Seasonal variation in nocturnal home blood pressure fall: the Nagahama study

Sleep blood pressure measured using a home blood pressure monitor was independently associated with cardiovascular disease incidence: the Nagahama study

BACKGROUND

Nocturnal blood pressure (BP) is associated with cardiovascular disease independently of awake BP. However, nocturnal BP measured using an ambulatory monitoring device has limited reproducibility because it is a single-day measurement. We investigated the association between sleep BP measured on multiple days using a timer-equipped home BP monitor and cardiovascular diseases in a general population.

METHODS

The study population comprised 5814 community residents. Participants were required to sleep with wrapping cuffs on their upper arm and BP was measured automatically at 0 : 00, 2 : 00, and 4 : 00. Actigraph was used to determine BP measured during sleep. Participants were also measured home morning and evening BP manually using the same device.

RESULTS

During the 7.3-year mean follow-up period, we observed 117 cases of cardiovascular diseases. The association between sleep BP (per 10 mmHg hazard ratio = 1.31, P  < 0.001) and cardiovascular events remained significant (hazard ratio = 1.22, P  = 0.036) even after adjusting for office BP and confounding factors, such as sleep-disordered breathing. Individuals with sleep-only hypertension ( n  = 1047; hazard ratio = 2.23, P  = 0.005) had a significant cardiovascular risk. Daytime-only hypertension ( n  = 264; hazard ratio = 3.57, P  = 0.001) and combined sleep and daytime hypertension ( n  = 1216; hazard ratio = 3.69, P  < 0.001) was associated with cardiovascular events to the same extent. Sleep BP dipping was not identified as a significant determinant of cardiovascular events.

CONCLUSION

Sleep BP measured using a home BP monitor was independently associated with the incidence of cardiovascular disease in a general population.

Short-term exposures to temperature and risk of sudden cardiac death in women: A case-crossover analysis in the Nurses' Health Study

Background

Sudden cardiac death (SCD) is a major source of mortality and is the first manifestation of heart disease for most cases. Thus, there is a definite need to identify risk factors for SCD that can be modified on the population level. Short-term exposures to temperature have been implicated as a potential risk factor. Our objective was to determine if short-term temperature exposures were associated with increased risk of SCD in a US-based time-stratified case-crossover study.

Methods

A total of 465 cases of SCD were identified among participants of the prospective Nurses' Health Study (NHS). Control days were selected from all other matching days of the week within the same month as the case day. Average ambient temperature on the current day (Lag0) and preceding 27 days (Lags1-27) was determined at the residence level using 800-m resolution estimates. Conditional logistic distributed lag nonlinear models (DLNMs) were used to assess the relative risk (RR) of the full range of temperature exposures over the lag period.

Results

Warmer exposures in the days before event and colder temperatures 21-28 days prior were associated with increased risks of SCD. These results were driven by associations in regions other than the Northeast and among married women.

Conclusions

Both warm and cold ambient temperatures are suggestively associated with risks of SCD among middle-aged and older women living across the United States.

The Association Between Season and Hypertensive Disorders in Pregnancy: a Systematic Review and Meta-analysis

There is increasing and inconsistent evidence of a relationship between hypertensive disorders in pregnancy (HDPs) and season of delivery or conception. In this systematic review and meta-analysis, we assessed the association between season and HDPs. The review protocol was registered in PROSPERO (CRD42021285539). Four databases, the Cochrane Library, PubMed, EMBASE, and Web of Science, were searched until September 29th, 2021. Two authors extracted data independently and used the Newcastle-Ottawa quality assessment scale (NOS) to evaluate study quality. A random effects model and the Mantel-Haenszel method were used to calculate pooled Odds ratios (ORs) and 95% confidence intervals (95% CIs). Subgroup analyses and sensitivity analyses were performed to find the source of heterogeneity and Begg's funnel plot and Egger's test were used to check for the risk of publication bias. Finally, twenty articles were included in the systematic review, and 11 articles were included in the meta-analysis. The quantitative analysis of the association between delivery season and HDPs showed that the odds of HDPs was higher in women who delivered in winter than in those who delivered in summer (OR = 1.18, 95% CI 1.02-1.38, P < 0.001) and all other seasons (OR = 1.17, 95% CI 1.03-1.34, P < 0.001). In the qualitative analysis of the association between conception season and HDPs, four of seven studies suggested that women who conceived in summer had a higher risk of HDPs than those who conceived in other seasons. Based on the evidence to date, we found weakly positive relationships between HDPs and summer conception and winter delivery.

