Seasonal variation in meteorological parameters and office, ambulatory and home blood pressure: predicting factors and clinical implications

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.

Seasonal variation in ambulatory blood pressure control in patients on clinic blood pressure-guided antihypertensive treatment

BACKGROUND

We investigated seasonal variation in ambulatory blood pressure control in hypertensive patients on clinic blood pressure-guided antihypertensive treatment.

METHODS

The study participants were hypertensive patients enrolled in an 8-week therapeutic study. Antihypertensive treatment was initiated with long-acting dihydropyridine calcium channel blockers amlodipine 5 mg/day or the gastrointestinal therapeutic system (GITS) formulation of nifedipine 30 mg/day, with the possible up-titration to amlodipine 10 mg/day or nifedipine-GITS 60 mg/day at 4 weeks of follow-up.

RESULTS

The proportion of up-titration to higher dosages of antihypertensive drugs at 4 weeks of follow-up was higher in patients who commenced treatment in autumn/winter ( n  = 302) than those who commenced treatment in spring/summer ( n  = 199, 24.5 vs. 12.0%, P  < 0.001). The control rate of clinic blood pressure, however, was lower in autumn/winter than in spring/summer at 4 (56.7 vs. 70.7%, P  = 0.003) and 8 weeks of follow-up (52.5 vs. 74.9%, P  < 0.001). At 8 weeks, patients who commenced treatment in autumn/winter, compared with those who commenced treatment in spring/summer, had a significantly ( P ≤0.03) smaller daytime (mean between-season difference -3.2/-2.8 mmHg) but greater nighttime SBP/DBP reduction (3.6/1.6 mmHg). Accordingly, at 8 weeks, the prevalence of nondippers was significantly ( P  < 0.001) higher in spring/summer than in autumn/winter for both SBP (54.8 vs. 30.0%) and DBP (53.4 vs. 28.8%).

CONCLUSION

Clinic blood pressure-guided antihypertensive treatment requires a higher dosage of medication in cold than warm seasons, which may have led to over- and under-treatment of nighttime blood pressure, respectively.

Seasonal effects on blood pressure variability in treated hypertensive patients assessed by office, home, and ambulatory measurements

This study investigated the seasonal effect on blood pressure (BP) variability. Patients on stable antihypertensive drug treatment were assessed with office (OBP), home (HBP), and ambulatory BP (ABP) measurements in winter, next summer, and in next winter. Fifty-eight participants with full data for winter and summer were analyzed (mean age 65.2 ± 7.9 [SD], 64% males). OBP, HBP and ABP (24-h; daytime) were lower in summer than in winter (P < 0.01), whereas nighttime ABP was unchanged (p = NS). Standard deviation (SD), coefficient of variation (CV) and average real variability (ARV) for systolic OBP were higher in winter than summer (p < 0.01/ < 0.05/ < 0.01, respectively). These indices for HBP and ABP measurements did not differ in winter and summer (p = NS). Forty participants had complete data for winter-summer-next winter and HBP/ABP variability indices did not differ for both winters versus summer. These preliminary data suggest that BP variability is unaffected by seasonal changes in contrast to average BP levels.

Seasonal variations of the prevalence of metabolic syndrome and its markers using big-data of health check-ups

BACKGROUND

It is crucial to understand the seasonal variation of Metabolic Syndrome (MetS) for the detection and management of MetS. Previous studies have demonstrated the seasonal variations in MetS prevalence and its markers, but their methods are not robust. To clarify the concrete seasonal variations in the MetS prevalence and its markers, we utilized a powerful method called Seasonal Trend Decomposition Procedure based on LOESS (STL) and a big dataset of health checkups.

METHODS

A total of 1,819,214 records of health checkups (759,839 records for men and 1,059,375 records for women) between April 2012 and December 2017 were included in this study. We examined the seasonal variations in the MetS prevalence and its markers using 5 years and 9 months health checkup data and STL analysis. MetS markers consisted of waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), fasting plasma glucose (FPG).

RESULTS

We found that the MetS prevalence was high in winter and somewhat high in August. Among men, MetS prevalence was 2.64 ± 0.42 (mean ± SD) % higher in the highest month (January) than in the lowest month (June). Among women, MetS prevalence was 0.53 ± 0.24% higher in the highest month (January) than in the lowest month (June). Additionally, SBP, DBP, and HDL-C exhibited simple variations, being higher in winter and lower in summer, while WC, TG, and FPG displayed more complex variations.

CONCLUSIONS

This finding, complex seasonal variations of MetS prevalence, WC, TG, and FPG, could not be derived from previous studies using just the mean values in spring, summer, autumn and winter or the cosinor analysis. More attention should be paid to factors affecting seasonal variations of central obesity, dyslipidemia and insulin resistance.

Meta-Analysis of Pulse Transition Features in Non-Invasive Blood Pressure Estimation Systems: Bridging Physiology and Engineering Perspectives

The pulse transition features (PTFs), including pulse arrival time (PAT) and pulse transition time (PTT), hold significant importance in estimating non-invasive blood pressure (NIBP). However, the literature showcases considerable variations in terms of PTFs' correlation with blood pressure (BP), accuracy in NIBP estimation, and the comprehension of the relationship between PTFs and BP. This inconsistency is exemplified by the wide-ranging correlations reported across studies investigating the same feature. Furthermore, investigations comparing PAT and PTT have yielded conflicting outcomes. Additionally, PTFs have been derived from various bio-signals, capturing distinct characteristic points like the pulse's foot and peak. To address these inconsistencies, this study meticulously reviews a selection of such research endeavors while aligning them with the biological intricacies of blood pressure and the human cardiovascular system (CVS). Each study underwent evaluation, considering the specific signal acquisition locale and the corresponding recording procedure. Moreover, a comprehensive meta-analysis was conducted, yielding multiple conclusions that could significantly enhance the design and accuracy of NIBP systems. Grounded in these dual aspects, the study systematically examines PTFs in correlation with the specific study conditions and the underlying factors influencing the CVS. This approach serves as a valuable resource for researchers aiming to optimize the design of BP recording experiments, bio-signal acquisition systems, and the fine-tuning of feature engineering methodologies, ultimately advancing PTF-based NIBP estimation.

