Diet and dialysis to control hypertension in patients on dialysis

Siddharth Venkat Ramanan; Madhusri Babu; Milly Mathew; Marina Alex; KN Preethi; Georgi Abraham

doi:10.4103/jrnm.jrnm_7_21

ORIGINAL ARTICLE

Year : 2020 | Volume : 6 | Issue : 4 | Page : 85-88

Diet and dialysis to control hypertension in patients on dialysis

Siddharth Venkat Ramanan¹, Madhusri Babu¹, Milly Mathew², Marina Alex², KN Preethi¹, Georgi Abraham²
¹ Department of Nephrology, The Madras Medical Mission Hospital, Chennai, Tamil Nadu, India
² Department of Nephrology, MGM Healthcare, Chennai, Tamil Nadu, India

Date of Submission	04-Feb-2021
Date of Acceptance	01-Mar-2021
Date of Web Publication	20-Jul-2021

Correspondence Address:
Dr. Georgi Abraham
MGM Healthcare, Chennai 600 029, Tamil Nadu
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jrnm.jrnm_7_21

Abstract

Introduction: Uncontrolled hypertension in hemodialysis (HD) patients is related to a variety of causes, of which dietary salt intake plays a major role. Excessive interdialytic weight gain (IDWG) with accompanying hypertension can lead to increase cardiovascular morbidity and mortality. Materials and Methods: We conducted a cross-sectional observational study to assess the prevalence of hypertension among patients on maintenance HD (MHD) and its relationship with daily sodium intake. We included participants who were getting MHD at out tertiary care center and in whom a digital brachial blood pressure (BP) was measured. Results: Of the 118 patients studied, 73 (61.9%) were male. AVF was the access for HD in 88 (74.6%) patients, 22 (18.6%) patients were getting HD through a permcath, and the rest through a temporary central venous HD catheter. HD was being done once a week for 3 (2.5%) patients, 80 (67.8%) patients were getting HD twice a week, and the others thrice a week. The mean pre-HD BP was 151.7/80 ± 22.55/12.8 mmHg, and the mean post-HD BP was 168/90.9 ± 23.7/11.3 mmHg. An IDWG of <2 kg was seen in 32 (32.2%) patients; the remaining patients had an IDWG of >2 kg. The mean IDWG was 2.41 kg. Seventeen (14.4%) patients were not on any antihypertensive medications, 48 (40.7%) patients were taking 1–2 antihypertensive drugs, and the rest were on >3 antihypertensive drugs. A urine output of <100 ml/day was present in 45 (38.1%) patients; the rest had a daily urine output of over 100 ml up to 1000–1200 ml. Nutritional assessment by a trained dietician showed that sodium intake ranged from 1700 mg to 2200 mg/day. Conclusion: Dietary sodium intake was controlled in our HD patients with the intake of 1700–2200 mg per day. The weight gain was excessive in 67.8% of our patients, Patients were ingesting 1–5 antihypertensive drugs of different classes and 14.4% were not on any antihypertensive drugs. Dialysis was being done twice a week for 67.8% of our patients and thrice a week for 29.7% of patients. We found hypertension in 85.6% of our cohort.

Keywords: Chronic kidney disease, hemodialysis, hypertension, sodium

How to cite this article:
Ramanan SV, Babu M, Mathew M, Alex M, Preethi K N, Abraham G. Diet and dialysis to control hypertension in patients on dialysis. J Renal Nutr Metab 2020;6:85-8

How to cite this URL:
Ramanan SV, Babu M, Mathew M, Alex M, Preethi K N, Abraham G. Diet and dialysis to control hypertension in patients on dialysis. J Renal Nutr Metab [serial online] 2020 [cited 2023 May 28];6:85-8. Available from: http://www.jrnm.in/text.asp?2020/6/4/85/321989

Introduction

Hypertension is present in >80% of patients with chronic kidney disease.^[1] It is a risk factor for cardiovascular disease and all-cause mortality in patients on hemodialysis (HD). High blood pressure (BP) can lead to several cardiovascular changes, including left ventricular hypertrophy, diastolic heart failure, systolic heart failure, and hemorrhagic stroke. A variety of reasons are attributed to the increased incidence of hypertension in CKD patients-sodium retention, increased activity of the renin–angiotensin–aldosterone system, enhanced sympathetic nervous system activity, and treatment with erythropoiesis-stimulating agents (ESA).

