EAL

HESI: Congestive Heart Failure Population (2014)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine the effects of a sodium-resricted DASH diet on human hypertensive HF with preserved ejection fraction.

Inclusion Criteria:

History of systemic hypertension, left ventricular ejection fraction at or above 50%, evidence of ventricular diastolic dysfunction.

Exclusion Criteria:

New York Heart Association class IV symptoms
Prior history of left ventricular ejection fraction less than 40%
Hospitalization within past one month
Systolic BP greater than 180mmHg at rest on current regimen
Severe renal insufficiency (estimated GFR less than 30ml per minute per 1.73m²
Serum potassium greater than 5.0mmol per L (or previously at least 6.0mmol per L)
Moderate or worse mitral or aortic stenosis or insufficiency
Severe anemia (hemoglobin less than nine grams per dL)
Exercise capacity limited due to pulmonary disease
Uncontrolled diabetes mellitus (hemoglobin A1C greater than 9%)
Medication changes for hypertension or heart failure within past month.

Description of Study Protocol:

Recruitment: Not described
Design: Before/after study; over 25 days with two days of testing before and after the 21st day of DASH/SRD
Intervention: DASH/SRD; all foods provided beginning on Day Three. Sodium intake, 50mmol per 2,100kcal. Adherence assessed with three-day food records at mid-point and pre- and post-diet 24-hour urinary sodium and potassium excretion.
Statistical analysis: Paired T-tests and Wilcoxon rank-sum tests were used for continuous and ordinal variables, repsectively, with P<0.05 denoting statistical significance.

Data Collection Summary:

Timing of Measurements

24-hour urinary sodium and potassium excretion pre- and post-diet
Diet assessed at baseline with FFQ; three-day food record at mid-point to assess compliance
Pre and post dietary measures for all variables.

Dependent Variables

BP
Urinary F2 isoprostaines
Six-minute walk test at baseline
Transthoracic echocardiography
Serum sodium, potassium, creatinine, urea nitrogen
24-hour urinary sodium, potassium, creatinine clearance.

Independent Variables

DASH/SRD for 21 days.

Control Variables

All food and beverages provided.

Description of Actual Data Sample:

Initial N: 14 (13 female, one male)
Attrition (final N): 13
Age: 72±10 years
Ethnicity: Not described
Anthropometrics: BMI, 35.5±7.9kg/m²
Location: Michagan, USA.

Summary of Results:

Key Findings

The DASH/SRD reduced both clinic (155 to 138/79 to 72) and ambulatory (130 to 123/67 to 62) SBP and DBP (all P=0.02)
Urinary F2-isoprostanes decreased by 31% (P=0.02), which was correlated with reduced urinary sodium excretion (R=0.76, R=0.002), but not urinary aldosterone (R=-0.19; P=0.57).

Other Findings

Variable	Pre-Dietary	Post-Dietary	P-Value
Serum Sodium, mmol/L	141±3	139±3	0.07
Serum Potassium, mmol/L	4.5±0.4	4.6±0.6	0.46
Serum Creatinine, mg/dL	1.0±0.2	1.2±0.3	0.02
Serum urea nitrogen, mg/dL	28±13	41±24	0.03
24-hour creatinine clearance, ml/minute per 1.73m²	66±35	57±30	0.11
24-h urinary sodium, mg/24 hours	3,353±1593	1,478±933	<0.001
24-h urinary potassium, mg/24 hours	2,284±793	2,925±1024	0.04

Author Conclusion:

Three weeks of DASH/SRD significantly reduced clinic and ambulatory BP, arterial stiffness and oxidative stress. These observations are characteristic of salt-sensitive hypertension.

Funding Source:

Government:	NIH
Other:	Innovations in Cardiovascular Medicine

Reviewer Comments:

Additional Quality Table for Intervention Studies

What was the baseline nutrient status (i.e., sodium)? For example the baseline sodium status can be used as an inclusion criterion for entry into study and recorded in the report of the trial.	Serum Na (P=0.07) Pre-dietary:141±3mmol per L Post-dietary:139±3mmol per L
Was the difference in sodium intake measured between groups? If so, please specify.	Baseline: 3,262.86±1,238.0 DASH/SRD: 1,449.83±367.8
Was the difference in sodium status (i.e., change in urinary sodium excretion) measured between groups? If so, please specify.	24-hour urinary sodium (P<0.001) Pre-dietary: 3,353±1,593mg per 24 hours Post-dietary: 1,478±933mg per 24 hours
Was the status of other nutrient (e.g., potassium and calcium) measured in order to ensure that the test nutrient (i.e., sodium) is the only nutrition-related, limiting factor in the response? If yes, please specify.	24-hour urinary potassium (P=0.04) Pre-dietary: 2,284±793mg per 24 hours Post-dietary: 2,925±1,024mg per 24 hours

Not generalizable to all heart failure with preserved ejection fraction (HFPEF) patients such as those with non-hypertensive pathogenesis or different demographics
Short-term results; long-term studies needed
The component of the diet (sodium reduction, potassium and antioxidant increase) that contributed with the results.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
3.	Were study groups comparable?		N/A
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	N/A
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	N/A
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	Yes
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	N/A
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	Yes
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	N/A
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		N/A
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	N/A
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	N/A
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	Yes
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	Yes
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	Yes
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	N/A
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	N/A
	8.6.	Was clinical significance as well as statistical significance reported?	N/A
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes