Seasonal variations of blood pressure and overhydration in patients on chronic hemodialysis

Spósito, M.; Nieto, Fernando; Ventura, José E.

doi:10.1016/s0272-6386(00)70249-6

Cited by 37 publications

(31 citation statements)

References 19 publications

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“…Admittedly, unlike the study by Fine, neither in the present nor in the National Institutes of Health-sponsored Hemodialysis data was a distinction made between patients treated with or without antihypertensive agents. Ultrafiltration volume was lowest in summer and highest in winter, which is in agreement with other studies in which seasonal variations in BP and interdialytic weight gain were observed (3,23,24). However, in other studies, no relationship between variations in extracellular volume and seasonal variations in BP was observed.…”

Section: Discussionsupporting

confidence: 91%

Seasonal Variations in Mortality, Clinical, and Laboratory Parameters in Hemodialysis Patients

Usvyat

Carter

Thijssen

et al. 2012

Clinical Journal of the American Society of Nephrology

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SummaryBackground and objectives Mortality varies seasonally in the general population, but it is unknown whether this phenomenon is also present in hemodialysis patients with known higher background mortality and emphasis on cardiovascular causes of death. This study aimed to assess seasonal variations in mortality, in relation to clinical and laboratory variables in a large cohort of chronic hemodialysis patients over a 5-year period.Design, setting, participants, & measurements This study included 15,056 patients of 51 Renal Research Institute clinics from six states of varying climates in the United States. Seasonal differences were assessed by chi-squared tests and univariate and multivariate cosinor analyses.Results Mortality, both all-cause and cardiovascular, was significantly higher during winter compared with other seasons (14.2 deaths per 100 patient-years in winter, 13.1 in spring, 12.3 in autumn, and 11.9 in summer). The increase in mortality in winter was more pronounced in younger patients, as well as in whites and in men. Seasonal variations were similar across climatologically different regions. Seasonal variations were also observed in neutrophil/lymphocyte ratio and serum calcium, potassium, and platelet values. Differences in mortality disappeared when adjusted for seasonally variable clinical parameters. ConclusionsIn a large cohort of dialysis patients, significant seasonal variations in overall and cardiovascular mortality were observed, which were consistent over different climatic regions. Other physiologic and laboratory parameters were also seasonally different. Results showed that mortality differences were related to seasonality of physiologic and laboratory parameters. Seasonal variations should be taken into account when designing and interpreting longitudinal studies in dialysis patients.

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Section: Discussionsupporting

confidence: 91%

Seasonal Variations in Mortality, Clinical, and Laboratory Parameters in Hemodialysis Patients

Usvyat

Carter

Thijssen

et al. 2012

Clinical Journal of the American Society of Nephrology

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“…Similar findings for predialysis BP were noted in studies of 16 patients in Brazil (19), 102 patients in Uruguay (20), 53 patients in France (18), 144 patients in Japan (21), and the 1416 patients in this study (Table 1). Plausible mechanisms for the lower BP in the summer include decreased interdialytic fluid gain and thus decreased intravascular volume during that season.…”

Section: Variations In Bpsupporting

confidence: 90%

Seasonal Variations in Clinical and Laboratory Variables among Chronic Hemodialysis Patients

Cheung

Gao

Greene

et al. 2002

Journal of the American Society of Nephrology

105

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Abstract. Seasonal variations in BP among chronic hemodialysis patients have been reported. It was hypothesized that other characteristics of these patients might also vary with the seasons. Twenty-one clinical and laboratory variables were examined for seasonal variations among 1445 patients enrolled in the Hemodialysis Study, sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases. Mixed-effects models were applied to longitudinal changes (up to 45 mo) for individual patients for 19 of the 21 variables, which were measured at least twice each year, to determine the seasonal component of each variable. Seasonal variations in the other two variables, i.e., protein and energy intakes determined from annual dietary records, were assessed in cross-sectional comparisons of intakes of patients entering the study at different time points. Thirteen of the 21 variables examined demonstrated statistically significant (P Ͻ 0.01) seasonal components in their longitudinal variations. Predialysis blood urea nitrogen concentrations peaked in March, which coincided approximately with the peak protein catabolic rates, as well as protein and energy intakes (determined by dietary recall). Predialysis systolic and diastolic BP values were highest in winter and lowest in summer, corroborating previous reports. In addition, the lower predialysis BP values in summer were associated with higher outdoor temperatures and less interdialytic fluid gain. The mean predialysis hematocrit values were highest in July, which could not be attributed solely to the estimated changes in plasma volume. Seasonal variations in clinical and laboratory variables occur commonly among chronic hemodialysis patients. The reasons for most of these variations are not apparent and require further investigation. Nonetheless, failure to consider these variations might lead to biases in the interpretation of clinical studies. In addition, awareness of these variations might facilitate the interpretation of laboratory results and the clinical treatment of these patients.Normal cell physiologic processes (1), body composition (2,3), organ function (4 -8), clinical laboratory test results (9 -14), and disease processes (15-17) have all been demonstrated to be subject to seasonal variations in the general population. In particular, BP undergoes cyclic changes that are inversely correlated with outdoor temperatures, with peak levels in winter and the nadir in summer (2,4 -7). Seasonal variations in predialysis BP were recently observed among chronic hemodialysis patients on three different continents, encompassing both hemispheres, i.e., Europe, South America, and Asia (18 -21). The magnitudes of the reported seasonal changes were as great as 12 mmHg for systolic pressure and 7 mmHg for diastolic pressure in one study (18). Similar to findings for the general population, BP values for the dialysis patients in three of those studies (18,19,21) were inversely correlated with outdoor temperatures, with the highest mean BP occurring in the winter...

