HTN: Alcohol (2015)
Citation:
Baros AM, Wright TM, Latham PK, Miller PM, Anton RF. Alcohol consumption, %CDT, GGT and blood pressure change during alcohol treatment. Alcohol and Alcoholism, 2008; 43 (2): 192-197.
PubMed ID: 18039674
Study Design:
Before-After Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:

Research Purpose:
To examine the changes in blood pressure of alcohol dependent individuals over time in relation to alcohol drinking status as well as biological markers of alcohol consumption.
Inclusion Criteria:
- Alcohol-dependent patients participating in a randomized clinical trial of treatment therapies (Anton et al, 2005)
- Dependent on alcohol but not other substances (except nicotine)
- Absence of major psychiatric illness
- Medically stable
- Liver enzymes ALT and AST less than 2.5 times the upper limit of normal.
Exclusion Criteria:
- Major psychiatric illness
- Other substance dependence (except nicotine)
- Medically unstable
- Liver enzymes ALT and AST 2.5 or more times the upper limit of normal.
Description of Study Protocol:
Recruitment
Subjects utilized were those recruited for the Anton et al, 2005, study of therapy treatment for alcohol dependency. Subjects were randomized into two treatment therapies for that study.
Design
- A prospective cohort of only the subjects with hypertension participating in a randomized trial
- Subjects were evaluated for alcohol use at baseline and at the end of Weeks Two, Six and 12
- Blood pressure (BP), blood for liver function tests (ALT and AST), biomarkers of alcohol consumption (%CDT and GGT) and self-reported alcohol consumption measures were obtained at each visit.
Blinding Used
Implied with measurements.
Intervention
Study subjects were participants in a 12-week alcohol relapse prevention study.
Statistical Analysis
- All baseline variables were examined for predictive validity of pre-study systolic blood pressure (SBP) and diastolic blood pressure (DBP) by linear regression analysis
- During the trial, the impact of drinking status on BP at Week 12 and the relationship of biomarkers (%CDT and GGT) to BP were analyzed by ANCOVA, with study entry BP as a covariate
- Spearman's Rho (non-parametric analysis) was used to determine the relationship between percentage change in BP, GGT and %CDT over the course of 12 weeks
- All analysis were conducted using the statistical package for social sciences (SPSS).
Data Collection Summary:
Timing of Measurements
Measurements taken at baseline, two, six and 12 weeks.
Dependent Variables
- Blood pressure taken by the same electronic BP monitoring device (DINAMAP ProCare 120) that was calibrated every six months for accuracy. BP was taken while seated.
- Percentage CDT was measured by micro-column separation and ELISA assay method using test kits from Biorad Inc.; inter- and intra-assay coefficients of variation were below 10%
- GGT was measured using Abbot Aeroset auto-analyzer with inter- and intra-coefficient variations below 5%.
Independent Variables
- Alcohol consumption was measured by a calendar based self-reporting procedure, using the timeline follow-back method for the specified time (seven to 90 days)
- Mnemonics such as holidays and special dates were used
- Standardized glass examples and volumes were used to quantify daily consumption.
Control Variables
All subjects were enrolled in an outpatient alcohol treatment program, ensuring a recent, significant alcohol intake history at baseline.Description of Actual Data Sample:
- Initial N: 160 participants in the randomized trial (gender not reported); 120 participants had hypertension
- Attrition (final N): 120 participants had hypertension (93 male, 27 female)
- Age: 44±9 years of age
- Ethnicity: 86.7% white, 13.3% non-white (not described).
Other Relevant Demographics
57% were married.Anthropometrics
- 15±7 alcohol dependence scale
- 12±6 drinks per drinking day past 90 days
- 74±23% days heavy drinking past 90 days
- 873±549 standard drink units past 90 days
- 26±4 kg/m2 Body Mass Index (BMI)
- 53% nicotine use.
Location
Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC.
Summary of Results:
Key Findings
Predictive validity of baseline characteristics (significant findings)
- DBP
- Gender was a predictor of DBP at baseline (P=0.02)
- BMI was correlated with DBP (R=0.24, P=0.009).
- SBP
- Age increased with increasing SBP (P=0.03)
- BMI was correlated with SBP (R=0.28, P=0.002).
Total abstinence decreased SBP by 10mmHg (P=0.003) and SBP by 7.0mmHg (P=0.001).
Overall BP and biological markers of alcohol consumption over time (zero, six and 12 weeks)
- BP and both biological markers of alcohol consumption demonstrated a significant reduction over time (P<0.001)
- Reduction in percentage CDT and GGT were most pronounced between Weeks Zero and Six (P<0.001).
- Participants with negative (normal) percentage CDT or GGT had lower BP than those with higher percentage CDT or GGT
- Significant difference between positive and negative percentage CDT (df1, F=6.73, P=0.01) on SBP
- Significant difference between positive and negative percentage CDT (df1, F=9.35, P=0.03) and GGT (df1, F=4.62, P=0.03) on DBP.
- Change in percentage CDT and change in SBP (P=0.003; Rho, 28) and DBP (P<0.0001; Rho, 34)
- Change in GGT and change in SBP (P>0.05; Rho, 0.09) and DBP (P=0.03; Rho, 0.20).
Author Conclusion:
- This study shows that a reduction in alcohol in heavy drinkers is associated with a reduction in measured blood pressure and biological markers of alcohol consumption over the course of the 12-week study
- Participants who kept total abstinence to alcohol had significant reduction in both systolic and diastolic blood pressure over those who had any drinking. These results support the recommendation that alcohol-dependent individuals could reduce blood pressure with abstinence.
Funding Source:
Government: | Grant from National Institute on Alcohol Abuse and Alcoholism |
Reviewer Comments:
- Intent-to-treat analysis (N=160) was conducted and no difference in demographic and baseline characteristics existed
- 17 of 120 participants reported using anti-hypertensives by the end of the study, although the changes in demographics, BP and biomarkers was not statistically significant.
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? | No | |
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? | ??? | |
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? | N/A | |
3.3. | Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) | N/A | |
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? | N/A | |
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? | 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? | N/A | |
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? | Yes | |
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? | Yes | |
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? | 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)? | 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? | Yes | |
10.1. | Were sources of funding and investigators' affiliations described? | Yes | |
10.2. | Was the study free from apparent conflict of interest? | Yes | |