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Heart Failure

HF: Folate and B-12 (2007)

Citation:

Witte K, Nikitin NP, et al. The effect of micronutrient supplementation on quality-of-life and left ventricular function in elderly patients with chronic heart failure. Eur Heart J. 2005; 26: 2,238-2,244.

 
Study Design:
Randomized Controlled Trial
Class:
A - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To assess the influence that long-term multiple micronutrient supplementations has on left ventricular (LV) function, levels of proinflammatory cytokines and quality-of-life (QOL) in elderly patients with chronic heart failure (HF)

Inclusion Criteria:
  • Stable HF due to ischemic heart disease confirmed by presence of a history and electrocardiographic evidence of previous myocardial infarction or important coronary artery disease in at least two vessels on selective coronary angiography. 
  • Chronic HF was defined as the presence of symptoms of fatigue or breathlessness on exertion and a LV ejection fraction (LVEF) on echocardiography of 35% or less with no other cause of breathlessness. Stability was defined as a diagnosis of at least three months in duration with no exacerbation or change in medication. 
  • On optimal therapy.
Exclusion Criteria:
  • Neurological or inflammatory conditions or other significant chronic morbidity affecting QOL or requiring long-term systemic steroid or non-steroidal anti-inflammatory drug therapy (except low-dose aspirin). 
  • Persistent atrial fibrillaton.
Description of Study Protocol:
  • Recruitment: Community-based HF unit
  • Design: Randomized double-blind
  • Blinding used: A pharmacy, with which the investigators had no contact, coordinated the identical opaque capsules of either placebo or micronutrients. The LV function was performed anonymously.
  • Intervention: Micronutrient supplementation vs. placebo.

Statistical Analysis

  • A predicted average improvement of 10% in LVEF gave a sample size to confidently (90% power) detect a significant difference between populations of 30 patients (15 in each arm)
  • Two-sided testing was used throughout the analysis without adjusting the data
    • Student's T-test was used to look at differences between the two groups for continuous variables and for the changes in variables between the two time points
    • NYHA status was examined using the x2 test
    • The results of the QOL questionnaire were treated as continuous data after confirming normality of distribution using the Kolmogorow-Smirnov test
    • Results are presented as means (SD)
    • A P-value of <0.05 was considered significant and absolute P-values have been included for important but non-significant variables.
Data Collection Summary:

Timing of measurements: Baseline and at study end (average of 295 days), except the QOL questionnaire, which was completed additionally each month.

Dependent Variables

  • Variable One: LV volumes, mass and EF were measured using ECG-gated breath hold gradient cine CMR within five days before enrollment and at study end. The analysis of anonymous and updated paired images was performed at the end of the study using MASS MRI software. 
  • Variable Two: The QOL questionnaire incorporates evaluation of NYHA class and assesses a broad range of health-related and QOL issues relevant to HF and has been used in several large HF surveys.
    • It includes 40 questions related to symptoms of fatigue, breathlessness, ankle swelling appetite, sleep, depression, mobility and social activities
    • A maximum score of 40 suggests an optimal QOL, while a score of zero suggests a very poor QOL
    • The scores were converted to a percentage of maximum at each time point
    • The results at study end were compared to the baseline
    • The monthly scores were used to look at longitudinal changes in QOL in those randomized to vitamins and  those to placebo. 
  • Commercially available ELISA kits were used for assay of immune markers in venous samples
    • TNF-a, and IL-6 were analyzed because of their clear relationship to adverse prognosis in HF and the availability of reliable detection kits
    • Concentrations of TNF-a, TNFR-1 and TNFR-2 were determined by test kits, the lower limit of detection being 0.18pg, 25pg and 2.0pg per mL, respectively
    • Plasma concentrations of IL-6 were measured by Immulite, the lower limit of detection being 1.0pg per mL. 
  • Standard protocol for six-minute walk
  • Blood samples for full blood count, renal, thyroid and liver function, N-terminal BNP and cytokine measurements (tumor necrosis factor-a (TNF-a) and soluble TNF receptor (sTNF-R). 