The prevalence of hypertension in HD patients varies significantly between studies due to differences in the definitions of hypertension and in the methods of measuring BP. As such, 62%–86% of patients on HD are hypertensive.^[2],[3],[4] Intradialytic hypertension is essentially an increase in BP from pre- to post-HD and is associated with higher interdialytic ambulatory BPs and higher mortality.^[5] Its prevalence is estimated to be 5%–15%, and one study from India showed that 21.9% of HD patients had intradialytic hypertension.^[6],[7]

Dietary sodium restriction is an established nonpharmacological way to reduce BP. Sodium restriction plays a more significant role in oligo-anuric patients on maintenance HD (MHD) by limiting extracellular volume accumulation and controlling BP between dialysis sessions. However, lower salt intake is also associated with lower protein and calorie intake, leading to malnutrition, an independent risk factor for mortality and morbidity in HD patients.

Our study assesses patients' pre- and postdialysis and looks at their daily sodium intake and its relationship with hypertension, drug therapy, and weight gain. In the context of the sparsity of such studies from India, ours is a novel and unique endeavor.

Materials and Methods

Ethics statement

The study was conducted following the Institutional Ethics Committee's approval and was performed per the “Ethical Guidelines for Biomedical Research on Human Participants 2006” by the Indian Council of Medical Research and the Declaration of Helsinki. Written informed consent was obtained from patients before they participated in the study.

Selection and description of participants

This cross-sectional study was conducted among patients with CKD 5D currently on MHD. Dialysis vintage for these patients ranged from 1 month to 120 months. Conscious patients who consented to participate in the study and in whom brachial BP was measurable at the dialysis center were included. Patients who did not agree to participate in the study or in whom brachial BP was not measurable were excluded from the study. Patients were approached during scheduled HD visits, and consent to participate in the study was obtained. One hundred eighteen patients participated in the study. These patients had regular nutrition counseling by a skilled person in the dialysis unit once in 2–4 weeks, depending on their salt intake and weight gain. These patients were on either short-acting or long-acting ESAs (epoetin alpha, darbepoetin alpha, methoxy polyethylene glycol-epoetin beta)

Data collection

Data were collected using a standardized questionnaire. Information gathered included age, gender, duration of HD, HD access, frequency of HD (sessions/week), daily urine output, interdialytic weight gain (IDWG), brachial BP just before starting dialysis and just after dialysis was stopped, and daily sodium intake using 24 h dietary recall. All patients had a two-dimensional echocardiogram done at the initiation of dialysis and periodically in those with uncontrolled BP.

Results

The age composition and dialysis vintage of our patients are given in [Table 1]. Of the 118 patients studied, 73 (61.9%) were male. AVF was the access for HD in 88 (74.6%) patients. Twenty-two (18.6%) patients were getting HD through a permcath and the rest through a temporary central venous HD catheter. HD was being done once a week for 3 (2.5%) patients, 80 (67.8%) patients were getting HD twice a week, and the others thrice a week. The mean pre-HD BP ± SD was 151.7/80 ± 22.55/12.8, and the mean post-HD BP ± SD was 168/90.9 ± 23.7/11.3. An IDWG of <2 kg was seen in 32 patients; the remaining patients had an IDWG of >2 kg. The mean IDWG was 2.41 kg. Seventeen (14.4%) patients were not on any antihypertensive medications, 48 (40.7%) patients were taking 1–2 antihypertensive drugs, and the rest were on >3 antihypertensive drugs. In decreasing frequency, the antihypertensive drugs were calcium channel blockers, beta-blockers, centrally acting sympatholytic, vasodilators, high-dose furosemide, ACE inhibitors, ARBs, and aldosterone antagonists. A urine output of <100 ml/day was present in 45 (38.1%) patients; the rest had a daily urine output of over 100 ml up to 1000–1200 ml. Nutritional assessment by a trained dietician showed that sodium intake ranged from 1700 mg^-2200 mg/day.