Seasonal Variation in Day-by-Day Home Blood Pressure Variability and Effect on Cardiovascular Disease Incidence

BACKGROUND

Although day-by-day home blood pressure (BP) variability (BPV) has been associated with cardiovascular disease (CVD) risk, it remains unclear whether this association differs from season to season. The present study aimed to assess seasonal variation in day-by-day home BP variability and its association with CVD risk.

METHODS

We analyzed the data from a nationwide, prospective observational study, the J-HOP study (Japan Morning Surge-Home Blood Pressure), in which 14 consecutive days of home BP monitoring were conducted. The values of SD (SD_{systolic BP [SBP]}), coefficient of variation_SBP, and average real variability_SBP of home SBP were used as indices of day-by-day home BPV.

RESULTS

Among 4231 participants (mean age, 64.9±10.9 years, 46.7% male, 91.5% hypertensives), all 3 day-by-day home BPV indices were lower in summer than winter after adjusting for confounding factors. In winter, SD_SBP, coefficient of variation_SBP, and average real variability_SBP were significantly associated with increased risk of CVD events (coronary artery disease, stroke, heart failure, and aortic dissection; adjusted hazard ratio [95%CI] per 1-SD of SD_SBP, 1.26 [1.02-1.54]; coefficient of variation_SBP, 1.24 [1.02-1.52]; average real variability_SBP, 1.44 [1.17-1.77]). These relationships were also observed in the analysis of quartiles of BPV parameters (adjusted hazard ratio [95%CI] compared to the first quartile, fourth quartile of SD_SBP 2.26 [1.06-4.85]; coefficient of variation_SBP 2.96 [1.43-6.15]; average real variability_SBP 2.73 [1.25-5.93]). In other seasons, however, there were no significant associations between day-by-day home BPV and CVD event risk.

CONCLUSIONS

Our findings indicate that day-by-day home BPV measured in winter is more strongly associated with future CVD incidence than that measured in other seasons.

Supraphysiological Role of Melatonin Over Vascular Dysfunction of Pregnancy, a New Therapeutic Agent?

Hypertension can be induced by the disruption of factors in blood pressure regulation. This includes several systems such as Neurohumoral, Renin-angiotensin-aldosterone, the Circadian clock, and melatonin production, which can induce elevation and non-dipping blood pressure. Melatonin has a supraphysiological role as a chronobiotic agent and modulates vascular system processes via pro/antiangiogenic factors, inflammation, the immune system, and oxidative stress regulation. An elevation of melatonin production is observed during pregnancy, modulating the placenta and fetus’s physiological functions. Their impairment production can induce temporal desynchronization of cell proliferation, differentiation, or invasion from trophoblast cells results in vascular insufficiencies, elevating the risk of poor fetal/placental development. Several genes are associated with vascular disease and hypertension during pregnancy via impaired inflammatory response, hypoxia, and oxidative stress, such as cytokines/chemokines IL-1β, IL-6, IL-8, and impairment expression in endothelial cells/VSMCs of HIF1α and eNOS genes. Pathological placentas showed differentially expressed genes (DEG), including vascular genes as CITED2, VEGF, PL-II, PIGF, sFLT-1, and sENG, oncogene JUNB, scaffolding protein CUL7, GPER1, and the pathways of SIRT/AMPK and MAPK/ERK. Additionally, we observed modification of subunits of NADPH oxidase and extracellular matrix elements, i.e., Glypican and Heparanase and KCa channel. Mothers with a low level of melatonin showed low production of proangiogenic factor VEGF, increasing the risk of preeclampsia, premature birth, and abortion. In contrast, melatonin supplementation can reduce systolic pressure, prevent oxidative stress, induce the activation of the antioxidants system, and lessen proteinuria and serum level of sFlt-1. Moreover, melatonin can repair the endothelial damage from preeclampsia at the placenta level, increasing PIGF, Nrf-2, HO-1 production and reducing critical markers of vascular injury during the pregnancy. Melatonin also restores the umbilical and uterine blood flow after oxidative stress and inhibits vascular inflammation and VCAM-1, Activin-A, and sEng production. The beneficial effects of melatonin over pathological pregnancies can be partially observed in normal pregnancies, suggesting the dual role of/over placental physiology could contribute to protection and have therapeutic applications in vascular pathologies of pregnancies in the future.

