Heart Failure

HF: Alcohol Intake (2007)

Citation:

Gavazzi A, De Maria R, Parolini M, Porcu M. Alcohol Abuse and Dilated Cardiomyopathy in Men, Am J Cardiol. 2000; 85: 1,114-1,118.

 
Study Design:
Prospective Cohort Study
Class:
B - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
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
    1. Absence of significant coronary artery disease (over 50% luminal diameter reduction of a major coronary artery branch) at coronary angiography
    2. Absence of specific heart muscle disease or active myocarditis at endomyocardial biopsy
    3. Reduced left ventricular ejection fraction (under 50%) at contrast left ventricular angiography, radionuclide angiography or echocardiography.
  • Variable Two: Death was classified as
    1. Due to progressive heart failure
    2. Sudden and unexpected
    3. 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
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? ???