Carbohydrate-deficient transferrin as a marker of alcohol intake: a study with healthy subjects

Asialo-transferrin: Biochemical aspects and association with alcohol abuse investigation

Asialo-human transferrin (asialo-hTf) is a glycoform of the human serum protein transferrin characterized by the lack of the sialic acid (SA) terminal unit. It is known that glycosylation micro-heterogeneity and the presence of SA are strongly involved in protein functioning and pathophysiological activities. Some hTf glycoforms are valuable biomarkers for the detection of both genetic defects of glycosylation and/or sialoform distribution changes. The detection of the carbohydrate deficient transferrin (CDT) glycoforms is currently a widely employed method for the diagnosis of chronic alcohol abuse. The physiological significance of asialo-hTf is still unclear, despite its important biological implications. The current knowledge suggests that asialo-hTf may be involved in regulation of iron transport and release at the hepatic level, which, consequently, could strongly be affected by alcohol consumption. For these reasons, a deeper understanding of asialo-hTf structure and its physiological role is required, and an improved method of its analysis would favor the detection of both chronic abuse and other habits of alcohol intake and/or misuse. Thus, suitable analytical methods possessing higher sensitivity and specificity in comparison with the currently available techniques are certainly recommended. The present review summarizes the studies on asialo-hTf structure, roles, and detection techniques mainly in relation to its possible use as a potentially additional useful biomarker of alcohol abuse, and underlines its prospective value as a forensic and diagnostic tool.

Biomolecules and Biomarkers Used in Diagnosis of Alcohol Drinking and in Monitoring Therapeutic Interventions

BACKGROUND

The quantitative, measurable detection of drinking is important for the successful treatment of alcohol misuse in transplantation of patients with alcohol disorders, people living with human immunodeficiency virus that need to adhere to medication, and special occupational hazard offenders, many of whom continually deny drinking. Their initial misconduct usually leads to medical problems associated with drinking, impulsive social behavior, and drunk driving. The accurate identification of alcohol consumption via biochemical tests contributes significantly to the monitoring of drinking behavior.

METHODS

A systematic review of the current methods used to measure biomarkers of alcohol consumption was conducted using PubMed and Google Scholar databases (2010-2015). The names of the tests have been identified. The methods and publications that correlate between the social instruments and the biochemical tests were further investigated. There is a clear need for assays standardization to ensure the use of these biochemical tests as routine biomarkers.

FINDINGS

Alcohol ingestion can be measured using a breath test. Because alcohol is rapidly eliminated from the circulation, the time for detection by this analysis is in the range of hours. Alcohol consumption can alternatively be detected by direct measurement of ethanol concentration in blood or urine. Several markers have been proposed to extend the interval and sensitivities of detection, including ethyl glucuronide and ethyl sulfate in urine, phosphatidylethanol in blood, and ethyl glucuronide and fatty acid ethyl esters in hair, among others. Moreover, there is a need to correlate the indirect biomarker carbohydrate deficient transferrin, which reflects longer lasting consumption of higher amounts of alcohol, with serum γ-glutamyl transpeptidase, another long term indirect biomarker that is routinely used and standardized in laboratory medicine.

Comparison of ethyl glucuronide and carbohydrate-deficient transferrin in different body fluids for post-mortem identification of alcohol use

AIMS

Alcohol abuse is a major risk factor for premature death. Confirming the role of alcohol consumption in cause-of-death investigations has, however, remained difficult, due to lack of reliable biomarkers.

METHODS

We compared ethyl glucuronide (EtG) and carbohydrate-deficient transferrin (CDT) assays from serum, urine, cerebrospinal fluid and vitreous humor in a forensic autopsy population with either a positive (n = 38) or negative (n = 22) history of alcohol abuse based on detailed medical and police records and forensic toxicological investigations.

RESULTS

A positive blood alcohol concentration (median 1.15‰, range 0-3.3‰) was found in 26/38 (68%) of the cases with a documented history of alcohol abuse. EtG concentrations (mean ± SD) in urine (339 ± 389 mg/l, P < 0.001), vitreous humor (4.2 ± 4.8 mg/l, P < 0.001), serum (6.9 ± 8.9 mg/l, P < 0.01) and cerebrospinal fluid (1.7 ± 2.7 mg/l, P < 0.01) were significantly higher among the cases with a positive history of alcohol use than those in the alcohol-history negative group, whereas in corresponding comparisons CDT was significantly different only in cerebrospinal fluid (4.3 ± 2.1 vs. 2.3 ± 0.6%, P < 0.05). The highest sensitivities (92%) in detecting ante-mortem alcohol use were obtained for urine and vitreous humor EtG assays.

CONCLUSION

Our data indicate that measurements of EtG in urine or vitreous humor show the highest diagnostic accuracies in post-mortem investigations of excessive alcohol consumption and can be recommended for routine applications.

Analysis of carbohydrate deficient transferrin serum levels during abstinence

An alcohol-associated change in the serum transferrin glycoform pattern, carbohydrate-deficient transferrin (CDT), is used as a biomarker of chronic moderate to heavy alcohol consumption. Furthermore, CDT is employed as a marker of abstinence. Here, we analyzed CDT in patients with chronic excessive alcohol abuse at the beginning and during abstinence. Twenty-nine alcohol dependent patients were recruited from an in-patient abstention program. Reported drinking levels were at least 100 g/d (range up to 450 g/d; mean: 248.9±94.7 g/d) within the last month before study entry. Blood samples were drawn at the beginning and during the abstention program and the relative concentration (%CDT) of CDT was determined using ion exchange followed by immunodetermination of CDT. At study entry, 25/29 patients had a %CDT level above the established cutoff. Although CDT levels declined during abstinence in most patients, in ten patients with %CDT levels just above the cutoff at the start of the program, the CDT values remained elevated 6 weeks after cessation of drinking. Our data indicate that %CDT levels below the cutoff cannot even rule out long lasting excessive alcohol abuse. Further, measurement of %CDT should be interpreted with special care when used as a marker of alcohol abstinence.