Table 1: Age composition and dialysis vintage

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[Figure 1] shows the body composition monitor result of a 33-year-old nondiabetic, anuric male with a dialysis vintage of 10 months. He was getting dialysis three times a week, with each session lasting for around 4 h, and was getting an ESA once a week. He had a mean IDWG-2.6 kg. His mean BP over the last three visits was 177/118 mmHg, and he took four antihypertensive drugs suggesting treatment-resistant hypertension. His body mass index-20.8 kg/m²). We use polyethersulfone-1.4 m² dialyzers, which have an ultrafiltration coefficient of 12 ml/h/mmHg/m².

Figure 1: Body composition monitor composition of a treatment-resistant hypertensive dialysis patient

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Discussion

There is no gold standard for BP measurement in MHD patients. However, in patients on MHD, the BP should not exceed 140/90 mmHg so as to reduce cardiovascular complications. Literature review shows differences in international guidelines regarding the setting (home vs. dialysis center) of BP measurement. The BOLD (Blood pressure Lowering in Dialysis) study, DRIP (Dry-weight reduction in Hypertensive Hemodialysis Patients) study, BID (BP in dialysis), BLOCADE (B-blocker to Lower Cardiovascular Dialysis Events), and HDPAL study (Hypertension in Hemodialysis treated with Atenolol or Lisinopril) all looked at BP measurement at various settings and time intervals in MHD patients.^[8] The home BP monitoring (HBPM) is an established technique recommended by international guidelines.^[9],[10] HBPM has been shown to better reflect target organ damage and all-cause mortality.^[11] Home BP measurements were taken twice a day for at least 3 days, preferable 7 days, may reliably be used in the initial evaluation and treatment of hypertension.

In our cohort of patients, 14.4% were not on antihypertensive therapy as their measured BP was <140/90 mmHg. The mean pre- and postdialysis BP was 151.7/80 ± 22.55/12.8 mmHg and 168/90.9 ± 23.7/11.3 mmHg, respectively, and sodium consumption varied between '1700 and 2200 mg per day. The most common echocardiogram finding in our patients was left ventricular hypertrophy with diastolic dysfunction suggesting long-term hypertension. A single-center study by Kale et al. with 120 Indian patients showed higher morbidity and mortality among those patients with intradialytic hypertension.^[7]

As the causes of hypertension in dialysis patients are multifactorial despite dry weight achievement, antihypertensive drugs, and ESA use, it is difficult to pinpoint a specific cause and effect relationship. In end-stage kidney disease (ESKD), dialysis remains the only effective means to remove dietary sodium. The mismatch between intake and removal of sodium leads to fluid overload, hypertension, and left ventricular hypertrophy, worsening ESKD patients' prognosis. The WHO recommends a daily sodium intake of <2.3 g per day.^[12] In our dialysis patients, the sodium intake ranged from 1700 to 2200 mg per day. Several studies have explored the effect of lower sodium dialysate concentrations on BP. Although there is a reduction in ambulatory BP and IDWG, they have found no benefit with regard to health-related quality of life measures; in fact, there was an increased incidence of symptomatic intradialytic hypotension.^[13],[14] The concentration of sodium in our dialysate is 140 meEq/L. The extended dialysis as a home therapy 5–6 days a week has shown better control of BP and reduction in the intake of antihypertensives medication.^[15]

