Review: Blood pressure in haemodialysis patients: The importance of the relationship between the renin-angiotensin-aldosterone system, salt intake and extracellular volume

Paradoxical Association Between Intradialytic Blood Pressure Change and Long-Term Mortality with Different Levels of Interdialytic Weight Gain

Background

A greater interdialytic weight gain (IDWG) implies a greater ultrafiltration rate, which might lead to hemodynamic instability and intradialytic blood pressure (BP) change in hemodialysis patients. However, current studies have not explicated the impact of IDWG on the association between intradialytic BP changes and prognosis, especially in patients without cardiac dysfunction and diabetes. In this study, we aimed to explore the relationship between absolute intradialytic BP changes and mortality with different IDWG levels.

Methods

A total of 204 hemodialysis patients (without cardiac dysfunction and diabetes) were included in this prospective observation study, with a mean follow-up of 55.32±20.99 months. Initially, we collected IDWG, IDWG% (percentages according to dry weight), and pre-/post-BPs of 36 consecutive dialysis sessions during three months enrollment. And the average value of them was defined as baseline value. Patients were divided into 3 cohorts according to IDWG% tertiles (<3.3%, 3.3%-4.6%, ≥4.6%). Comparisons between different tertiles were analyzed.

Results

Compared to the low IDWG% group (tertile 1, T1), patients of high IDWG% group (tertile 3, T3) were younger, had higher ultrafiltration rate, less residual kidney function, lower BMI and dry weight, longer dialysis vintage and higher N terminal pro B type natriuretic peptide levels (P<0.05). Correlations were found between IDWG% and intradialytic BP changes. Kaplan-Meier analysis and multivariate Cox regression model adjusted for demographic data, dialysis information and predialysis BPs indicated that greater absolute intradialytic BP changes were associated with worse prognosis in T1 group (P<0.05). While in T3 group, less absolute intradialytic BP changes were associated with higher mortality (P<0.05).

Conclusion

There is a paradoxical association between absolute intradialytic BP changes and long-term mortality with different IDWG levels. Both BP stability and volume balance are crucial to patients' prognosis.

Health Beliefs Related to Salt-Restricted Diet and Associated Factors in Turkish Patients on Hemodialysis

Purpose: To examine health beliefs related to salt-restricted diet, to investigate their associations with demographic/disease-related characteristics and family support, and to determine the need for tailored interventions in Turkish patients on hemodialysis. Method: A cross-sectional study was conducted among 200 patients on hemodialysis. Data were collected through an information form, the Perceived Social Support from Family Scale and the Beliefs about Dietary Compliance Scale, including two subscales: perceived benefits and barriers. Descriptive statistics, Student’s t test, Pearson’s correlation coefficients, and linear regression analysis were used for data analysis. Results: The item mean perceived benefit score was higher than the item mean perceived barrier score. Limiting salt intake, family support, and the presence of residual urine output were associated with health beliefs. Conclusions/Implications: The likelihood of adherence to salt-restricted diet was high. A better understanding of health beliefs about salt-restricted diet and their related factors may facilitate the implementation of tailored interventions.

Safety and Efficacy of Losartan 50 mg in Reducing Blood Pressure among Patients with Post-Dialysis Euvolemic Hypertension: A Randomized Control Trial

The aim of current study was to assess the effectiveness of losartan 50 mg in reducing blood pressure among post-dialysis euvolemic hypertensive patients, observing their survival trends and adverse events during the course of study. A multicentre, prospective, randomised, single-blind trial was conducted to assess the effect of losartan 50 mg every other day (EOD), once a morning (OM) among post-dialysis euvolemic hypertensive patients. Post-dialysis euvolemic assessment was done by a body composition monitor (BCM). Covariate Adaptive Randomization was used for allocation of participants to the standard or intervention arm. Of the total 229 patients, 96 (41.9%) were identified as post-dialysis euvolemic hypertensive. Final samples of 88 (40.1%) patients were randomized into standard and intervention arms. After follow-up of 12 months’ pre-dialysis systolic (p < 0.001) and diastolic (p 0.01), intradialysis diastolic (p 0.02), post-dialysis systolic (p < 0.001) and diastolic (p < 0.001) blood pressure was reduced from the baseline among intervention-arm patients Compared to only pre-dialysis systolic blood pressure (p 0.003) among standard arm patients after 12 months of follow. Total of six deaths were reported among standard-arm patients compared to 2 deaths among the intervention arm. Losartan 50 mg achieve an overall significant decline in blood pressure among post-dialysis euvolemic hypertensive patients.