The Modern Environment: The New Secondary Cause of Hypertension?

The most important risk factor for cardiovascular disease, the leading cause of death worldwide, is hypertension. Although most cases of hypertension are thought to be essential, the multifactorial associations of the environmental influence on blood pressure seem to play an important role and should be more closely investigated. This review attempts to focus on the recent literature that examines the environmental effects on arterial blood pressure and its management. Seasonal variability and the role of ambient temperature, either occupational or recreational noise pollution, as well as obesity due to environment-caused dietary habits, are recognized as important risk factors, affecting the onset as well as the regulation of hypertension. Furthermore, the effects of seasonal fluctuations in blood pressure, noise pollution, and obesity seem to share a similar pathogenesis, and as such to all further react together, leading to increased blood pressure. The activation of the autonomous nervous system plays a key role and causes an increase in stress hormones that generates oxidative stress on the vascular system and, thus, vasoconstriction. In this review, by focusing on the association of the environmental impact with arterial blood pressure, we come to the question of whether most cases of hypertension-if not all-should, indeed, be considered primary or secondary.

Influence of temperature on the risk of gestational diabetes mellitus and hypertension in different pregnancy trimesters

Previous studies have proved that exposure to extreme temperature in specific windows of pregnancy could cause some complications, such as pregnancy induced hypertension (PIH) and gestational diabetes mellitus (GDM), but differences in the effect of extreme temperature on the 2 complications are rarely studied. We carried a retrospective study on the impact of temperature on GDM/PIH in different trimesters based on data from a maternal and child health center in Beijing, China. Ambient temperatures (°C) were obtained from the China Meteorological Administration from January 1st, 2013 to May 15th, 2018. We use distributed lag non-linear models (DLNMs) combined with logistic regression to calculate the lag exposure-response relationships between the temperature and GDM/PIH from 1st to 24th/20th weeks of pregnancy. In both first and second trimesters, the risk of GDM was increased in summer with high temperatures; in second trimester, the risk of GDM increased in winter with low temperatures. In first half of pregnancy, risk of PIH was decreased in winter with low temperatures. These findings can provide the guideline for preventing the GDM and PIH induced by extreme temperature during pregnancy.

Gender-specific effect of outdoor temperature and seasonal variation on blood pressure components: a cross-sectional study on Iranian adults from 2015 to 2018

Blood pressure (BP) is influenced by both individual and environmental factors such as ambient temperature. However, the gender-stratified and component-specific impact of temperature on BP is not well understood. Herein, we examined the temperature and seasonal effects on four main BP components, namely systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), and pulse pressure (PP), in both genders. A total of 8990 (3954 men) Tehranian adults during 2015-2018 were included. Linear regression models for analyzing data in three models including unadjusted, age-adjusted, and further adjusted for known sociodemographic and cardiovascular confounders were conducted. Among women, each 10 °C increment was associated with a significant decrease of - 0.48 mmHg (95% confidence interval (CI): - 0.86, - 0.19) and - 0.65 mmHg (- 0.76, - 0.41) in SBP and MAP, respectively. In men, the corresponding value for SBP was - 0.46 (- 0.82, - 0.16) mmHg (P = 0.058). Gender-specific analysis in each season showed that among women, PP increased in autumn and winter with each 10 °C decrease (P < 0.05). The mean increase in SBP (3.4 and 2.06 mmHg in women and men, respectively), DBP (1.66 and 1.19 mmHg), and MAP (2.71 and 1.12 mmHg) was observed during winter compared to summer (all P < 0.05). PP showed seasonality only in women (1.46 mmHg, P-value = 0.003). In both genders, SBP in age > 60 years was more susceptible to variation compared to younger ages. Furthermore, obese women had more SBP changes compared to their non-obese counterparts (all P for interaction < 0.05). In conclusion, there was a sex difference in BP response to the outdoor temperature, with higher vulnerability among women. The reverse relation between temperature and BP occurred particularly among elderly and obese individuals. Careful monitoring of BP in cold seasons, specifically in the mentioned subgroups, could potentially attenuate cardiovascular risks.

Blood pressure variability: methodological aspects, clinical relevance and practical indications for management - a European Society of Hypertension position paper ∗

Blood pressure is not a static parameter, but rather undergoes continuous fluctuations over time, as a result of the interaction between environmental and behavioural factors on one side and intrinsic cardiovascular regulatory mechanisms on the other side. Increased blood pressure variability (BPV) may indicate an impaired cardiovascular regulation and may represent a cardiovascular risk factor itself, having been associated with increased all-cause and cardiovascular mortality, stroke, coronary artery disease, heart failure, end-stage renal disease, and dementia incidence. Nonetheless, BPV was considered only a research issue in previous hypertension management guidelines, because the available evidence on its clinical relevance presents several gaps and is based on heterogeneous studies with limited standardization of methods for BPV assessment. The aim of this position paper, with contributions from members of the European Society of Hypertension Working Group on Blood Pressure Monitoring and Cardiovascular Variability and from a number of international experts, is to summarize the available evidence in the field of BPV assessment methodology and clinical applications and to provide practical indications on how to measure and interpret BPV in research and clinical settings based on currently available data. Pending issues and clinical and methodological recommendations supported by available evidence are also reported. The information provided by this paper should contribute to a better standardization of future studies on BPV, but should also provide clinicians with some indications on how BPV can be managed based on currently available data.

