Diététique hyposodée chez le patient dialysé: mythe ou réalite?

Impact of salt reduction in meals consumed during hemodialysis sessions on interdialytic weight gain and hemodynamic stability

INTRODUCTION

Patients on hemodialysis (HD) are advised to limit daily water- and salt intake to reduce interdialytic weight gain (IDWG). To counterbalance protein-losses, protein-rich meals are sometimes provided during HD sessions, but their salt content is not always taken into account. The aim of this study was to assess the influence of a lower salt content of meals provided during HD sessions on IDWG, blood pressure (BP), and hemodynamic stability during dialysis.

METHODS

This monocentric, interventional study was proposed to all the patients treated with three weekly HD sessions. The first two months of the study (high salt period), the patients continued to receive one sandwich containing 2.4 g of salt per session. Then, we reduced its salt content from 2.4 to 1.4 g, and patients received this "low-salt sandwich" at each dialysis session for four months. The mean values of IDWG, BP, and dry weight of the first two months were compared with those collected during the low salt periods (2-6 months).

FINDINGS

Forty out of 76 patients who initially agreed to participate were free of hospitalization, transplantation, and transfer to another center or death during the study period and were included in the final analysis (35% women). Median age was 63 years (range 28-90), 22.5% had a residual diuresis > 0.5 L/day. IDWG baseline decreased from 2.17 ± 0.98 to 2.03 ± 1 kg (P = 0.001) two months and to 2.09 ± 1.01 kg (P = 0.009) four months after we had lowered the salt content of the sandwich. The number of symptomatic intradialytic hypotension was also reduced (6.1% vs., respectively, 3.2% and 3.3% of HD sessions; P = 0.004).

DISCUSSION

IDWG was reduced and hemodynamic stability improved after the reduction of the salt content of perdialytic meals. This suggests that salt consumed during HD matters and might influence salt and water intake outside the dialysis unit.

Modified Nutritional Recommendations to Improve Dietary Patterns and Outcomes in Hemodialysis Patients

The renal diet has traditionally been regarded as one of the most complex medical nutrition therapies to teach, understand, and implement. Specifically, patients are instructed to limit fruits, vegetables, nuts, legumes, dairy, and whole grains because of both phosphorus and potassium concerns. Furthermore, hemodialysis patients are often encouraged to decrease fluid intake to control interdialytic weight gain. These restrictions can result in frustration, lack of autonomy, and the perception that there is nothing left to eat. It is possible that the traditional renal diet may be liberalized, with a focus on whole foods low in sodium and phosphorus additives, to afford patients greater choices and ultimately improved outcomes. Therefore, the objective of this review is to concisely assess the evidence in support of a renal diet focused primarily on reducing the intake of sodium and inorganic phosphorus. Finally, the limited evidence for restrictions on dietary potassium intake is summarized.

Association of Processed Meat Intake with Hypertension Risk in Hemodialysis Patients: A Cross-Sectional Study

In this cross-sectional study, we hypothesized that hemodialysis patients consuming greater processed meat is associated with hypertension risk, which can be partly explained by the high sodium content in processed meat. From September 2013 to May 2014, one hundred and four patients requiring chronic hemodialysis treatment were recruited from hemodialysis centers. Data on systolic blood pressure and diastolic blood pressure before receiving dialysis, and 3-day dietary records of the recruited patients were collected. HD patients with systolic and diastolic blood pressures greater than140 mmHg and higher than 90 mmHg, respectively, were considered hypertension risk. Protein foods were divided into 4 categories: red meat, white meat, soybeans, and processed meat (e.g., sausage and ham). In a model adjusted for energy intake and hypertension history, additional servings of processed meats was positively associated to systolic blood pressure >140 mmHg (odds ratio [95% confidence interval]: 2.1 [1.0–4.3]), and diastolic blood pressure > 90 mmHg (odds ratio: 2.5 [1.2–5.5]). After adjustment for dietary sodium contents or body mass index (BMI), most associations were substantially attenuated and were no longer significant. In systolic blood pressure greater than140 mmHg, one serving per day of red meats (β = -1.22, P < .05) and white meats (β = -0. 75, P = .05) was associated with a reduced risk compared with one serving per day of processed meats. Similarly, compared with one serving per day of processed meat, a reduced risk of diastolic blood pressure higher than 90 mmHg was associated with one serving per day of red meat (β = -1. 59, P < .05), white meat (β = -0. 62, P < .05). Thus, in these hemodialysis patients, intake of processed meat is significantly positively associated with higher blood pressure risk, and both sodium contents in processed meat and BMI significantly contributes to this association.

Significance of interdialytic weight gain versus chronic volume overload: consensus opinion

Predialysis volume overload is the sum of interdialytic weight gain (IDWG) and residual postdialysis volume overload. It results mostly from failure to achieve an adequate volume status at the end of the dialysis session. Recent developments in bioimpedance spectroscopy and possibly relative plasma volume monitoring permit noninvasive volume status assessment in hemodialysis patients. A large proportion of patients have previously been shown to be chronically volume overloaded predialysis (defined as >15% above 'normal' extracellular fluid volume, equivalent to >2.5 liters on average), and to exhibit a more than twofold increased mortality risk. By contrast, the magnitude of the mortality risk associated with IDWG is much smaller and only evident with very large weight gains. Here we review the available evidence on volume overload and IDWG, and question the use of IDWG as an indicator of 'nonadherence' by describing its association with postdialysis volume depletion. We also demonstrate the relationship between IDWG, volume overload and predialysis serum sodium concentration, and comment on salt intake. Discriminating between volume overload and IDWG will likely lead to a more appropriate management of fluid withdrawal during dialysis. Consensually, the present authors agree that this discrimination should be among the primary goals for dialysis caretakers today. In consequence, we recommend objective measures of volume status beyond mere evaluations of IDWG.

Relationship between beliefs regarding a low salt diet in chronic renal failure patients on dialysis

OBJECTIVE

The aim of this study was to investigate the relationship between beliefs regarding a low salt diet and the nutritional behavior of sodium consumption as well their relation with sociodemographic and clinical variables among chronic renal failure (CRF) patients on dialysis.

DESIGN AND METHODS

This cross-sectional study enrolled a sample of 117 patients who answered the Brazilian version of the Beliefs about Dietary Compliance Scale (BDCS), the sodium frequency food questionnaire, and the use of discretionary salt/day.

RESULTS

The average of total salt consumption was 10.6 g/day (±6.3) and it was positively correlated with the interdialytic weight gain (r = 0.20 P = .032) and negatively correlated with the education level (r = -0.19 P = .044). The Benefits beliefs were discriminatory of the higher and lower salt consumers, and proportionally related to monthly income (r = 0.22 P = .017). The Barriers beliefs were positively correlated only to time on dialysis (r = 0.25 P = .008). Subjects with lower schooling and those of older age tended to consume more discretionary salt (r = -0.27, P = .005; r = 0.23, P = .016, respectively); however, they reported a lower consumption of foods with high salt content (r = 0.25 P = .006; r = -0.27 P = .004).

CONCLUSIONS

Educational interventions aimed at reducing salt consumption for this group must include interventions targeted at different behaviors related to overall salt consumption, the specificities of age, and level of schooling of the patients.