Nutritional counseling regulates interdialytic weight gain and blood pressure in outpatients receiving maintenance hemodialysis

OUP accepted manuscript

Patients on chronic hemodialysis are counseled to reduce dietary sodium intake to limit their thirst and consequent interdialytic weight gain (IDWG), chronic volume overload and hypertension. Low-sodium dietary trials in hemodialysis are sparse and mostly indicate that dietary education and behavioral counseling are ineffective in reducing sodium intake and IDWG. Additional nutritional restrictions and numerous barriers further complicate dietary adherence. A low-sodium diet may also reduce tissue sodium, which is positively associated with hypertension and left ventricular hypertrophy. A potential alternative or complementary approach to dietary counseling is home delivery of low-sodium meals. Low-sodium meal delivery has demonstrated benefits in patients with hypertension and congestive heart failure but has not been explored or implemented in patients undergoing hemodialysis. The objective of this review is to summarize current strategies to improve volume overload and provide a rationale for low-sodium meal delivery as a novel method to reduce volume-dependent hypertension and tissue sodium accumulation while improving quality of life and other clinical outcomes in patients undergoing hemodialysis.

Pilot study to reduce interdialytic weight gain by provision of low-sodium, home-delivered meals in hemodialysis patients

INTRODUCTION

Patients with kidney failure undergoing maintenance hemodialysis (HD) therapy are routinely counseled to reduce dietary sodium intake to ameliorate sodium retention, volume overload, and hypertension. However, low-sodium diet trials in HD are sparse and indicate that dietary education and behavioral counseling are ineffective in reducing sodium intake. This study aimed to determine whether 4 weeks of low-sodium, home-delivered meals in HD patients reduces interdialytic weight gain (IDWG). Secondary outcomes included changes in dietary sodium intake, thirst, xerostomia, blood pressure, volume overload, and muscle sodium concentration.

METHODS

Twenty HD patients (55 ± 12 years, body mass index [BMI] 40.7 ± 16.6 kg/m² ) were enrolled in this study. Participants followed a usual (control) diet for the first 4 weeks followed by 4 weeks of three low-sodium, home-delivered meals per day. We measured IDWG, hydration status (bioimpedance), standardized blood pressure (BP), food intake (3-day dietary recall), and muscle sodium (magnetic resonance imaging) at baseline (0 M), after the 4-week period of usual diet (1 M), and after the meal intervention (2 M).

FINDINGS

The low-sodium meal intervention significantly reduced IDWG when compared to the control period (-0.82 ± 0.14 kg; 95% confidence interval, -0.55 to -1.08 kg; P < 0.001). There were also 1 month (1 M) to 2 month (2 M) reductions in dietary sodium intake (-1687 ± 297 mg; P < 0.001); thirst score (-4.4 ± 1.3; P = 0.003), xerostomia score (-6.7 ± 1.9; P = 0.002), SBP (-18.0 ± 3.6 mmHg; P < 0.001), DBP (-5.9 ± 2.0 mmHg; P = 0.008), and plasma phosphorus -1.55 ± 0.21 mg/dL; P = 0.005), as well as a 0 M to 2 M reduction in absolute volume overload (-1.08 ± 0.33 L; P = 0.025). However, there were no significant changes in serum or tissue sodium (all P > 0.05).

DISCUSSION

Low-sodium, home-meal delivery appears to be an effective method for improving volume control and blood pressure in HD patients. Future studies with larger sample sizes are needed to examine the long-term effects of home-delivered meals on these outcomes and to assess cost-effectiveness.

Thirst in patients on chronic hemodialysis: What do we know so far?

Thirst has been defined as "the sensation that leads animal's and human's actions toward the goal of finding and drinking water" or as "any drive that can motivate water intake, regardless of cause". Thirst, together with xerostomia, is the main cause of poor adherence to fluid restriction and of excessive intake of fluids in patients on chronic hemodialysis, and consequently of high interdialytic weight gain. Interdialytic weight gain (IDWG) should be lower than 4.0-4.5% of dry weight. Unfortunately, many patients have an IDWG greater than this value and some have IDWG of 10-20%. High IDWG is associated with a higher risk of all-cause and cardiovascular death and increased morbidity, such as ventricular hypertrophy and major adverse cardiac and cerebrovascular events. In addition, high IDWG leads to supplementary weekly dialysis sessions with consequent deterioration of quality of life and increased costs. Thus, the knowledge of thirst in patients on chronic hemodialysis is essential to prompt its adequate management to limit IDWG in the routine clinical practice. The present review aims to describe the physiology of thirst in patients on chronic hemodialysis, as well as the prevalence, its measures, the associated variables, the consequences, and the strategies for its reduction.