Seasonal variation in blood pressure: current evidence and recommendations for hypertension management

Blood pressure (BP) exhibits seasonal variation, with an elevation of daytime BP in winter and an elevation of nighttime BP in summer. The wintertime elevation of daytime BP is largely attributable to cold temperatures. The summertime elevation of nighttime BP is not due mainly to temperature; rather, it is considered to be related to physical discomfort and poor sleep quality due to the summer weather. The winter elevation of daytime BP is likely to be associated with the increased incidence of cardiovascular disease (CVD) events in winter compared to other seasons. The suppression of excess seasonal BP changes, especially the wintertime elevation of daytime BP and the summertime elevation of nighttime BP, would contribute to the prevention of CVD events. Herein, we review the literature on seasonal variations in BP, and we recommend the following measures for suppressing excess seasonal BP changes as part of a regimen to manage hypertension: (1) out-of-office BP monitoring, especially home BP measurements, throughout the year to evaluate seasonal variations in BP; (2) the early titration and tapering of antihypertensive medications before winter and summer; (3) the optimization of environmental factors such as room temperature and housing conditions; and (4) the use of information and communication technology-based medicine to evaluate seasonal variations in BP and provide early therapeutic intervention. Seasonal BP variations are an important treatment target for the prevention of CVD through the management of hypertension, and further research is necessary to clarify these variations.

Nighttime home blood pressure as a mediator of N-terminal pro-brain natriuretic peptide in cardiovascular events

We tested our hypothesis that the association between N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiovascular disease (CVD) events is mediated in part by a pathway of increased nighttime blood pressure (BP) that involves volume overload. We used the data from the Japan Morning Surge-Home Blood Pressure (J-HOP) Nocturnal BP Study, which targeted 2476 Japanese participants who had a history of or risk for CVD (mean age 63.8 ± 10.2 years), along with their measured nighttime BP values assessed by a home BP device (measured at 2:00, 3:00 and 4:00 a.m.) and NT-proBNP levels. At baseline, elevated daytime (average of morning and evening) and nighttime home systolic BP (SBP) were independently associated with log-transformed NT-proBNP levels after adjustment for cardiovascular risk factors. During a median follow-up of 7.2 years, 150 participants experienced a CVD event (62 stroke events and 88 coronary artery disease events). After adjustment for cardiovascular risk factors and nighttime SBP, increased log-transformed NT-proBNP levels were independently associated with CVD events (hazard ratio [HR] per 1 unit, 1.67; 95% confidence interval [CI]: 1.16-2.40). Elevated nighttime home SBP was also independently associated with CVD events after adjustment for cardiovascular risk and log-transformed NT-proBNP (HR per standard deviation, 1.22; 95% CI: 1.001-1.50). The percentage of the association between NT-proBNP and CVD events mediated by nighttime home SBP was 15%. Our findings indicate a physiological pathway in which increased nighttime SBP contributes to the impact of elevated NT-proBNP levels on the incidence of CVD.