Limitations of the study

The limitations of the study are cross sectional in nature, lack of HBPM and ABP measurements, and ESA effect on BP.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1.	Whaley-Connell AT, Sowers JR, Stevens LA, McFarlane SI, Shlipak MG, Norris KC, et al. CKD in the United States: Kidney Early Evaluation Program (KEEP) and National Health and Nutrition Examination Survey (NHANES) 1999-2004. Am J Kidney Dis 2008;51 4 Suppl 2:S13-20.
2.	Iseki K, Nakai S, Shinzato T, Morita O, Shinoda T, Kikuchi K, et al. Prevalence and determinants of hypertension in chronic hemodialysis patients in Japan. Ther Apher Dial 2007;11:183-8.
3.	Rahman M, Dixit A, Donley V, Gupta S, Hanslik T, Lacson E, et al. Factors associated with inadequate blood pressure control in hypertensive hemodialysis patients. Am J Kidney Dis 1999;33:498-506.
4.	Agarwal R, Nissenson AR, Batlle D, Coyne DW, Trout JR, Warnock DG. Prevalence, treatment, and control of hypertension in chronic hemodialysis patients in the United States. Am J Med 2003;115:291-7.
5.	Van Buren PN, Inrig JK. Mechanisms and Treatment of Intradialytic Hypertension. In: Blood Purification [Internet]. S. Karger AG; 2016. p. 188–93. Available from: /pmc/articles/PMC4854275/?report=abstract. [cited 2021 Feb 2].
6.	Van Buren PN, Kim C, Toto R, Inrig JK. Intradialytic hypertension and the association with interdialytic ambulatory blood pressure. Clin J Am Soc Nephrol 2011;6:1684-91.
7.	Kale G, Mali M, Bhangale A, Somani J, Jeloka T. Intradialytic hypertension increases non-access related hospitalization and mortality in maintenance hemodialysis patients. Indian J Nephrol 2020;30:85. [Full text]
8.	Georgianos PI, Agarwal R. Can we study hypertension in patients on dialysis? Yes we can. Am J Kidney Dis 2021;77:4-6.
9.	Williams B, Mancia G, Spiering W, Rosei EA, Azizi M, Burnier M, et al. 2018 ESC/ESHGuidelines for themanagement of arterial hypertension. J Hypertens 2018;30:1956-2041.
10.	Whelton PK, Carey RM, Aronow WS, Casey DE, Collins KJ, Himmelfarb CD, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: Executive summary: A report of the American college of cardiology/American Heart Association task force on clinical practice guidelines. Hypertension 2018;71:1269-324.
11.	Agarwal R, Andersen MJ, Light RP. Location not quantity of blood pressure measurements predicts mortality in hemodialysis patients. Am J Nephrol 2008;28:210-7.
12.	WHO. Sodium Intake for Adults and Children [Internet]. Guideline: Sodium Intake for Adults and Children 2012. Available from: http://www.ncbi.nlm.nih.gov/pubmed/23658998. [cited 2021 Feb 3].
13.	Dunlop JL, Vandal AC, Marshall MR. Low dialysate sodium levels for chronic haemodialysis [Internet]. Vol. 2019, Cochrane Database of Systematic Reviews. John Wiley and Sons Ltd; 2019. Available from: HYPERLINK “https://pubmed.ncbi.nlm.nih.gov/30646428/”Low dialysate sodium levels for chronic haemodialysis - PubMed. [cited 2021 Feb 3].
14.	Marshall MR, Vandal AC, De Zoysa JR, Gabriel RS, Haloob IA, Hood CJ, et al. Effect of low-sodium versus conventional sodium dialysate on left ventricular mass in home and self-care satellite facility hemodialysis patients: A randomized clinical trial. Am Soc Nephrol 2020;31:1078-91.
15.	Kotanko P, Garg AX, Depner T, Pierratos A, Chan CT, Levin NW, et al. Effects of frequent hemodialysis on blood pressure: Results from the randomized frequent hemodialysis network trials. Hemodial Int 2015;19:386-401.