HF: Alcohol Intake (2007)
Citation:
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To compare clinical characteristics and long-term outcome between patients with systolic dysfunction, due to alcohol abuse or to an unknown cause in a large series of men prospectively enrolled in a multi-center registry and treated with ACE inhibitors.
Inclusion Criteria:
Idiopathic dilated cardiomyopathy (IDC).
Exclusion Criteria:
- Systemic hypertension
- Cor pulmonale
- Left ventricular heart disease
- Sytemic diseases
- Patients with end-stage disease, who were on the heart transplant waiting list.
Description of Study Protocol:
- Recruitment: Enrollees of a multi-center registry (Italian Multi-Center Cardiomyopathy Study Group-SPIC)
- Design: Prospective cohort.
Statistical Analysis
- Continuous data are expressed as mean±SD
- Student's T-test for unpaired data or the chi-square test was used to assess significant differences between groups
- Paired Student's T-test was used to compare changes at follow-up vs. baseline with groups
- One-way analysis of variance with post-hoc Scheffe's test was used to detect differences among the three groups, according to categorization of alcohol abuse
- Product limit survival was calculated with Kaplan-Meier curves and differences were assessed by the Cox-Mantel test
- SPSS software was used with a P-value below 0.05 being used for significance.
Data Collection Summary:
- Timing of measurements: Baseline and the last follow-up available or at the patient's death or transplantation.
Dependent Variables
- Variable One: IDC was confirmed in every patient at baseline by demonstrating
- Absence of significant coronary artery disease (over 50% luminal diameter reduction of a major coronary artery branch) at coronary angiography
- Absence of specific heart muscle disease or active myocarditis at endomyocardial biopsy
- Reduced left ventricular ejection fraction (under 50%) at contrast left ventricular angiography, radionuclide angiography or echocardiography.
- Variable Two: Death was classified as
- Due to progressive heart failure
- Sudden and unexpected
- Occurring within one hour of new symptoms or during sleep in patients in NYHA Class I to III.
- For follow-up evaluation, left ventricular ejection fraction was serially analyzed by two-dimensional echocardiography from the apical four-chamber view, by the single-plane area-length method. Intra- and interobserver variability was 3±4% and 7±3%, respectively.
Independent Variables
- Alcohol consumption was expressed in grams per day and the average total lifetime alcohol intake in kilograms per kg of body weight
- Alcohol abusers had a daily consumption of ethanol either over 80g in the five years before enrollment or over 100g in the two years before enrollment
- They were classified as having stopped (AAS) or continued (AAC) alcohol abuse after entry into the study.
Description of Actual Data Sample:
- Initial N: 449 (338 males and 113 females)
- Attrition (final N): 338 (all males)
- Age: 44±12 for IDC and 45±10 for abusers
- Ethnicity: Not described.
Anthropometrics
- There were significantly fewer non-smokers among the alcohol abusers (P=0.00001)
- Heavy smoking was more frequent among the alcohol abusers (P=0.0001)
- Both groups were similar for NYHA class, presentation of HF, cardiac abnormalities (except ventricular tachycardia) and medications, except for ACE inhibitors (91% IDC vs. 81% abusers; P=0.03) and beta-blockers (34% IDC vs. 9% abusers; P=0.0001).
Location
Bergamo, Italy.
Summary of Results:
Other Findings
- During a mean follow-up of 59±35 months, 102 patients died and 45 underwent transplantation. Death was sudden in 50, due to progressive heart failure in 33, unspecific mechanism in nine and was non-cardiac in 10. Mechanisms of death were not different according to alcohol abuse.
- Seven-year transplant-free survival was significantly lower in alcohol abusers (41%) than in patents with IDC (53%, P=0.026) and in alcohol abuse-continued patients (27%) than in either IDC (53%) or alchol abuse-stopped patients (45%). When patients were stratified by baseline treatment, similar differences according to alcohol intake were observed.
- At the last available echocardiographic follow-up assessment (36±24 months), the patient with IDC had beneficial changes in left ventricular function vs. baseline (P<0.001). Among the alcohol abusers, only the alcohol abuse-stopped group subjects had significant improvement in LVEF vs. baseline (P=0.001). The difference remained when the patients were stratified by ACE inhibitor use or non-use of beta-blockers. When alcohol abuse continued, there was no difference in LVEF vs. baseline.
Author Conclusion:
- No significant difference was evident at baseline between the two groups. However, seven-year transplant-free survival was better in patients who abstainded and similar in IDC patients.
- Moreover, in alcohol abuse-stopped, but not in alcohol abuse-continued subjects, LVEF at follow-up increased significantly (similar to patients with IDC), suggesting potential reversibility of ventricular dysfunction, even in established disease.
Funding Source:
Government: | IRCCS Policlinico San Matteo (Spain) |
University/Hospital: | Istitutodi Fisiologia Clinica CNR, Ospedale San Michelle |
Reviewer Comments:
Quality Criteria Checklist: Primary Research
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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? | Yes | |
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? | No | |
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? | No | |
5.1. | In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? | No | |
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.) | No | |
5.3. | In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? | No | |
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? | N/A | |
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? | 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? | Yes | |
7.4. | Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? | ??? | |
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)? | 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? | 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? | ??? | |