Seasonal Variation in Masked Nocturnal Hypertension: The J-HOP Nocturnal Blood Pressure Study

BACKGROUND

Little is known about seasonal variation in nighttime blood pressure (BP) measured by a home device. In this cross-sectional study, we sought to assess seasonal variation in nighttime home BP using data from the nationwide, practice-based Japan Morning Surge-Home BP (J-HOP) Nocturnal BP study.

METHODS

In this study, 2,544 outpatients (mean age 63 years; hypertensives 92%) with cardiovascular risks underwent morning, evening, and nighttime home BP measurements (measured at 2:00, 3:00, and 4:00 am) using validated, automatic, and oscillometric home BP devices.

RESULTS

Our analysis showed that nighttime home systolic BP (SBP) was higher in summer than in other seasons (summer, 123.3 ± 14.6 mmHg vs. spring, 120.7 ± 14.8 mmHg; autumn, 121.1 ± 14.8 mmHg; winter, 119.3 ± 14.0 mmHg; all P<0.05). Moreover, we assessed seasonal variation in the prevalence of elevated nighttime home SBP (≥120 mmHg) in patients with non-elevated daytime home SBP (average of morning and evening home SBP <135 mmHg; n = 1,565), i.e., masked nocturnal hypertension, which was highest in summer (summer, 45.6% vs. spring, 27.2%; autumn, 28.8%; winter, 24.9%; all P<0.05). Even in intensively controlled morning home SBP (<125 mmHg), the prevalence of masked nocturnal hypertension was higher in summer (summer, 27.4% vs. spring, 14.2%; autumn, 8.9%; winter, 9.0%; all P<0.05). The urine albumin-creatinine ratio in patients with masked nocturnal hypertension tended to be higher than that in patients with non-elevated both daytime and nighttime SBP throughout each season.

CONCLUSIONS

The prevalence of masked nocturnal hypertension was higher in summer than other seasons and the difference proved to be clinically meaningful.

Clinical significance of nocturnal home blood pressure monitoring and nocturnal hypertension in Asia

Nocturnal home blood pressure (BP) monitoring has been used in clinical practice for ~20 years. The authors recently showed that nocturnal systolic BP (SBP) measured by a home BP monitoring (HBPM) device in a Japanese general practice population was a significant predictor of incident cardiovascular disease (CVD) events, independent of office and morning home SBP levels, and that masked nocturnal hypertension obtained by HBPM (defined as nocturnal home BP ≥ 120/70 mmHg and average morning and evening BP < 135/85 mmHg) was associated with an increased risk of CVD events compared with controlled BP (nocturnal home BP < 120/70 mmHg and average morning and evening BP < 135/85 mmHg). This evidence revealed that (a) it is feasible to use a nocturnal HBPM device for monitoring nocturnal BP levels, and (b) such a device may offer an alternative to ambulatory BP monitoring, which has been the gold standard for the measurement of nocturnal BP. However, many unresolved clinical problems remain, such as the measurement schedule and conditions for the use of nocturnal HBPM. Further investigation of the measurement of nocturnal BP using an HBPM device and assessments of the prognostic value are thus warranted. Asians are at high risk of developing nocturnal hypertension due to high salt sensitivity and salt intake, and the precise management of their nocturnal BP levels is important. Information and communication technology‐based monitoring devices are expected to facilitate the management of nocturnal hypertension in Asian populations.

Home blood pressure on winter mornings could be exaggerated: A comparison with summer mornings

PURPOSE

Self-measured blood pressure at home (HBP) is quite important for the management of hypertension. We hypothesized that winter HBP measured according to the recommendation of the guidelines, but not HBP measured inside bed before getting up, is elevated in response to cold ambient temperatures in winter. This study aimed to investigate differences in HBP measured before and after getting up in winter and summer.Methods: Hypertensive subjects whose blood pressure was stably controlled were enrolled (n = 46, 73 years). They were instructed to measure HBP while in bed just after waking (HBP-bed), in addition to the ordinary HBP measurement in the morning (HBP-morning) according to the guidelines. The mean value of HBP for 7 consecutive days before the day of a regular hospital visit was considered as the HBP of each subject, and characteristics of the winter and summer BPs were investigated.Results: HBP-morning was significantly higher (P < .001) in winter than in summer, but HBP-bed was lower in winter than in summer (P < .05). HBP-morning was significantly higher than HBP-bed in winter, while HBP-morning was not different from HBP-bed in summer, resulting in greater changes in HBP after getting up in winter than in summer (P < .0001). Changes in HBP after getting up were significantly correlated with serum creatinine levels and the urinary albumin-to-creatinine ratio.Conclusions: These findings imply that elevated HBP-morning in winter reflects the response of BP to cold after getting up. Seasonal profiles of HBPs before and after getting up should be noted in the management of hypertension.