The accuracy of 8-hour ambulatory blood pressure monitoring, adjusted to seasons

Ambulatory blood pressure monitoring (ABPM) is considered the most reliable and accurate measurement of blood pressure (BP). However, the use of ABPM has some limitations, which make it difficult to complete for the entire 24 h. We aimed to establish in which part of the day BP measurements are in highest correlation with full ABPM (over 24 h) results. We performed a retrospective cross-sectional study which included 3113 full ABPM. Each ABPM was divided into 6- and 8-hour segments, and mean BP in each time segment was calculated. Linear mix models for describing BP by BP in each time segment were performed. A total of 3113 ABPM measurements carried out on 2676 patients (mean age 57.78 ± 14.74) were included in the study. Linear mix models demonstrated significant association between mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) in full ABPM, and SBP and DBP between 2-10 PM, respectively (SBP: β = 0.902, p < 0.001; DBP: β = 0.839, p < 0.001), adjusted for gender, age, season, and relevant interactions. This section had higher coefficient correlations than other sections which were examined. The study findings indicate high correlation between BP between 2-10 PM, and BP in full-ABPM, by each season. This time segment may be ideal for short-term BP monitoring as an initial screening test and for patients who are unable to complete full ABPM. However, since this time segment does not include nighttime hours, there is a risk of underdiagnosis of non-dipper.

Seasonal variation in the effect of antihypertensive treatment with the irbesartan/hydrochlorothiazide combination

There is increasing awareness of seasonal variation in blood pressure (BP). In the present analysis, we investigated seasonal variation in the antihypertensive treatment effect of the irbesartan/hydrochlorothiazide combination in patients with stage 2 and 3 hypertension. The study participants were hypertensive patients enrolled in a 12-week therapeutic study. Antihypertensive treatment was initiated with irbesartan/hydrochlorothiazide 150/12.5 mg/day, with possible uptitration to 300/12.5 mg/day and 300/25 mg/day at 4 and 8 weeks of follow-up, respectively. The month of treatment commencement was classified as spring/summer (May to August) and autumn/winter (September to December). Of the 501 enrolled patients, 313 and 188 commenced antihypertensive treatment in spring/summer and autumn/winter, respectively. The mean changes in systolic/diastolic BP at 8 and 12 weeks of follow-up were greater in patients who commenced treatment in autumn/winter (-32.3/-16.5 and -34.2/-16.7 mmHg, respectively) than those who commenced treatment in spring/summer (-28.4/-13.9 and -27.1/-12.8 mmHg, respectively), with a between-season difference of 3.9 (95% confidence interval [CI], 1.4-6.4, P = 0.002)/2.6 (95% CI, 0.9-4.2, P = 0.002) mmHg and 7.0 (95% CI, 4.7-9.3, P < 0.0001)/3.9 (95% CI, 2.4-5.4, P < 0.0001) mmHg, respectively. Further subgroup analyses according to several baseline characteristics showed a greater between-season difference in the changes in systolic BP in patients aged ≥55 years than in those <55 years (n = 255, 12.6 mmHg vs. n = 246, 6.9 mmHg, P = 0.02), especially in patients who did not use antihypertensive medication at baseline (n = 94, 15.4 mmHg vs. n = 132, 5.4 mmHg, P = 0.006). In conclusion, there is indeed seasonality in the antihypertensive treatment effect, with a greater BP reduction in patients who commenced treatment in cold than warm seasons.

Seasonal variation of ambulatory blood pressure in Chinese hypertensive adolescents

BACKGROUND

Blood pressure (BP) exhibits seasonal variation with lower levels at higher temperatures and vice versa. This phenomenon affects both sexes and all age groups. So far, only a few research studies have investigated this condition in adolescents and none of them were based on hypertensive population or ever applied ambulatory blood pressure monitor (ABPM). Therefore, we carried out the first study that used ABPM to record seasonal variation of blood pressure in hypertensive adolescents.

METHODS

From March 2018 to February 2019, 649 ABPMs from hypertensive adolescents between 13 and 17 years who were referred to wear an ABPM device in Beijing and Baoding were extracted. Seasonal change in ambulatory BP value, dipping status, and prevalence of different BP phenotypes were analyzed and compared.

RESULTS

Mean age of participants was 14.9 ± 1.5 years and 65.8% of them were boys. Of the participants, 75.3% met the criteria of overweight or obesity. From summer to winter, average 24-hour, day-time, and night-time BP showed significant rise, which was 9.8/2.8, 9.8/3.0, and 10.9/3.4 mmHg, respectively. This seasonal effect on BP was not dependent on the obesity degree. In addition, higher prevalence of nondippers and risers existed in winter while white coat hypertension was more frequent in warmer seasons.

CONCLUSION

Hypertensive adolescents showed evident seasonal change in their ABPM results, which was featured by elevated BP level and more frequent abnormal dipping patterns in winter. On the contrary, higher prevalence of white coat hypertension was found in warmer seasons. Physicians should take seasonal variation into consideration when managing adolescent hypertension.

Novel insights into the association between seasonal variations, blood pressure, and blood pressure variability in patients with new-onset essential hypertension

Background

Blood pressure (BP) exhibits seasonal variations, with peaks reported in winter. However, the association between seasonal variations and blood pressure variability in patients with new-onset essential hypertension is not fully understood. This study evaluated the potential association of seasonal variations with new-onset essential hypertension.

Methods

This retrospective observational study recruited a total of 440 consecutive patients with new-onset essential hypertension who underwent 24-h ambulatory electrocardiograph (ECG) and BP measurement at our department between January 2019 and December 2019. Demographic and baseline clinical data including BP variability, heart rate variability, and blood tests were retrieved. Multivariate linear regression analysis was performed to identify factors independently associated with mean BP and BP variability.