Dietary Daily Sodium Intake Lower than 1500 mg Is Associated with Inadequately Low Intake of Calorie, Protein, Iron, Zinc and Vitamin B1 in Patients on Chronic Hemodialysis

Background: To measure daily sodium intake in patients on chronic hemodialysis and to compare the intake of nutrients, minerals, trace elements, and vitamins in patients who had a daily sodium intake below or above the value of 1500 mg recommended by the American Heart Association. Methods: Dietary intake was recorded for 3 days by means of 3-day diet diaries in prevalent patients on chronic hemodialysis. Each patient was instructed by a dietitian on how to fill the diary, which was subsequently signed by a next of kin. Results: We studied 127 patients. Mean sodium intake (mg) was 1295.9 ± 812.3. Eighty-seven (68.5%) patients had a daily sodium intake <1500 mg (group 1) and 40 (31.5%) ≥ 1500 mg (group 2). Correlation between daily sodium intake and daily calorie intake was significant (r = 0.474 [0.327 to 0.599]; p < 0.0001). Daily calorie intake (kcal/kg/day) was lower in group 1 (21.1 ± 6.6; p = 0.0001) than in group 2 (27.1 ± 10.4). Correlation between daily sodium intake and daily protein intake was significant (r = 0.530 [0.392 to 0.644]; p < 0.0001). The daily protein intake (grams/kg/day) was lower in group 1 (0.823 ± 0.275; p = 0.0003) than in group 2 (1.061 ± 0.419). Daily intake of magnesium, copper, iron, zinc, and selenium was significantly lower in group 1 than in group 2. Daily intake of vitamin A, B2, B3, and C did not differ significantly between group 1 and group 2. Daily intake of vitamin B1 was significantly lower in group 1 than in group 2. Significantly lower was, in group 1 than in group 2, the percentage of patients within the target value with regard to intake of calories (11.5% vs. 37.5%; p = 0.001) and proteins (9.2% vs. 27.5%; p = 0.015) as well as of iron (23% vs. 45%; p = 0.020), zinc (13.8% vs. 53.8%; p = 0.008) and vitamin B1 (8.1% vs. 50%; p < 0.001). Conclusion: A low daily intake of sodium is associated with an inadequately low intake of calorie, proteins, minerals, trace elements, and vitamin B1. Nutritional counselling aimed to reduce the intake of sodium in patients on chronic hemodialysis should not disregard an adequate intake of macro- and micronutrients, otherwise the risk of malnutrition is high.

Quality of life on hemodialysis and inflammation: a descriptive analysis

Chronic kidney disease (CKD) is highly prevalent worldwide. Patients with CKD on hemodialysis are more likely to present behavioral changes and worse quality of life as a result of their routine and complications. They also have higher levels of cytokines. The aim of this study is to assess the relationship between the inflammatory profile and quality of life measured by KDOQL-SF36 in hemodialysis outpatients. Patients older than 21 years of age and on routine hemodialysis for at least 6 months with treatment on a regular weekly basis were included and their anthropometric parameters and serum inflammatory markers were evaluated. Thirty patients consented to participate. Homocysteine (Hcy) levels were correlated with worse glomerular filtration rate (GFR; P=0.003) and creatinine (P=0.002). IL-6 was not correlated with worse nutritional status taking into account body mass index (BMI; kg/m²; P=0.83). On the other hand, TNF-alpha was positively correlated with albumin (P=0.008), nutritional status by BMI (P=0.04), and nutritional status by arm circumference area (P=0.04). IL-6 was correlated with activity limitation (P=0.02) and Hcy with work status (P=0.04). Hcy was correlated with nutritional status and inflammatory markers. In this population, the majority of the sections in KDOQL-SF36 were not correlated with cytokines levels.