The relationship between home blood pressure measurement and room temperature in a Japanese general population

Blood pressure (BP) is influenced by various factors, and it is known that temperature and BP have a negative relationship. However, few reports have examined the relationship between BP and temperature throughout the day in the same participant over time. Therefore, this study aimed to investigate the relationship between BP and temperature in the morning and evening in the same participants during a time period of ~1 year. In total, 401 participants, who participated in a community-based health checkup survey in Tarumizu, Japan, were enrolled. Five participants were excluded due to missing data. All participants measured their BP and the room temperature at home using a blood pressure monitor (HEM-9700T, OMRON Healthcare, Kyoto, Japan). The mean systolic BP (SBP) and diastolic BP (DBP) in the morning were significantly higher than the mean of the measurements taken in the evening (SBP: morning vs. evening 128 ± 15 mmHg vs. 122 ± 14 mmHg, P < 0.0001; DBP: morning vs. evening 77 ± 10 mmHg vs. 72 ± 8 mmHg, P < 0.0001). Using a linear mixed model with participants as a random effect, SBP and DBP were significantly associated with temperature in both the morning and evening. In the morning, in almost every month except July, a significant association between SBP and temperature was observed. However, there was a significant relationship between evening BP and temperature in all months. In conclusion, BP was significantly related to temperature in both the morning and evening during the year-long study. Furthermore, BP and temperature were significantly associated in all months except morning measurements in July.

Management of Hypertension in the Digital Era: Small Wearable Monitoring Devices for Remote Blood Pressure Monitoring

Out-of-office blood pressure measurement is an essential part of diagnosing and managing hypertension. In the era of advanced digital health information technology, the approach to achieving this is shifting from traditional methods (ambulatory and home blood pressure monitoring) to wearable devices and technology. Wearable blood pressure monitors allow frequent blood pressure measurements (ideally continuous beat-by-beat monitoring of blood pressure) with minimal stress on the patient. It is expected that wearable devices will dramatically change the quality of detection and management of hypertension by increasing the number of measurements in different situations, allowing accurate detection of phenotypes that have a negative impact on cardiovascular prognosis, such as masked hypertension and abnormal blood pressure variability. Frequent blood pressure measurements and the addition of new features such as monitoring of environmental conditions allows interpretation of blood pressure data in the context of daily stressors and different situations. This new digital approach to hypertension contributes to anticipation medicine, which refers to strategies designed to identify increasing risk and predict the onset of cardiovascular events based on a series of data collected over time, allowing proactive interventions to reduce risk. To achieve this, further research and validation is required to develop wearable blood pressure monitoring devices that provide the same accuracy as current approaches and can effectively contribute to personalized medicine.

Home device-monitored sleep blood pressure reflects large artery stiffness: the Nagahama study

BACKGROUND

High sleep blood pressure (BP) has been suggested to be an independent risk factor for cardiovascular outcomes. To assess the applicability of sleep BP measured using a timer-equipped home device, we investigated the association between home device-measured sleep BP and large artery stiffness.

METHODS

We performed a cross-sectional analysis of a dataset from the Nagahama study (N = 5916), a general population-based cohort study. Home morning BP and sleep BP were measured using a timer-equipped cuff-oscillometric device (HEM-7080IC). Office BP, carotid intima--media thickness (IMT), and brachial--ankle pulse wave velocity (baPWV) were measured at the follow-up investigation of the Nagahama study.