Results

Among the 440 patients recruited, 93 cases were admitted in spring, 72 in summer, 151 in autumn, and 124 in winter. Univariate analysis revealed that systolic BP (SBP), diastolic BP (DBP), high-sensitivity C-reactive protein, SBP drop rate, DBP drop rate, 24-h standard deviation of SBP, 24-h standard deviation of DBP, 24-h SBP coefficient of variation, and 24-h DBP coefficient of variation were associated with patients admitted in winter (P < 0.05 for all). Multivariate linear regression analysis showed that winter was the influencing factor of 24-h standard deviation of SBP (B = 1.851, t = 3.719, P < 0.001), 24-h standard deviation of DBP (B = 1.176, t = 2.917, P = 0.004), 24-h SBP coefficient of variation (B = 0.015, t = 3.670, P < 0.001), and 24-h DBP coefficient of variation (B = 0.016, t = 2.849, P = 0.005) in hypertensive patients.

Conclusions

Seasonal variations are closely associated with BP variability in patients with new-onset essential hypertension. Our study provides insight into the underlying pathogenesis of new-onset essential hypertension.

Impact of weather changes on hospital admissions for hypertension

Blood pressure (BP) shows a seasonal variation with higher levels at lower temperatures. Many hypertensives, however, report on BP disturbances rather in association with acutely changing weather conditions than with absolute temperatures. To date, the impact of changing meteorological parameters on hypertensive episodes remains elusive. We performed a retrospective time series regression analysis on 203,703 patients in three hospitals in Germany between 2010 and 2018, of whom 7362 patients were admitted for hypertensive disease. Numbers of daily admissions for hypertension were associated with metereological data obtained from three nearby weather stations. Data comprised temperature (mean, maximal, minimal and range within 24 h), athmospheric pressure, and precipitation. Changes of these parameters were calculated over a two and three day period. There was an inverse correlation between maximal daily temperature and the number of admissions for hypertensive disease, which remained significant both after adjustment for seasonality and week day in a spline model and in a constrained distributed lag model. A decrease of maximal temperature by 5 °C was associated with a 3% increase of risk for admission for hypertension and vice versa. There were no significant effects of precipitation and athmospheric pressure on the number of admissions. With regard to all observed metereological parameters, neither the change within two, nor within three days was consistently associated with the number of daily admissions. High temperatures are associated with lower numbers of hypertensive episodes requiring hospital admission. In contrast to the subjective perception of many hypertensive patients, however, acutely changing weather conditions are not associated with a higher risk of hypertensive emergency.

Seasonal variation of ambulatory blood pressure in Chinese hypertensive adolescents

BACKGROUND

Blood pressure (BP) exhibits seasonal variation with lower levels at higher temperatures and vice versa. This phenomenon affects both sexes and all age groups. So far, only a few research studies have investigated this condition in adolescents and none of them were based on hypertensive population or ever applied ambulatory blood pressure monitor (ABPM). Therefore, we carried out the first study that used ABPM to record seasonal variation of blood pressure in hypertensive adolescents.

METHODS

From March 2018 to February 2019, 649 ABPMs from hypertensive adolescents between 13 and 17 years who were referred to wear an ABPM device in Beijing and Baoding were extracted. Seasonal change in ambulatory BP value, dipping status, and prevalence of different BP phenotypes were analyzed and compared.

RESULTS

Mean age of participants was 14.9 ± 1.5 years and 65.8% of them were boys. Of the participants, 75.3% met the criteria of overweight or obesity. From summer to winter, average 24-hour, day-time, and night-time BP showed significant rise, which was 9.8/2.8, 9.8/3.0, and 10.9/3.4 mmHg, respectively. This seasonal effect on BP was not dependent on the obesity degree. In addition, higher prevalence of nondippers and risers existed in winter while white coat hypertension was more frequent in warmer seasons.

CONCLUSION

Hypertensive adolescents showed evident seasonal change in their ABPM results, which was featured by elevated BP level and more frequent abnormal dipping patterns in winter. On the contrary, higher prevalence of white coat hypertension was found in warmer seasons. Physicians should take seasonal variation into consideration when managing adolescent hypertension.

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.

Effects of seasonal and climate variations on in-hospital mortality and length of stay in patients with type A aortic dissection

Objective

To investigate the effects of seasonal and climatic changes on postoperative in-hospital mortality and length of stay (LOS) in patients with type A acute aortic dissection (AAD).

Methods

Patients undergoing implantation of the modified triple-branched stent graft to replace the descending aorta in addition to aortic root reconstruction for type A AAD in our hospital from January 2016 to December 2019 were included. Relevant data were retrospectively collected and analyzed.

Results

A total of 404 patients were included in our analyses. The multivariate unconditional logistic regression analysis showed that patients admitted in autumn (OR 4.027, 95% CI 1.023–17.301, P = 0.039) or with coronary heart disease (OR 8.938, 95% CI 1.991–29.560, P = 0.049) were independently associated with an increased risk of postoperative in-hospital mortality. Furthermore, patients admitted in autumn (OR 5.956, 95% CI 2.719–7.921, P = 0.041) or with hypertension (OR 3.486, 95% CI 1.192–5.106, P = 0.035) were independently associated with an increased risk of longer LOS.

Conclusion

Patients admitted in autumn or with coronary heart disease are at higher risk of in-hospital mortality following surgery for type A AAD. Also, patients admitted in autumn or with hypertension have a longer hospital LOS. In the autumn of the temperature transition, we may need to strengthen the management of medical quality after surgery for type A AAD.

