HESI: Congestive Heart Failure Population (2014)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

To evaluate the effects of a normal-Na diet (120mmol) compared with a low-Na diet (80mmol) in combination with high-dose furosemide and severe fluid restriction (1,000ml per day) in patients compensated after recently decompensated CHF, on re-admissions for worsening CHF.  

Inclusion Criteria:

Compensated patients who were hospitalized within the previous 30 days for recently decompensated CHF with following characteristics:

  • Uncompensated CHF
  • NYHA functional class IV unresponsive (decrease in urine volume, constant increase in BW, impaired symptoms of CHF) to treatment with high doses of oral furosemide up to 250mg to 500mg per day and combinations of diuretics, ACE inhibitors, digitalis, β-blockers and nitrates and to be under this therapy for at least two weeks before hospitalization
  • Patients had to have L-ventricular EF less than 35%, Creatinine less than 2mg per dL, BUN 60mg per dL or less, decreased urinary volume (less than 500ml per 24 hours), low natriuresis (less than 60mmol per 24 hours).    
Exclusion Criteria:
  • Cerebral vascular disease
  • Dementia
  • Cancer
  • Uncompensated diabetes
  • Severe hepatic disease
  • Requiring pacemaker implantation
  • Alcoholic habits
  • Declining to take part in protocol
  • Unable to follow assigned treatment
  • Did not follow treatment protocol or attend scheduled clinical visits
  • Did not adhere to fluid intake of 1,000ml per day or had reduction or discontinuation of prescribed treatments
  • Experiencing side-effects of ACE inhibitor treatment.
Description of Study Protocol:

Recruitment

Patients admitted consecutively to hospital with worsening CHF.

Design

Randomized trial with 180-day follow-up period.

Blinding Used

Physicians blinded to protocol judged patients to be compensated and therefore eligible for randomization into protocol. Physicians blinded to the study protocol performed evaluations to verify clinical status and if worsening CHF was present (main outcome).

Intervention

In addition to fluid intake of 1,000ml per day (both groups): 

  • Group1: Normal Na diet (120mmol Na per day) and continued with oral furosemide (250mg to 500mg, bid)
  • Group 2: Low Na diet (80mmol Na per day) and continued with oral furosemide (250mg to 500mg, bid).

Statistical Analysis

Intention-to-treat analysis, according to absolute risk reduction. Event distribution was calculated with Kaplan-Meir method and compared by log-rank analysis. Data was analyzed by two-tailed Student's T-test and ANOVA for repeated measures with Bonferroni post-hoc test. P<0.05 indicated statistical significance.  

Data Collection Summary:

Timing of Measurements

After hospital discharge, patients were controlled with clinical and lab evaluations as outpatients every week for the first 30 days, and those at 30-day post-discharge who met eligibility criteria were included in the study. After randomization (at 30-day post-discharge) and baseline clinical and lab assessments, patients were evaluated weekly for the first month, then q. two weeks for the next two months, and then monthly for the rest of the study.  

Dependent Variables

  • Doses of diuretics, ACE inhibitors, digitalis, antialdosterone, β-blockers and nitrates
  • Physical exam: Signs and symptoms of CHF, measurements of BW
  • BP and HR
  • Serum Na, K, Cl, bicarbonate, albumin, uric acid, creatinine, urea, glucose
  • Plasma aldosterone, BNP, PRA
  • Chest X-ray, ECG, echocardiogram to obtain EF.

Independent Variables

Normal (120mmol Na per day) vs. low-Na diet (80mmol per day).

Control Variables

 Fluid restriction (1,000ml per day), oral furosemide treatment (250mg to 500mg, bid).

Description of Actual Data Sample:
  • Initial N: 232 (88 female, 144 male) randomized (N=114 low-Na and 118 normal-Na)
  • Attrition (final N): At 180 days, N=99 low-Na and  112 normal-Na
  • Age: 72.6±8 years
  • Location: Palermo, Italy.
Summary of Results:

Key Findings

The normal-Na group had a significant reduction (P<0.05) in re-admissions. BNP values were lower in the normal-Na group compared with the low Na group (685± 255pg per ml compared with 425±125pg per ml respectively; P<0.0001). Significant (P<0.0001) increases in aldosterone and PRA were observed in the low-Na group during follow-up, whereas the normal-Na group had a small significant reduction (P=0.039) in aldosterone levels and no significant difference in PRA.

After 180 days of follow-up, aldosterone levels and PRA were significantly (P<0.0001) higher in the low-Na group. The normal-Na group had a lower incidence of re-hospitalization during follow-up and a significant decrease in plasma BNP and aldosterone levels, and PRA. 

 

Variables Low-Na Group Normal-Na Group Statistical Significance Between Treatment Groups
HR (bpm)      
Baseline 85±14 84±11 P<0.001
180 days 82±12 72±8  
Significance within Tx group NS P<0.001  
BW (kg)      
Baseline 76.9±15 75.2±14 P<0.001
180 days 80.2±13 75.3±10  
Significance within Tx group P<0.001 NS  
Diuresis (ml per 24 hours)      
Baseline 2,560±425 2,495±635 P<0.001
180 days 1,525±565 2,150±480  
Serum Na (mol per L)      
Baseline 138.3±5 138.7±7 P<0.001
180 days 132.1±5 139.5±6  
Significance within Tx group P<0.001 P<0.001  
Natriuresis (mol per 24 hours)      
Baseline 102±11 105±14 P<0.001
180 days 76±7 103±11  
Significance within Tx group P<0.01 NS  
BUN (mg per dL)      
Baseline 56.5±3.6 58.5±7 P<0.001
180 days 105±5.8 68.4±7.2  
Serum creatinine      
Baseline 1.55±0.05 1.56±0.2  
180 days 2.1±0.5 1.45±0.4  
Significance within Tx group P<0.001 P<0.01  
SBP (mm Hg)      
Baseline 126±15 125±15 NS
180 days 107±13 111±11  
Significance within Tx group P<0.001  P<0.01   
DBP (mm Hg)      
Baseline 82±13 83±14 NS
180 days 77±9 5±11  
Significance within Tx group P<0.001 P<0.001  
EF (percent)      
Baseline 29.3±5 29.5±4 NS
180 days 30.2±6 32.5±5  
Significance within Tx group NS P<0.001  

 


 

Author Conclusion:

The results of the present study show that along with a fluid restriction (1000ml per day) a normal-sodium diet improves outcome, and sodium depletion has detrimental renal and neurohormonal effects with worse clinical outcome in compensated CHF patients. Further studies are required to determine if this is due to a high dose of diuretic or the low-sodium diet.

 
Funding Source:
Other: not described
Reviewer Comments:
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? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  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")? Yes
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? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? Yes
5. Was blinding used to prevent introduction of bias? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? Yes
  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.) Yes
  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? Yes
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? 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? 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)? Yes
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? Yes
  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? Yes
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? No
  10.1. Were sources of funding and investigators' affiliations described? ???
  10.2. Was the study free from apparent conflict of interest? ???