RESULTS

Sleep hypertension (SBP ≥120 mmHg and/or DBP ≥70 mmHg) was associated with the arterial parameters (IMT: β = 0.051, baPWV: β = 0.141, both P < 0.001) independently of morning hypertension (IMT: β = 0.093, baPWV: β = 0.216, both P < 0.001) irrespective of antihypertensive medication status. Individuals exhibiting isolated sleep hypertension (N = 801) had thicker IMT (0.69 ± 0.14 vs. 0.64 ± 0.13 mm, P = 0.017) and faster baPWV (1,299 ± 197 vs. 1,183 ± 178 cm/s, P < 0.001) than normotensives. A sleep SBP at least 110 mmHg and a sleep DBP at least 65 mmHg were identified as the lower threshold BP values for the association with arterial parameters.

CONCLUSION

Sleep BP measurement using a home device may be a simple way to assess cardiovascular risks overlooked by office and home morning BP measurements.

The influence of the ambient temperature on blood pressure and how it will affect the epidemiology of hypertension in Asia

Epidemiologic studies have consistently demonstrated an increased risk of cardiovascular disease during colder temperatures. Hemodynamic changes associated with cold temperature and an increase in thrombogenicity may both account for the increase in cardiovascular risk and mortality. Studies using both in-office and out-of-office BP measurements have consistently shown an elevation in BP during the colder seasons. The large difference in BP between cold and warm months may increase the incidence of hypertension and reduce the hypertension control rate, potentially resulting in increased cardiovascular risk, especially among those at risk of cardiovascular disease. The current trends in global warming and climate change may have a profound impact on the epidemiology of hypertension and cardiovascular disease, as changes in the climate may significantly affect both BP variability and cardiovascular disease, especially in those with high cardiovascular risk and the elderly. Furthermore, climate change could have a significant influence on hypertension in Asia, considering the unique characteristics of hypertensive patients in Asia. As an increase in ambient temperature decreases the mean daytime average and morning surge in BP, but increases the nocturnal BP, it is difficult to predict how environmental changes will affect the epidemiology and prognosis of hypertension in the Asian-Pacific region. However, these seasonal variations in BP could be minimized by adjusting the housing conditions and using anticipation medicine. In this review, we discuss the impact of seasonal variation in the ambient temperature on hypertension and cardiovascular disease and discuss how this may impact the epidemiology of hypertension and cardiovascular disease.

Blood Pressure Non-Dipping and Obstructive Sleep Apnea Syndrome: A Meta-Analysis

Aim: We examined the reduced blood pressure (BP) nocturnal fall in patients with obstructive sleep apnea (OSA) by a meta-analysis including studies that provided data on prevalence rates of non-dipping (ND) pattern during 24-h ambulatory blood pressure monitoring (ABPM). Design: The PubMed, OVID-MEDLINE, and Cochrane CENTRAL literature databases were searched for appropriate articles without temporal restriction up to April 2019 through focused and sensitive search methods. Studies were identified by crossing the search terms as follows: “obstructive sleep apnea”, “sleep quality”, “non dipping”, “reduced nocturnal BP fall”, “circadian BP variation”, “night-time BP”, and “ambulatory blood pressure monitoring”. Results: Meta-analysis included 1562 patients with OSA from different clinical settings and 957 non-OSA controls from 14 studies. ND pattern prevalence in patients with OSA widely varied among studies (36.0–90.0%). This was also the case for non-OSA controls (33.0% to 69.0%). Overall, the ND pattern, assessed as an event rate in the pooled OSA population, was 59.1% (confidence interval (CI): 52.0–65.0%). Meta-analysis of the seven studies comparing the prevalence of ND pattern in participants with OSA and controls showed that OSA entails a significantly increased risk of ND (Odds ratio (OR) = 1.47, CI: 1.07–1.89, p < 0.01). After the exclusion of patients with mild OSA, OR increased to 1.67 (CI: 1.21–2.28, p < 0.001). Conclusions: The present meta-analysis, extending previous information on the relationship between OSA and impaired BP dipping, based on single studies, suggests that this condition increases by approximately 1.5 times the likelihood of ND, which is a pattern associated with a greater cardiovascular risk than normal BP dipping.

