www.alcoholandhealth.org1 journal club alcohol and health: current evidence september–october 2006
TRANSCRIPT
![Page 1: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/1.jpg)
www.alcoholandhealth.org 1
Journal Club
Alcohol and Health: Current EvidenceSeptember–October 2006
![Page 2: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/2.jpg)
www.alcoholandhealth.org 2
Featured Article
Comparison of the combined marker GGT-CDT and the conventional laboratory markers of alcohol
abuse in heavy drinkers, moderate drinkers and abstainers
Hietala J, et al. Alcohol Alcohol. Advance Access published on June 23, 2006; doi:10.1093/alcalc/agl050.
![Page 3: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/3.jpg)
www.alcoholandhealth.org 3
Study Objective
• To assess whether combining gamma-glutamyltransferase (GGT) and carbohydrate-deficient transferrin (CDT) (GGT-CDT) is…
• better than using single biomarkers to detect heavy drinking
![Page 4: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/4.jpg)
www.alcoholandhealth.org 4
Study Design
• Markers compared in the following 3 groups:
– 165 heavy drinkers* with alcohol dependence– 51 moderate drinkers– 35 abstainers
• 51 heavy drinkers had evidence of liver disease but not hepatitis B or C.
• 44 heavy drinkers were later assessed during supervised abstinence.
*Drank approximately 3–40 drinks per day
![Page 5: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/5.jpg)
www.alcoholandhealth.org 5
Assessing Validity of an Article About Diagnostic
Tests
• Are the results valid?
• What are the results?
• Will the results help me in caring for my patients?
![Page 6: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/6.jpg)
www.alcoholandhealth.org 6
Are the Results Valid?
• Was there an independent, blind comparison with a reference standard?
• Did the patient sample include an appropriate spectrum of patients to whom the diagnostic test will be applied in clinical practice?
• Did the results of the test being evaluated influence the decision to perform the reference standard?
• Were the methods for performing the test described in sufficient detail to permit replication?
![Page 7: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/7.jpg)
www.alcoholandhealth.org 7
Was there an independent, blind comparison with a reference
standard?• Reference standard for heavy drinking:
– Alcohol consumption in heavy drinkers was determined by detailed interview using a Timeline Follow-back technique (a validated method).
– Consumption in moderate drinkers was determined by an unspecified questionnaire.
• Blinding:
– Blinding is not specified.
![Page 8: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/8.jpg)
www.alcoholandhealth.org 8
Did the patient sample include an appropriate spectrum of patients to
whom the diagnostic test will be applied in clinical practice?
• The sample included heavy drinkers with alcohol dependence with and without liver disease, moderate drinkers, and abstainers.
• However…
– none of the subjects had hepatitis B or C, – the entire sample included only 38 women, – all heavy drinkers drank heavily frequently, and– most importantly, no heavy drinkers without
dependence were included.
![Page 9: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/9.jpg)
www.alcoholandhealth.org 9
Did the results of the test being evaluated influence the decision
to perform the reference standard?
• The sequence of events is not specified.
• Both the evaluated test and reference standard were administered to all subjects included in this report.
![Page 10: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/10.jpg)
www.alcoholandhealth.org 10
Were the methods for performing the test described in sufficient detail to permit
replication?
• Yes.
![Page 11: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/11.jpg)
www.alcoholandhealth.org 11
What Are the Results?
• Are the likelihood ratios for the test results presented or data necessary for their calculation included?
![Page 12: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/12.jpg)
www.alcoholandhealth.org 12
Are the likelihood ratios for the test results presented or data necessary for their calculation
included?• Yes:
– The sensitivity of GGT-CDT for detecting heavy drinking was 90% (specificity 98%) and exceeded that of the other biomarkers:
• 63% for CDT alone • 58% for GGT alone • 50% for alanine aminotransferase • 47% for aspartate aminotransferase • 45% for mean corpuscular volume
![Page 13: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/13.jpg)
www.alcoholandhealth.org 13
Likelihood ratios for the test results (cont.)
• A positive GGT-CDT test had a likelihood ratio (LR) of 45 for heavy drinking.
• A negative GGT-CDT test had an LR of 0.1 for heavy drinking.
• The superior performance of GGT-CDT was not affected by the presence of liver disease.
![Page 14: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/14.jpg)
www.alcoholandhealth.org 14
Will the Results Help Me in Caring for my Patients?
• Will the reproducibility of the test result and its interpretation be satisfactory in my setting?
• Are the results applicable to my patients?
• Will the results change my management strategy?
• Will patients be better off as a result of the test?
![Page 15: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/15.jpg)
www.alcoholandhealth.org 15
Will the reproducibility of the test result and its interpretation
be satisfactory in my clinical setting?
• The GGT and CDT can be performed as described in the paper, and a formula for their combination is specified.
• The precision and accuracy of the test in this study
were provided and could be assessed locally.
• Thus, the reproducibility and interpretation could be satisfactory in settings that follow the same procedures.
![Page 16: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/16.jpg)
www.alcoholandhealth.org 16
Are the results applicable to the patients in my practice?
• No detail regarding the practice setting is provided.
• Therefore, applicability is questionable or, at least, difficult to determine.
![Page 17: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/17.jpg)
www.alcoholandhealth.org 17
Will the results change my management strategy?
• This study does not address how these tests should be integrated into practice.
– E.g., when should they be used in addition to or in lieu of questionnaires?
• As such, this study alone is unlikely to
change management strategies, though it does suggest the combined biomarker is more accurate than single blood tests.
![Page 18: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/18.jpg)
www.alcoholandhealth.org 18
Will patients be better off as a result of the test?
• Since the study does not have management implications,…
– it is not clear whether patients will be better off.
![Page 19: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/19.jpg)
www.alcoholandhealth.org 19
Summary/Clinical Resolution
• Combining biomarkers may be more fruitful than individual serum tests for detecting heavy drinking.
• This study has a number of limitations:
– Recruitment/subject sampling and selection details are not provided, making generalizability difficult to determine.
– The spectrum of subjects was limited, threatening validity.
– Blinding was not specified, and therefore not likely done.
![Page 20: Www.alcoholandhealth.org1 Journal Club Alcohol and Health: Current Evidence September–October 2006](https://reader036.vdocument.in/reader036/viewer/2022072006/56649d145503460f949e9034/html5/thumbnails/20.jpg)
www.alcoholandhealth.org 20
Summary/Clinical Resolution (cont.)
• Limitations (cont.):
– It is unknown whether some subjects who did not get the reference standard were excluded.
• Many questions remain about using combined biomarkers in clinical settings, such as…
– when they should be used instead of or in addition to questionnaires.