EAL

HF: CoEnzyme Q10 (2007)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To determine the benefit of coenzyme Q₁₀ in the treatment of congestive heart failure.

Inclusion Criteria:

In sinus rhythm and suffering from ischemic heart disease or dilated cardiomyopathy.

Left ventricular ejection fraction (LVEF) <45% and left ventricular internal diameter in diastole (LVIDD) >60 mm by echocardiography.

NYHA class 2 or 3.

Stable heart disease as determined by values of LVIDD and LVEF on 2 echocardiographic examinations spaced 3 months apart that differed by <5% and no change in medication during that time frame as well.

Exclusion Criteria:

None specified beyond the inclusion criteria.

Description of Study Protocol:

Recruitment

Not described

Design

RCT

Blinding used (if applicable)

Double blinding not described further

Intervention (if applicable)

Capsules of 100 mg coenzyme Q₁₀ in soya oil or placebo-capsules containing only soya oil were administered twice daily.

Statistical Analysis

The data were evaluated using the Wilcoxon test for unpaired data when comparing continuous/ordered data between groups, the chi-square test when comparing dichotomous data and the paired t-test when comparing changes between baseline and follow-up. A significance level of 0.05 was chosen, but for parameters derived from more than two measured parameters 0.005 was used.

Data Collection Summary:

Timing of Measurements

At baseline and after 12 weeks of intervention

Dependent Variables

Variable 1: Right atrial pressure, right ventricular systolic and end diastolic pressure, pulmonary artery pressure (PAP) at rest and after three minutes of work, pulmonary capillary wedge pressure (PCWP) at rest and after 1 and 3 minutes were measured during right heart catherization via the femoral vein.
Variable 2: Cardiac output (CO) was measured by thermodilution. The catheter was placed in the PCWP-position and the patient performed an exercise test (bicycle ergometer) at a workload of 30 Watt for 3 minutes after which CO was again measured. The work load continued until the measurements were completed.
Independent Variables: coenzyme Q₁₀

Control Variables

Description of Actual Data Sample:

Initial N: 22 (15 males, 7 females)

Attrition (final N):

Age:

43-75 years

Ethnicity:

Assumed to be Danish

Other relevant demographics:

16 had a history of acute myocardial infarction >6 months prior to the study, Nine had previously undergone a left heart catheterization. Medications were continued unchanged throughout the study.

Anthropometrics (e.g., were groups same or different on important measures)

They were non significant differences in age, gender, DCMP/IHD, NYHA, LVIDD, LVEF, cardiac index (CI), PCWP, PAP mean, right ventricular end diatolic pressure (RVEDP), systolic blood pressure, mean blood pressure, and medications (ACE-inhibitors, diuretics, digoxin and antiarhythmic drugs)

Location:

Denmark

Summary of Results:

Variables	Treatment Group Before Measures and confidence intervals	Treatment Group After Measures and confidence intervals	Statistical Significance of Group Difference	Control group Before Measures and confidence intervals	Control group After Measures and confidence intervals	Statistical Significance of Group Difference
LVEF	26 ± 8	26 ± 11	NS	32 ± 9	35 ± 8	NS
NYHA	3A	2B	NS	2B	2B	NS
BP mean rest	93 ± 11	91 ± 13	NS	90 ± 7	94 ± 9	NS
BP mean work	118 ± 15	113 ± 13	NS	109±7	112±9	NS
HR rest	75 ± 9	71 ± 11	NS	65 ± 10	66 ± 11	NS
HR work	109 ± 12	104 ± 12	NS	97 ± 14	94 ± 15	NS
Right Atrial Pressure (mm Hg)	6 ± 3	5± 2	NS	7 ± 4	7 ± 3	NS
Right ventricular end diastolic pressure (mm Hg)	8 ± 3	8 ± 4	NS	10 ± 4	10 ± 4	NS
Pulmonary artery pressure mean rest (mm Hg)	27 ± 10	21 ± 7	p = 0.02	24 ± 8	25 ± 11	NS
Pulmonary artery pressure mean work (mm Hg)	55 ± 18	50 ± 17	ns	49 ± 13	49 ± 14	NS
Pulmonary capillary wedge pressure mean rest (mm Hg)	17 ± 10	13 ± 8	ns	16 ± 8	16 ± 9	NS
Pulmonary capillary wedge pressure mean rest/1 min work (mm Hg)	40 ± 16	32 ± 15	p = <0.02	32 ± 13	31 ± 11	NS
Pulmonary capillary wedge pressure mean rest/3 min work (mm Hg)	42 ± 18	36 ± 14	ns	38 ± 14	37 ± 11	NS
Cardiac Output rest (l/min)	4.2 ± 0.7	4.6 ± 0.8	ns	4.9 ± 1	5 ± 1.3	NS
Cardiac Output work (l/min)	6.1 ± 0.9	6.5 ± 1.3	ns	7.4 ± 2	7.4 ± 2.4	NS
Stroke Index rest (ml/stroke/m²)	31.28 ± 3.43	36.2 ± 2.72	p = <0.005	39.94 ± 6.68	40.36 ± 10.56	NS
Stroke Index work(ml/stroke/m²)	31.47 ± 4.40	34.66 ± 5.09	p = < 0.05	40.35 ± 10.28	41.51 ± 12.89	NS

Other Findings

There was no mention of side effects or adverse events in the paper.

Author Conclusion:

Treatment with coenzyme Q₁₀ 200 mg per day resulted in a significant decrease in pulmonary artery pressure at rest, pulmonary capillary wedge pressure at work and stroke index at rest and work indicating improvemnt in left ventricular function in patients suffereing fro congestive hear failure caused by ischemic heart disease or dilated cardiomyopathy in NYHA class 2 to 3.

Funding Source:

University/Hospital:

Aalborg Hospital (Denmark)

Reviewer Comments:

Small number of subjects.

Randomization not described

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?		No
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	No
	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%.)	N/A
	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?		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?		No
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	No
	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?	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?	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?	N/A
	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?	N/A
	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?		No
	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?		No
	10.1.	Were sources of funding and investigators' affiliations described?	No
	10.2.	Was the study free from apparent conflict of interest?	???