Nocturia and increase in nocturnal blood pressure: the Nagahama study

OBJECTIVE

Abnormalities in circadian blood pressure (BP) variation, particularly increase in nocturnal BP, have been reported to be risk factors for cardiovascular disease, although the factors associated with BP abnormalities are not fully understood. This study aimed to clarify possible associations of sleep characteristics, including sleep fragmentation, sleep disordered breathing, and nocturia, with sleep BP by simultaneous multiday measurements.

METHODS

A cross-sectional study evaluated 5959 community participants having home-measured data on nocturnal BP change (sleep BP - awaking BP), sleep characteristics, and sleep disordered breathing. Sleep characteristics including the fragmentation index were assessed using wrist-wearable actigraphy, whereas sleep disordered breathing was assessed by 3% oxygen desaturation index obtained using a finger-type monitor. The number of nocturnal urinations was recorded in a sleep diary.

RESULTS

Mean nocturnal SBP change was -8.5 ± 7.9%. A 3% oxygen desaturation index was associated with the BP change independently of the basic covariates (β = 0.051, P = 0.001), although the association became insignificant (P = 0.196) after adjusting the fragmentation index (β = 0.105, P < 0.001). The association of the fragmentation index was also insignificant (P = 0.153) after adjusting measurement season (middle season: β = 0.163, P < 0.001; summer season: β = 0.249, P < 0.001). In contrast, the frequency of urination showed strong and independent association (β = 0.140, P < 0.001), with smaller nocturnal BP drop in participants with frequent urination.

CONCLUSION

Subjective sleep estimates and frequent nocturnal urination may represent a potential risk for circadian BP abnormalities.

Improved home BP profile with dapagliflozin is associated with amelioration of albuminuria in Japanese patients with diabetic nephropathy: the Yokohama add-on inhibitory efficacy of dapagliflozin on albuminuria in Japanese patients with type 2 diabetes study (Y-AIDA study)

Background

The Y-AIDA study was designed to investigate the renal- and home blood pressure (BP)-modulating effects of add-on dapagliflozin treatment in Japanese individuals with type 2 diabetes mellitus (T2DM) and albuminuria.

Methods

We conducted a prospective, multicenter, single-arm study. Eighty-six patients with T2DM, HbA1c 7.0–10.0%, estimated glomerular filtration rate (eGFR) ≥ 45 mL/min/1.73 m², and urine albumin-to-creatinine ratio (UACR) ≥ 30 mg/g creatinine (gCr) were enrolled, and 85 of these patients were administered add-on dapagliflozin for 24 weeks. The primary and key secondary endpoints were change from baseline in the natural logarithm of UACR over 24 weeks and change in home BP profile at week 24.

Results

Baseline median UACR was 181.5 mg/gCr (interquartile range 47.85, 638.0). Baseline morning, evening, and nocturnal home systolic/diastolic BP was 137.6/82.7 mmHg, 136.1/79.3 mmHg, and 125.4/74.1 mmHg, respectively. After 24 weeks, the logarithm of UACR decreased by 0.37 ± 0.73 (P < 0.001). In addition, changes in morning, evening, and nocturnal home BP from baseline were as follows: morning systolic/diastolic BP − 8.32 ± 11.42/− 4.18 ± 5.91 mmHg (both P < 0.001), evening systolic/diastolic BP − 9.57 ± 12.08/− 4.48 ± 6.45 mmHg (both P < 0.001), and nocturnal systolic/diastolic BP − 2.38 ± 7.82/− 1.17 ± 5.39 mmHg (P = 0.0079 for systolic BP, P = 0.0415 for diastolic BP). Furthermore, the reduction in UACR after 24 weeks significantly correlated with an improvement in home BP profile, but not with changes in other variables, including office BP. Multivariate linear regression analysis also revealed that the change in morning home systolic BP was a significant contributor to the change in log-UACR.