Relationship Between Home Blood Pressure and the Onset Season of Cardiovascular Events: The J-HOP Study (Japan Morning Surge-Home Blood Pressure)

BACKGROUND

The incidence of cardiovascular disease (CVD) increases during winter. The risk that elevated home blood pressure (BP) poses for CVD events that occur in each of 4 seasons is unclear. We conducted a post hoc analysis using the dataset from a nationwide cohort, the Japan Morning Surge-Home Blood Pressure (J-HOP) study, to assess the association between home BP and winter-onset CVD events.

METHODS

J-HOP participants who had cardiovascular risks conducted morning and evening home BP measurements for a 14-day period and were followed-up for the occurrence of CVD events.

RESULTS

We analyzed 4,258 participants (mean age 64.9 years; 47% male; 92% hypertensives) who were followed-up for an average of 6.2 ± 3.8 years (26,295 person-years). We divided the total of 269 CVD events (10.2/1,000 person-years) by the season of onset as follows: 82 in the winter and 187 in the other seasons (spring, summer, and autumn). In the Cox models adjusted for covariates and the season when home BPs were measured at baseline, morning home systolic BP (SBP) was associated with both winter-onset and other season-onset CVD events: hazard ratio (HR) for winter 1.22, 95% confidence interval (CI) 1.06-1.42 per 10 mm Hg; HR for other seasons 1.11, 95% CI 1.00-1.23. Evening home SBP was associated with the other season-onset CVD events (HR 1.20, 95% CI 1.08-1.33 per 10 mm Hg), but not with the winter-onset CVD events.

CONCLUSIONS

Our findings indicate that compared with evening home BP, morning home BP might be a superior predictor of winter-onset CVD events.

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.

Association between Physical Activity and Seasonal Variations in Metabolic and Vascular Function in Adults

This article highlights the association between physical activity (PA) and seasonal variations in metabolic and vascular function in adults. Increasing PA is an important method for preventing cardiovascular disease (CVD) and all-cause mortality by improving blood glucose, blood pressure, blood lipid profiles, body fat, insulin resistance, and vascular function, such as endothelial function. Conversely, various factors, such as seasonal climate conditions, may affect the amount of PA that individuals undertake. Changes in PA often induce seasonal variations in metabolic and vascular function; the deterioration of such functions in winter is the most prominent, and there is clear evidence of an increased risk of CVD in this season. Understanding the influence of PA on seasonal variations observed in metabolic and vascular function is necessary for the management of these physiological functions. In this article summary, few studies have proven that maintaining PA can suppress the variations, and it remains unclear what types, intensities, and durations of regular PA are effective for circumventing seasonal impact. In addition to further studies, there is a need to educate individuals about the strategies to manage PA and other aspects of their lifestyles throughout the year, particularly in winter.

Efficacy of individualized homeopathic medicines in intervening the progression of pre-hypertension to hypertension: A double-blind, randomized, placebo-controlled trial

CONTEXT

Pre-hypertension remains a significant public health challenge and appropriate intervention is required to stop its progression to hypertension and/or cardiovascular diseases.

OBJECTIVE

To study the effects of individualized homeopathic medicines (IH) against placebo in intervening with the progression of pre-hypertension to hypertension.

DESIGN

Double-blind, randomized, two parallel arms, placebo-controlled trial.

SETTING

Outpatient departments of D. N. De Homoeopathic Medical College and Hospital, Kolkata, West Bengal, India.

PATIENTS

Ninety-two patients suffering from pre-hypertension; randomized to receive either IH (n = 46) or identical-looking placebo (n = 46).

INTERVENTIONS

IH or placebo in the mutual context of lifestyle modification (LSM) advices including dietary approaches to stop hypertension (DASH) and brisk exercises.

MAIN OUTCOME MEASURES

Primary - systolic and diastolic blood pressure (SBP and DBP); secondary - Measure Yourself Medical Outcome Profile version 2.0 (MYMOP-2) scores; all measured at baseline, and every month, up to 3 months.

RESULTS

After 3 months of intervention, the number of patients having progression from pre-hypertension to hypertension between groups were similar without any significant differences in between (all P>0.05). Reduction in BP and MYMOP-2 scores were non-significantly higher (all P>0.05) in the IH group than placebo with small effect sizes. Lycopodium clavatum, Thuja occidentalis and Natrum muriaticum were the most frequently prescribed medicines. No harms or serious adverse events were reported from either group. Thus, there was a small, but non-significant direction of effect favoring homeopathy, which ultimately rendered the trial as inconclusive. [Trial registration: CTRI/2018/10/016,026; UTN: U1111-1221-8251].

[Improved office blood pressure control by automatic delayed-reading oscillometric device]

INTRODUCTION

Office blood pressure (BP) measurement is a recommended procedure, although the out-of-office BP measurements are increasingly used.

OBJECTIVE

To know the degree of BP control by clinical measurement.

MATERIAL AND METHODS

During November 2019 demographic and clinical data, office attended systolic BP (SBP) and diastolic BP (DBP) measured with an automatic device with delayed reading and, if performed, data from ambulatory BP monitoring (ABPM) were collected.

RESULTS

102 patients (67 men) were included, with a mean age of 64.9 years, 30% diabetic and 34% with cardiovascular complications. 70% had a controlled hypertesion (<140/90 mmHg) by office BP, the mean SBP was 131 ± 16.5 mmHg and the DBP was 73 ± 9.5 mmHg. Old age and diabetes were associated with uncontrolled hypertension. Thirty three patients had ABPM data, which allowed them to be classified according to the 24-hour BP into: 30% true normotension, 9% white-coat hypertension, 15% sustained hypertension, and 45% masked hypertension.

CONCLUSION

The use of automatic devices reduces the white-coat phenomenon, improving the % of patients with office BP controlled. However, this is not confirmed outside the clinic, showing the importance of ABPM in the evaluation of hypertension control. Office BP measurement is useful in patients initial assessment and also provides educational aspects, although the methodology must be optimized to define its clinical role.

