on demographic characteristics, physical examination, and laboratory testing. Inverted U-shape relationships were observed between RDW and hypertension with peak RDW values of 14.2 (women) and 15.2 (men). After stratification by sex and adjusted with body mass index, age, white blood cells, and high-density lipoprotein cholesterol, inverted U-shape relationships were also established between RDW and hypertension, systolic blood pressure, and diastolic blood pressure, with peak RDW of 14.2, 14.5, 14.5 in women and 14.2, 16.0, 14.5 in men. Inverted U-shape relationship exists between RDW and hypertension, systolic blood pressure, and diastolic blood pressure among the Chinese health check up population studied.

Red cell distribution width associated with adverse cardiovascular outcomes in patients with chronic kidney disease

Background

Recent studies have demonstrated that red cell distribution width (RDW) is associated with cardiovascular (CV) events and mortality. Patients with chronic kidney disease (CKD) are often anemic and have high RDW levels. In this study, we investigated the effect of RDW on major composite CV outcomes among patients with CKD.

Methods

We retrospectively analyzed patients with CKD who were admitted to the department of cardiology of a tertiary hospital in 2011. The patients were divided into 2 groups: normal RDW (RDW < 14.5%) and elevated RDW (RDW ≥ 14.5%). Demographic characteristics, comorbidities, blood investigation results, prescriptions, and outcomes were analyzed after a 3-year follow-up period. Six adjustment levels were performed to evaluate the effect of RDW on outcomes.

Results

This study involved 282 patients with CKD: 213 in the elevated RDW group and 69 in the normal RDW group. The elevated RDW group had older patients, a lower proportion of male patients, lower left ventricular ejection fraction (LVEF) values, lower hemoglobin levels, lower serum albumin levels, and higher creatinine levels, compared with the normal RDW group. A linear trend was observed toward higher RDW in patients with deteriorating renal function. In the final adjusted model, RDW ≥ 14.5%, older age, and lower LVEF were associated with an increased risk of major composite CV outcomes.

Conclusion

RDW is a potentially useful cost-effective indicator of major composite CV outcomes in patients with CKD.

Red Blood Cell Distribution Width: A Novel Predictive Indicator for Cardiovascular and Cerebrovascular Diseases

The red blood cell distribution width (RDW) obtained from a standard complete blood count (CBC) is a convenient and inexpensive biochemical parameter representing the variability in size of circulating erythrocytes. Over the past few decades, RDW with mean corpuscular volume (MCV) has been used to identify quite a few hematological system diseases including iron-deficiency anemia and bone marrow dysfunction. In recent years, many clinical studies have proved that the alterations of RDW levels may be associated with the incidence and prognosis in many cardiovascular and cerebrovascular diseases (CVDs). Therefore, early detection and intervention in time of these vascular diseases is critical for delaying their progression. RDW as a new predictive marker and an independent risk factor plays a significant role in assessing the severity and progression of CVDs. However, the mechanisms of the association between RDW and the prognosis of CVDs remain unclear. In this review, we will provide an overview of the representative literatures concerning hypothetical and potential epidemiological associations between RDW and CVDs and discuss the underlying mechanisms.

Clinical and prognostic significance of a reverse dipping pattern on ambulatory monitoring: An updated review

Reverse or inverted dipping (ie, the phenomenon characterized by higher nighttime compared with daytime blood pressure values) is an alteration of circadian blood pressure rhythm frequently documented in hypertension, type 2 diabetes mellitus, chronic kidney disease, and sleep apnea syndrome, and generally regarded as a harmful condition. Available literature on the clinical and prognostic implications of reverse dipping is scanty. The present article will review a number of relevant issues concerning reverse dipping, in particular: (1) its possible mechanisms; (2) prevalence and clinical correlates, (3) concomitant cardiac and extracardiac subclinical organ damage; (4) association with acute and chronic cardiovascular diseases; (5) prognostic value in predicting cardiovascular events and mortality; and (6) therapeutic interventions aimed at reverting this abnormal circadian blood pressure rhythm.

Importance of Mean Red Cell Distribution Width in Hypertensive Patients

PURPOSE

Red cell distribution width (RDW), expressed in femtoliters (fl), is a measure of the variation in the size of circulating erythrocytes and is often expressed as a direct measurement of the width of the distribution. We aim to observe the mean value of red cell distribution width (RDW) in hypertensive patients. Increased RDW can be used as a tool for early diagnosis, as an inflammatory marker, and a mortality indicator in hypertensive patients due to its close relation to inflammation.

MATERIALS AND METHODOLOGY

Hypertensive patients who had the condition for more than one year duration, diagnosed according to the Joint National Committee (JNC 7) criteria were subjected to complete blood count and RDW measurement. One hundred patients, aged between 12 years and 65 years were enrolled from the outpatient department of medicine at the Military Hospital Rawalpindi.

RESULTS

The mean age (± SD) of the patients was 51.48 ± 10.08 years. Out of 100 patients 69% were males whereas 31% were females. The overall frequency of hypertension more than five years was 55% subjects whereas 45% individuals had duration of hypertension less than five years. Mean RDW in females was found to be 49.35±8.42 fl while mean RDW in males was 44.78±7.11 fl. An independent sample t-test was applied to assess if there was any significant difference between age and gender. No significant difference between age and gender was found (p<0.05). The Mann-Whitney test was used to assess any association of RDW with gender. RDW values in females was found to be statistically significantly higher than in males (U=603, p=0.01). Linear regression showed that mean RDW value increased with increasing age (P <0.001).

CONCLUSIONS

A significant number of patients with hypertension have increased levels of RDW. Therefore, it is recommended that serum RDW should be checked regularly in patients with hypertension.