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“…It is therefore likely that any relationship between season and BP that has been reported heretofore may be not only to temperature but also to the effects of other associated factors related to season. [7][8][9] Environment-related BP variability is indeed a dynamic phenomenon, including short-term and long-term fluctuations which cannot be adequately assessed by studies focusing on air temperature only. 10 Devices that able to allow personal-level environmental temperature (PET) monitoring are now available, and the possibility to combine ambulatory BP (ABP) monitoring with continuous recording of air temperature at the subject's level might give an insight.…”

mentioning

confidence: 99%

Seasonal Blood Pressure Changes

Modesti

Morabito²,

Massetti³

et al. 2013

Hypertension

140

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P revious studies of the relationship between seasonality and blood pressure (BP), showing higher values in winter than in summer [1][2][3] , have relied on measures of ambient temperature. [4][5][6] However, this is an unreliable marker given that people generally spend most of their time indoors in regulated environments where the temperature is held constant. It is therefore likely that any relationship between season and BP that has been reported heretofore may be not only to temperature but also to the effects of other associated factors related to season.7-9 Environment-related BP variability is indeed a dynamic phenomenon, including short-term and long-term fluctuations which cannot be adequately assessed by studies focusing on air temperature only. 10 Devices that able to allow personal-level environmental temperature (PET) monitoring are now available, and the possibility to combine ambulatory BP (ABP) monitoring with continuous recording of air temperature at the subject's level might give an insight.The present study was thus prospectively designed to investigate the independent contribution of PET, and seasonality, expressed by daylight hours, on 24-hour systolic BP (SBP), daytime BP, nighttime BP, and morning BP surge in subjects referred to a hypertension unit. Methods SubjectsOutpatients referred for ABP monitoring to the Hypertension Clinics of the Clinica Medica of the University of Florence and of the Istituto Auxologico Italiano, University of Milano-Bicocca, from May 2005 to February 2007, were considered for the study. Inclusion criteria were availability of both clinic and ABP measurements; ABP recordings of good quality according to predefined criteria (≥80% of valid readings, ≥2 valid measurements per hour during daytime, and ≥1 valid measurement per hour during nighttime); data on age, sex, height, weight, and antihypertensive treatment; properly filled-in log book reporting working activities during the daytime and sleeping times. Subjects affected by clinically manifest cardiovascular or systemic diseases or those with altered nighttime sleep either because of shift work or disturbed by the ABP recording were excluded. Accordingly, we excluded 82 subjects from the study because their ABP recordings covered <20 hours or because a lower than the present number of measurements was available 11 ; 107 subjects because of incomplete data collection; 34 subjects because their sleep was severely disturbed by the ABP recording; and 18 subjects because ABP monitoring was performed while they were engaged in night work shifts. Therefore, a total of 1897 outpatients were investigated after obtaining their written informed consent (Table 1). The study was approved by our institutional review committees and adheres to the principles of the Declaration of Helsinki and Title 45, US Code of Abstract-Seasonal blood pressure (BP) changes have been found to be related to either outdoor or indoor temperature.No information regarding the independent effects of temperature measured proximally to the patient,...

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Seasonal variations of blood pressure and overhydration in patients on chronic hemodialysis

Cited by 37 publications

References 19 publications

Seasonal Variations in Mortality, Clinical, and Laboratory Parameters in Hemodialysis Patients

Seasonal Variations in Mortality, Clinical, and Laboratory Parameters in Hemodialysis Patients

Seasonal Variations in Clinical and Laboratory Variables among Chronic Hemodialysis Patients

Seasonal Blood Pressure Changes

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