Effects of weather and season on human brain volume

We present an exploratory cross-sectional analysis of the effect of season and weather on Freesurfer-derived brain volumes from a sample of 3,279 healthy individuals collected on two MRI scanners in Hartford, CT, USA over a 15 year period. Weather and seasonal effects were analyzed using a single linear regression model with age, sex, motion, scan sequence, time-of-day, month of the year, and the deviation from average barometric pressure, air temperature, and humidity, as covariates. FDR correction for multiple comparisons was applied to groups of non-overlapping ROIs. Significant negative relationships were found between the left- and right- cerebellum cortex and pressure (t = -2.25, p = 0.049; t = -2.771, p = 0.017). Significant positive relationships were found between left- and right- cerebellum cortex and white matter between the comparisons of January/June and January/September. Significant negative relationships were found between several subcortical ROIs for the summer months compared to January. An opposing effect was observed between the supra- and infra-tentorium, with opposite effect directions in winter and summer. Cohen’s d effect sizes from monthly comparisons were similar to those reported in recent psychiatric big-data publications, raising the possibility that seasonal changes and weather may be confounds in large cohort studies. Additionally, changes in brain volume due to natural environmental variation have not been reported before and may have implications for weather-related and seasonal ailments.

School-based surveillance on visit-to-visit blood pressure variability and high blood pressure in children and adolescents

BACKGROUND

The predictive importance of visit-to-visit blood pressure variability (VVV) for high blood pressure (HBP) in a pediatric population has been largely unsettled. We aimed to evaluate it based on Health Promotion Program for Children and Adolescents (HPPCA), a school-based surveillance conducted from 2012 to 2018 in Suzhou, China.

METHODS

A total of 330,618 participants had BP measurement in 2018 and ≥ 3 BP records during 2012-2017, were recruited from HPPCA. Absolute BP values (in mmHg) were converted into age-, sex- and height- normalized z-scores. VVV was expressed as standard deviation (SD), coefficient of variation (CV) or average real variability (ARV) of BP z-scores during 2012-2017. Logistic regression models were used to assess the associations between VVV and HBP in 2018.

RESULTS

In 2018, 42,554 (12.87%) subjects were defined as HBP. VVV, except for SBP-CV and DBP-CV, was significantly higher in the HBP group than normotensives group. After adjusting for covariates including mean BP values from 2012 to 2017, SBP-SD, SBP-ARV, DBP-SD and DBP-ARV, increased the risk of HBP by 5.70 [95% confidence interval (95% CI) 5.54-5.87], 4.10 (95% CI 4.01-4.20), 4.70 (95% CI 4.50-4.90) and 3.39 (95% CI 3.28-3.50) times, respectively. Notably, SBP-SD significantly improved risk discrimination of HBP based on other risk variables (c-statistics, net reclassification index and integrated discrimination improvement significantly increased).

CONCLUSIONS

Higher SD or ARV of BP, was independently related with higher probability of HBP in Chinese pediatric population. SBP-SD could be potentially helpful for detecting HBP. Future researches investigating the predictive value of VVV are warrant.

Effect of maintaining supervised gym- and home-based exercises on the seasonal variations of metabolic outcomes in overweight and obese Japanese adults

Objectives

This study aimed to examine whether maintaining supervised gym- and home-based exercises for an extended time of period could decrease seasonal variations of metabolic outcomes in overweight and obese Japanese adults.

Methods

This retrospective study recruited 54 overweight and obese outpatients who started exercising in 2006–2010 and analysed their metabolic outcomes for 5 years from March 2011 to February 2016. In this group, 26 participants performed moderate-intensity aerobic exercise (MIAE) for 30–40 min/day for at least 2 days/week, supervised by physical therapists at a hospital gym (GYM) during the observation period. Conversely, 28 participants were asked to perform MIAE by themselves at or around their homes (HOME) for the same duration.

Results

The body mass index (BMI), waist circumference and homoeostasis model assessment of insulin resistance (HOMA-IR) values in winter were higher than those in other seasons in the HOME group but not in the GYM group. The annual ranges of BMI, waist circumference, fasting plasma glucose and HOMA-IR in the GYM group were smaller than those in the HOME group.

Conclusion

Maintaining supervised gym-based exercise, as opposed to home-based exercise, may decrease seasonal variations of some metabolic outcomes in overweight and obese Japanese adults.

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.

Questionnaire survey assessing seasonal changes in lower urinary tract symptoms in men with benign prostate hyperplasia

OBJECTIVE

A prospective questionnaire survey was conducted for patients with benign prostatic hyperplasia (BPH) to clarify seasonal changes in the lower urinary tract symptoms (LUTS).

MATERIAL AND METHODS

Male patients receiving α1-adrenoreceptor antagonists for BPH were enrolled. They answered the International Prostate Symptom Score (IPSS) questionnaire, and an unvalidated questionnaire that consisted of 10 questions assessing variations in the urinary stream (voiding symptoms) and urinary frequency (storage symptoms), depending upon the seasons or the patients' subjective sensations of warm and cold in last one year.

RESULTS

A total of 412 participants answered IPSS and our unvalidated questionnaire. Of the 412 participants, 36.7% and 59.0% realized seasonal variations in urinary stream and frequency, respectively. Among patients perceiving seasonal urinary stream and urinary frequency changes (n=151 and n=243, respectively), significantly more patients realized weaker urinary stream, 59.8% (107/179) in winter compared with 26.2% (47/179) in summer, and increased urinary frequency, 69.8% (199/285) in winter compared with 20.7% (59/285) in summer (p<0.0001 and p<0.0001, respectively). Even in summer, when feeling cold, 34.7% and 56.3% realized a weaker urinary stream and an increased urinary frequency, and even in winter, when feeling warm, 53.4% and 69.4% realized a stronger urinary stream and a decreased urinary frequency. Those with seasonal stream changes showed a significantly higher IPSS total, voiding and post-voiding scores than those without, and those with seasonal frequency changes showed significantly higher IPSS total, storage, voiding, and post-voiding scores.

CONCLUSION

Our results revealed seasonal changes and feeling of hot and cold were associated with subjective changes of LUTS in BPH patients.

Seasonal Variation of Home Blood Pressure and Its Association With Target Organ Damage: The J-HOP Study (Japan Morning Surge-Home Blood Pressure)

Background

Although seasonal variation of home blood pressure (BP) has been reported to be higher in winter, seasonal difference in home BP (HBP) and its association with target organ damage (TOD) remains unclear.

Methods

This is a cross-sectional study using the dataset from the Japan Morning Surge-Home Blood Pressure (J-HOP) study to assess seasonal differences in HBP, prevalence of masked hypertension, and association of HBP with TOD. The J-HOP study is a nationwide, multicenter prospective study whose participants with cardiovascular risks underwent morning and evening HBP measurements for a 14-day period in 71 institutions throughout Japan. Urine albumin–creatinine ratio (UACR) and serum-B-type natriuretic peptide (BNP) were obtained at enrollment.

Results

Among 4,267 participants (mean age, 64.9 ± 10.9 years; 46.9% male; 91.4% hypertensives), 1,060, 979, 1,224, and 1,004 participants were enrolled in spring, summer, autumn, and winter, respectively. Morning and evening home systolic/diastolic BP levels, and prevalence of masked hypertension (office BP <140/90 mm Hg and HBP ≥135/85 mm Hg) were significantly lower in summer than other seasons after adjustment for covariates. When we assessed the interaction between BP parameters and each season for an association with TOD, we found the association between morning home diastolic BP and each of UACR and BNP was stronger in winter than other seasons (both P for interaction <0.05).

Conclusions

In this study, we revealed that the prevalence of masked hypertension was higher in other seasons than in summer and found a notable association between morning home diastolic BP and TOD in winter.

Nocturnal blood pressure measured by home devices: evidence and perspective for clinical application

: Studies using ambulatory blood pressure (BP) monitoring have shown that BP during night-time sleep is a stronger predictor of cardiovascular outcomes than daytime ambulatory or conventional office BP. However, night-time ambulatory BP recordings may interfere with sleep quality because of the device cuff inflation and frequency of measurements. Hence, there is an unmet need for obtaining high quality BP values during sleep. In the last two decades, technological development of home BP devices enabled automated BP measurements during night-time. Preliminary data suggest that nocturnal home BP measurements yield similar BP values and show good agreement in detecting nondippers when compared with ambulatory BP monitoring. Thus, nocturnal home BP measurements might be a reliable and practical alternative to ambulatory BP monitoring to evaluate BP during sleep. As the use of home BP devices is widespread, well accepted by users and has relatively low cost, it may prove to be more feasible and widely available for routine clinical assessment of nocturnal BP. At present, however, data on the prognostic relevance of nocturnal BP measured by home devices, the optimal measurement schedule, and other methodological issues are lacking and await further investigation. This article offers a systematic review of the current evidence on nocturnal home BP, highlights the remaining research questions, and provides preliminary recommendations for application of this novel approach in BP management.

Seasonal variation in home blood pressure and its relationship with room temperature in patients with type 2 diabetes

Our aim was to examine the seasonal variations in home blood pressure measurements and the relationship of ambient temperature or room temperature with the seasonal variations in home blood pressure measurements using a home blood pressure telemonitoring system in patients with type 2 diabetes. The home blood pressure measurements of 41 patients with type 2 diabetes were self-measured. Patients performed triplicate morning and evening blood pressure measurements at least 5 days per month for 12 consecutive months. The lowest values of both systolic blood pressure and diastolic blood pressure were observed in August (126.3 and 70.4 mmHg, respectively), and the highest systolic and diastolic blood pressure values were observed in January (140.3 and 76.9 mmHg, respectively). The root mean squared error between the mean systolic blood pressure and room temperature was 6.50 mmHg and between mean systolic blood pressure and ambient temperature was 6.55 mmHg. Using a home blood pressure telemonitoring system, this study revealed for the first time that home blood pressure varied seasonally, with the highest values observed in January and the lowest values observed in August, and that the seasonal variations in home blood pressure were related to room temperature as well as ambient temperature.

Seasonal variation of novel arterial stiffness indexes in Japanese hypertensive patients

Background and Objective: Seasonal variation of blood pressure (BP) is well known, and a relationship between increases in BP and the incidence of cardiovascular accidents (CVAs) in the winter has been reported. Parameters of arterial stiffness may exhibit seasonal variation; however, available data are currently limited. Novel arterial stiffness indexes, namely the arterial velocity pulse index (AVI) and arterial pressure-volume index (API), can be determined through usual maneuver for BP measurement during the regular examination in the outpatient clinic.The present study assessed the seasonal variation of AVI and API in 59 hypertensive patients undergoing stable treatment and regularly visiting our outpatient clinic over a period of 30 months. Methods: BP, pulse rate (PR), AVI, and API were measured using the AVE-1500 (Pasesa) in the sitting position. Six time frames of assessment were established. All measurements (average: 17.9 measurements per person) were sorted using these six time frames, and their averages were used for analysis. Results: Significant seasonal variations in PR (P < 0.001) and AVI (P < 0.001), along with weak variation in systolic BP (SBP) (P = 0.047) and marginal variation in API (P = 0.055), were confirmed by repeated analysis of variance. SBP, API, and PR were decreased, whereas AVI was increased in the summer. Coefficient variations were SBP 5.1%, PR 4.9%, AVI 12.6%, and API 10.6%. Conclusion: AVI was associated with reflected wave like as augmentation index. Thus, a high AVI may suggest increased central wave reflection. Although the significance of seasonal variation of AVI remains unknown, AVI may influence seasonal variations in the incidence of CVA.