Conclusions

In Japanese patients with T2DM and diabetic nephropathy, dapagliflozin significantly improved albuminuria levels and the home BP profile. Improved morning home systolic BP was associated with albuminuria reduction.

Trial registration The study is registered at the UMIN Clinical Trials Registry (UMIN000018930; http://www.umin.ac.jp/ctr/index-j.htm). The study was conducted from July 1, 2015 to August 1, 2018.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0912-3) contains supplementary material, which is available to authorized users.

Association between sleep disturbance and nocturnal blood pressure profiles by a linear mixed model analysis: the Nagahama study

OBJECTIVES

We aimed to analyze associations of sleep disturbance, including sleep disordered breathing, sleep fragmentation, and sleep efficiency, with abnormal nocturnal blood pressure (BP) profiles that may be risk factors for adverse cardiovascular outcomes.

METHODS

The study included 5854 community residents with 20,725 multi-day measurements. Sleep fragmentation and efficiency were evaluated using a wrist-worn activity monitor. Sleep disordered breathing was assessed using the 3% oxygen desaturation index corrected for actigraphy-determined sleep duration. A timer-equipped standard cuff-oscillometric device was used for home and sleep BP monitoring.

RESULTS

Mean nocturnal systolic BP (SBP) change was -8.6 ± 9.7% (-11.1 ± 12.6 mmHg), and inter-day correlation coefficient of the nocturnal SBP change was 0.443. Results of a linear mixed model analysis using daily measured values identified lower sleep efficiency (coefficient = -0.130, p < 0.001) as a determinant for decreased nocturnal SBP dipping beyond the interday variations of these parameters. Number of nocturnal urinations was another strong determinant (coefficient = 1.191, p < 0.001), although the association of sleep efficiency was independent of nocturnal urination, awake SBP, and sleep disordered breathing (coefficient = -0.102, p < 0.001). Sleep efficiency was also independently associated with sleep SBP level (coefficient = -0.138, p < 0.001). Estimated differences in nocturnal SBP dipping and sleep SBP level as a function of the degree of sleep efficiency (less than 80%) reached 1.63% (1.09-2.17%) and 2.16 mmHg (1.49-2.82%), respectively.

CONCLUSION

More attention should be paid to sleep efficiency as a factor in maintaining circadian BP rhythm.

Characteristics of visit-to-visit blood pressure variability in hemodialysis patients

Visit-to-visit blood pressure variability (VVBPV) is an independent risk factor for cardiovascular morbidity and mortality in the general population. Hemodialysis (HD) patients have a poor prognosis due to an increased prevalence of cardiovascular disease. Intradialytic hypotension is associated with excess mortality, but whether VVBPV influences mortality is still unclear in HD patients. The present study aimed to investigate the characteristics of VVBPV in these patients. A total of 324 maintenance HD patients, who could be followed for 60 months, were recruited. We used variation independent of the mean (VIM) in pre-dialysis systolic blood pressure (pre-VIM-SBP) as an index of VVBPV. We investigated (1) the reproducibility of pre-VIM-SBP, (2) the relationship between pre-VIM-SBP and background factors, and (3) the association between pre-VIM-SBP and mortality. Pre-VIM-SBP showed significant reproducibility [intraclass correlation, 0.45 (P < 0.001)]. Higher pre-VIM-SBP was associated with less physical activity and worse left ventricular diastolic function. Higher pre-VIM-SBP was associated with a higher rate of cardiovascular deaths independent of other factors. These data suggest that VVBPV in HD patients is reproducible and associated with various background factors. VVBPV is independently correlated with cardiovascular mortality (hazard ratio: 1.166, 95% confidence interval: 1.030-1.320, P = 0.015). Further studies are necessary to confirm the mechanism of increased VVBPV and to clarify whether reducing VVBPV will improve the prognosis for HD patients.