EAL

HESI: Congestive Heart Failure Population (2014)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To assess the ability of patients with asymptomatic to mildly symptomatic heart failure, and no signs or symptoms of congestion, to excrete ingested sodium and to identify possible early abnormalities of hormonal and hemodynamic mechanisms related to sodium handling.

Inclusion Criteria:

Chronic, stable, mild heart failure patients with no signs or symptoms of congestion
NYHA class I or II
Left ventricular ejection fraction under 50%.

Exclusion Criteria:

Angina pectoris
Myocardial infarction within previous three months
Hypertension
Atrial fibrillation or severe ventricular arrhythmias
Renal failure
Recent acute cardiac decompensation
Valvular disease or significant mitral regurgitation
Cardiothoracic anatomy not allowing satisfactory and reproducible recording of echocardiogram
Previous treatment with diuretics.

Description of Study Protocol:

Recruitment

Patients recruited in the outpatient clinic for treatment of cardiovascular disease
Recruitment for the normal volunteers was not reported.

Design
Single arm clinical trial.

Intervention

A control diet was administered for five days before intervention with a moderate sodium diet: 100mEq sodium and 50mEq potassium in the form of pasta, meat, eggs, bread, vegetables and fruit. Water intake was kept between 1,500ml and 1,800ml per day.
An intervention diet was administered for six days (after a control diet of five days): High-sodium diet with total sodium intake of 250mEq [100mEq sodium from diet plus 150mEq of sodium supplement (three 50-mEq supplements of crystalline sodium chloride, each wrapped in wafers administered during the three meals)]
Statistical analysis
- Distribution of data assessed by the Bartlett test
- X² analysis was used for comparison of descriptive parameters
- Comparison between different groups for the basal data was analyzed by unpaired T-test or Wilcoxon rank test, as appropriate
- One-way ANOVA for repeated measures followed by post-hoc comparisons within the same group
- Two-way ANOVA (factoring for group and time) for between-group comparisons of the responses
- Data presented as means ±SEM.

Data Collection Summary:

Timing of Measurements
The baseline measurements for biochemical and hormonal measurements were taken after the subjects had been on a moderate-sodium diet (100mEq per day) for five days. Urinary volume and electrolyte excretion were measured daily, while blood for biochemical and hormonal measurements were collected daily on Days Three through Six of the experimental period (one week) with high salt intake regimen.

Dependent Variables

Urinary sodium excretion: 24-hour urine
Plasma renin activity (PRA) and aldosterone concentrations.

Independent Variables

Sodium intake (high-salt diet).

Description of Actual Data Sample:

Initial N: 14 patients, 11 M/3F in the HF group; 13 normal subjects,10 M/3F in the normal group.

Attrition (final N): 12 patients; 9M/3F in the HF group ; 12 normal subjects,9M/3F.

Reasons for exclusion: Two patients were excluded due to lack of compliance with dietary sodium manipulation, and one normal subject for the same reason.

Age: HF group: 46+3y; Normal group: 38+4y.

Ethnicity: N/A

Anthropometrics: Body weight was similar between both groups.

Other relevant demographics: Three patients had received treatment with digitalis; nitrates were used in 5 patients before the study, and five patients had been treated with angiotensin converting enzyme inhibitors. All medications were discontinued 2 weeks previous to the beginning of the study.

Location: Napoli, Italy.

Summary of Results:

Key Findings

High salt diet increased urinary sodium excretion (UNa) in both normal subjects (F=24.2, P<0.001) and in HF patients (F=14.3, P<0.001). Response between the two groups were not significantly different (F=1.63, P=N.S).
Sodium retention was significantly more marked in HF patients when cumulative sodium balance was calculated (F=5.03, P<0.001) with high sodium intake.

Other Findings:

In normal subjects, high salt diet was associated with significant increases of echocardiographically measured left ventricular end-diastolic volume, ejection fraction, and stroke volume (P<0.001) and with a reduction of total peripheral resistance (P<0.001). In addition, plasma atrial natriuretic factor (ANF) levels was increased (P<0.05), whereas plasma renin activity and aldosterone were decreased (P<0.001)

In HF patients plasma renin activity and plasma aldosterone concentrations were suppressed during high salt intake (P<0.05 and P<0.001, respectively), and plasma ANF levels was not increased. In addition, both left ventricular end-diastolic (F=7.3,P<0.01) and end-systolic volumes (F=8.87,P<0.001) increased in response to high sodium diet, whereas ejection fraction and stroke volume did not change.

The two groups were comparable with regard to clinical characteristics and renal function. Urinary sodium excretion rate at baseline was not different between mild HF patients and normal subjects(98.6+6 vs 102+7mEq/24 h), respectively.

Author Conclusion:

These results show a reduced ability to excrete a sodium load and early abnormalities of cardiac and hemodynamic adaptations to salt excess in patients with mild heart failure and no signs or symptoms of congestion.

Funding Source:

University/Hospital:

First clinica Medica, Napoli University, Napoli, Italy

Reviewer Comments:

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.	HF group: 2,254 mg/d (98+6 mEq/24) Control group: 2,346 mg/d (102+7 mEq/24)
What was the target of sodium intake in the intervention and comparison groups?	Moderate sodium diet: 2,300 mg/d (100mEq/day) High sodium diet+sodium supplement: 5,750 mg/d(250mEq/d)
Was the difference in sodium status (i.e., change in urinary sodium excretion) measured between groups? If so, please specify.	HF group: 5,060 mg/d (220mEq/d) Control group: 5,290 mg/d (225mEq/d) *Estimated from the article (fig.3)
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.	No

Population target was untreated patients with no signs or symptoms of congestion, relatively preserved hemodynamic function, hormonal profile, and sodium excretory properties, therefore these results may be restricted to patients with early mild HF.
Small sample size
UNa was not corrected with creatinine

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?	Yes
	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?	Yes
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.)	N/A
	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?	N/A
	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?	Yes
	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?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
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?	???
	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?	Yes
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)?	No
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	No
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	No
9.	Are conclusions supported by results with biases and limitations taken into consideration?		No
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	No
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