Association Between Amplitude of Seasonal Variation in Self-Measured Home Blood Pressure and Cardiovascular Outcomes: HOMED-BP (Hypertension Objective Treatment Based on Measurement By Electrical Devices of Blood Pressure) Study

Background

The clinical significance of long‐term seasonal variations in self‐measured home blood pressure (BP) has not been elucidated for the cardiovascular disease prevention.

Methods and Results

Eligible 2787 patients were classified into 4 groups according to the magnitude of their seasonal variation in home BP, defined as an average of all increases in home BP from summer (July–August) to winter (January–February) combined with all decreases from winter to summer throughout the follow‐up period, namely inverse‐ (systolic/diastolic, <0/<0 mm Hg), small‐ (0–4.8/0–2.4 mm Hg), middle‐ (4.8–9.1/2.4–4.5 mm Hg), or large‐ (≥9.1/≥4.5 mm Hg) variation groups. The overall cardiovascular risks illustrated U‐shaped relationships across the groups, and hazard ratios for all cardiovascular outcomes compared with the small‐variation group were 3.07 (P=0.004) and 2.02 (P=0.041) in the inverse‐variation group and large‐variation group, respectively, based on systolic BP, and results were confirmatory for major adverse cardiovascular events. Furthermore, when the summer‐winter home BP difference was evaluated among patients who experienced titration and tapering of antihypertensive drugs depending on the season, the difference was significantly smaller in the early (September–November) than in the late (December–February) titration group (3.9/1.2 mm Hg versus 7.3/3.1 mm Hg, P<0.001) as well as in the early (March–May) than in the late (June–August) tapering group (4.4/2.1 mm Hg versus 7.1/3.4 mm Hg, P<0.001).

Conclusions

The small‐to‐middle seasonal variation in home BP (0–9.1/0–4.5 mm Hg), which may be partially attributed to earlier adjustment of antihypertensive medication, were associated with better cardiovascular outcomes.

Relationship Between Blood Pressure Variability and Cognitive Function in Elderly Patients With Good Blood Pressure Control

BACKGROUND

Although higher blood pressure (BP) levels and BP variability have been associated with cognitive impairment, data are sparse regarding the relationship between BP variability and cognitive function in elderly patients with well BP control.

METHODS

We analyzed 232 ambulatory patients with one or more cardiovascular risk factors. All patients underwent ambulatory BP monitoring and the Japanese version of the Montreal Cognitive Assessment (MoCA-J).

RESULTS

The mean age was 77.7 ± 8.3 years; 33.6% were male, and 85.3% were taking antihypertensive drugs. The average 24-hour BP level was 118.7 ± 10.0/68.3 ± 6.4 mm Hg. When we divided the weighted SD of systolic BP (SBP) as a measure of BP variability into quartiles, the top quartile group (≥19.6 mm Hg) had a significantly lower total MoCA-J score (15.4 [95% confidence interval 14.2-16.7] vs. 17.9 [17.2-18.6], P = 0.001) and lower scores on several domains, visuoexecutive (2.2 [1.9-2.6] vs. 2.8 [2.6-2.9], P = 0.012), abstraction (1.0 [0.7-1.2] vs. 1.3 [1.1-1.4], P = 0.015), attention (2.8 [2.4-3.1] vs. 3.6 [3.4-3.8], P = 0.001), and naming (2.1 [1.9-2.3] vs. 2.5 [2.4-2.6], P = 0.001) than quartiles 1 through 3 combined, after adjustment for age and 24-hour SBP. These associations were not found in the quartiles of 24-hour SBP.

CONCLUSIONS

In elderly patients with well ambulatory BP control, higher BP variability but not average ambulatory BP level was associated with cognitive impairment.

Onset seasons and clinical outcomes in patients with Stanford type A acute aortic dissection: an observational retrospective study

OBJECTIVES

To evaluate the association of onset season with clinical outcome in type A acute aortic dissection (AAD).

DESIGN

A single-centre, observational retrospective study.

SETTING

The study was conducted in Fuwai Hospital, the National Centre for Cardiovascular Disease, Beijing, China.

PARTICIPANTS

From 2008 to 2010, a set of consecutive patients with type A AAD, confirmed by CT scanning, were enrolled and divided into four groups according to onset season: winter (December, January and February), spring (March, April and May), summer (June, July and August) and autumn (September, October and November). The primary end points were in-hospital death and all-cause mortality during follow-up.

RESULTS

Of the 492 cases in this study, 129 occurred in winter (26.2%), 147 in spring (29.9%), 92 in summer (18.7%), and 124 in autumn (25.2%). After a median follow-up of 20.4 months (IQR 9.7-38.9), the in-hospital mortality in cases occurring in autumn was higher than in the other three seasons (23.4% vs 8.4%, p<0.01). Long-term mortality was comparable among the four seasonal groups (p=0.63). After adjustment for age, gender and other risk factors, onset in autumn was still an independent factor associated with increased risk of in-hospital mortality (HR 2.05; 95% CI 1.15 to 3.64, p=0.02) in addition to surgical treatment. Further analysis showed that the seasonal effect on in-hospital mortality (autumn vs other seasons: 57.4% vs 27.3%, p<0.01) was only significant in patients who did not receive surgical treatment. No seasonal effect on long-term clinical outcomes was found in this cohort.

CONCLUSIONS

Onset in autumn may be a factor that increases the risk of in-hospital death from type A AAD, especially in patients who receive conservative treatment. Immediate surgery improves the short-term and long-term outcomes regardless of onset season.