Independent Variables

Four capsules of micronutrients providing a daily dose of:

  • 250mg calcium
  • 150mg magnesium
  • 15mg zinc
  • 1.2mg copper
  • 50mcg selenium
  • 800mcg vitamin A
  • 200mg thiamine
  • 2mg riboflavin
  • 200mg vitamin B6
  • 5mg folate
  • 200mcg vitamin B12
  • 500mg vitamin C
  • 400mg vitamin E
  • 10mcg vitamin D
  • 150mg co-enzyme Q10.

 

Control Variables

Placebo.

Description of Actual Data Sample:
  • Initial N: 32 (gender unknown)
  • Attrition (final N): 28; two were unable to tolerate the CMR scan and two died during follow-up. One in the placebo group died of pneumonia and the other in intervention died as a result of extensive deep vein thrombosis and subsequent chest infection.
  • Age: 75.4 (SD, 4.2)
  • Ethnicity: Not described.

Other Relevant Demographics

  • Anthropometrics: Both groups were similar in age, height, weight, EF, loop diuretic dose, NYHA status, TNF-a and TNF-R levels and functional capacity 
  • Location: Berlin, Germany.
Summary of Results:

 

Variables

Treatment Group Baseline
(Measures and Standard Deviation)

Treatment Group Study End

Control Group Baseline
(Measures and  Standard Deviation)

Control Group Study End

Statistical Significance of Group Difference

LVESV (ml)

 169 (83)

138 (86)

164 (87)

172 (81)

0.02

LVEDV (ml)

 222 (86)

193 (90)

212 (95) 

224 (91)

0.03

LV Mass Diastole (g)

 160 (38)

158 (43)

143 (34) 

154 (41)

 0.08

LV Mass Systole (g) 174 (39) 167 (41) 158 (33) 166 (45) 0.08
SV (ml) 52.8 (18.1) 55.3 (20.1) 47.8 (11.8) 52.4(13.5) 0.17
LVEF (%) 25.6 (6.9) 30.9 (7.1) 26.6 (6.8) 26.2 (7.2) 0.03
Heart Rate (BPM) 62 (28) 52 (29) 67 (25) 66 (16) 0.12
Serum Mg (mmol/L) 0.9 (0.1) 1.1 (0.1) 0.9 (0.1) 0.5 (0.1) 0.04
Serum B12 (mmol/L) 392 (192) 409 (194) 420 (171) 409 (162) 0.02
Serum Ferritin (mcg/L) 103 (108) 576 (261) 93 (87) 77 (68) 0.009
Serum Folate (mcg/L) 372 (147) 400 (20) 375 (155) 285 (124) 0.008
TNF-a (pg/ml)  5.6 (3.2)  5.7 (4.5) 5.1 (2.0)   5.1 (2.1)  0.86
sTNF-RI (pg/ml) 1,228 (432) 1,207 (443) 1,161 (363) 1,450 (374) 0.16
sTNF-RII (pg/ml) 1,951 (618) 2,250 (643) 1,993 (694) 2,504 (716) 0.31
QOL 64.4 (13.4) 73.9 (1.6) 67.2 (9.8) 66.1 (11.1) 0.02

Other Findings

  • The micronutrient capsules were well tolerated and there were no adverse events
  • There was no change in baseline renal, liver or thyroid function
  • The average dose of loop diuretic in the patients taking active capsules tended to decline during follow-up [63.5 (34) vs. 56 (31) mg], while in the placebo group there wasn't any change [65 (23) vs. 67 (28) mg; P=0.09]
  • Baseline six-minute walk distance and change during follow-up were similar in the two groups 
  • There was no change in NYHA class in either group 
  • The difference in QOL scores started to diverge after six months
  • Further analysis of the data suggested that the difference in overall score was driven predominantly by the improvements in scores for exertional breathlessness, quality of sleep, daytime concentration and overall QOL ratings.
Author Conclusion:

When added to conventional therapy with beta blockers and ACE-Is, multiple micronutrient supplementations may improve LV function and patient well-being. 

Funding Source:
University/Hospital: Castle Hill Hospital
Reviewer Comments:

Confounded by the fact that multiple nutrients were in the multi-vitamin supplement.

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")? 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? Yes
  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? 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? 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? Yes
  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? 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)? 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? Yes
  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? ???
  10.1. Were sources of funding and investigators' affiliations described? No
  10.2. Was the study free from apparent conflict of interest? ???