The carbohydrate-deficient transferrin test in hospital practice

We report an experience in two hospital populations of the use of a commercially available kit for the detection of carbohydrate-deficient transferrin (CDT). Patients from a drug and alcohol unit and a gastroenterology clinic at two hospitals were selected for the study. Sera were used from blood samples collected for routine biochemical assays. All patients had a specific alcohol history taken by one clinician and CDT results were correlated with reported alcohol intake by the patient and where relevant by their relatives. Sensitivity and specificity of the CDT assay were calculated using an alcohol intake of 60 g/day as the cut-off point for detection of heavy drinking. The CDT assay had a specificity of 95%; a sensitivity of 80% and a 90% positive and 89% negative predictive value. The severity and type of liver disease had little influence on the CDT result and a high alcohol intake was the only predictor of a raised CDT concentration. The assay provided information not available from routine investigations in some patients and also proved useful in monitoring patients over periods of up to 4 years. The test has a role in the evaluation of patients in a hospital practice where routine histories of alcohol intake may lack sensitivity and where other diseases may cause routine liver tests to be unreliable.

Factors Affecting %CDT Status at Entry Into a Multisite Clinical Treatment Trial: Experience from the COMBINE Study

BACKGROUND

Carbohydrate-deficient transferrin (CDT) occurs as a higher percentage of normal transferrin (%CDT) in heavy drinkers. %CDT is used as a marker of both alcohol use disorder severity and treatment outcome both clinically and in treatment trials. Nevertheless, little is known about the parameters that predict which patients are %CDT positives at treatment entry. These parameters might include level of drinking, days of abstinence before testing, and severity of alcohol dependence before evaluation.

METHODS

%CDT levels were collected before randomization from participants of the COMBINE Study, a large federally sponsored multisite clinical trial evaluating medications and behavioral therapies in alcohol-dependent outpatients. %CDT (assayed in a central laboratory) was available in 1,193 individuals for whom drinking history in the 30 days before testing and measures of alcoholism severity were documented. The effects of drinking history and alcohol severity were evaluated for prediction of a %CDT-positive test status.

RESULTS

Less percent days abstinent (PDA) and more drinks per drinking day (DDD) were predictive of higher rates of %CDT-positive patients (maximum 67%). Up to 14 days of continuous abstinence before testing did not appear to significantly affect %CDT status. Rates of %CDT positives remained reasonably steady up to about 40% PDA. Years of drinking at dependence levels had an unexpected negative impact on %CDT-positive rates while previous treatment had a small but positive impact of %CDT-positive rates. ADS and DrInC scores had no predictive value over and above recent drinking amounts on %CDT status.

CONCLUSIONS

%CDT is more likely to be positive in those who have more days of drinking and to a lesser degree in those who drink more per drinking day. It can remain positive even in those alcoholic subjects who stop drinking many days before testing. Alcoholic subjects with more treatment experiences appear to have a marginally higher %CDT-positive rate.

Biomarkers in alcoholism

Alcoholism ranks as one of the main current threats to the health and safety of people in most Western countries. Therefore, a high priority should be given to aims at reducing its prevalence through more effective diagnosis and early intervention. The need for objective methods for revealing alcohol abuse in its early phase has also been widely acknowledged. It is postulated here that the diagnosis of alcohol use disorders could be markedly improved by a more systematic use of specific questionnaires and laboratory tests, including blood ethanol, serum gamma-glutamyltransferase (GGT), carbohydrate-deficient transferrin (CDT), and mean corpuscular volume of erythrocytes (MCV). Recent research has provided new insights into the relationships between ethanol intake, biomarkers, and factors affecting their diagnostic validation, including gender, age, and the effects of moderate drinking and obesity. It appears that the concept of reference intervals for several ethanol-sensitive parameters in laboratory medicine needs to be revisited. CDT is currently the most specific marker of alcohol abuse, and when combined with GGT using a mathematically formulated equation a high sensitivity is reached without loss of assay specificity. Possible new biomarkers include minor ethanol metabolites (protein-acetaldehyde condensates and associated autoimmune responses, ethylglucuronide, and phosphatidylethanolamine), 5-hydroxytryptophol, and genetic markers although so far their routine applications have been limited.

Exclusion of trisialo-transferrin from carbohydrate-deficient transferrin measurement: advantage in patients with chronic liver disease?

BACKGROUND

Biological markers for chronic alcohol consumption like MCV or gammaGT or carbohydrate deficient transferrin (CDT) are useful, but far from being perfect. In patients with liver disease a reliable marker for chronic alcohol consumption as the underlying etiology is highly needed. Recently, a new ELISA based version of the carbohydrate-deficient-transferrin (CDT-TRISIALO (-)) assay has been developed, which measures asialo-, monosialo- and disialo transferrin, but excludes trisialo- transferrin; that modification suggests higher sensitivity and specificity in detecting recent alcohol consumption in patients.

AIMS

The study goal was to evaluate the sensitivity, specificity, positive and negative predicitive value of this new carbohydrate-deficient-transferrin assay (CDT-TRISIALO (-)) in a group of patients with liver disease and to compare the results with that of the established CDT assay (CDT-TRISIALO (+)).

PATIENTS AND METHODS

Our study population consisted of 110 consecutive patients (male: n = 80 [72.7 %], female: n = 30 [27.3 %]) with liver disease of the following etiologies: chronic alcohol consumption (n = 51 [46.4 %]; Out of them 30 alcohol abusing patients were assessed by cage = 1 and 21 alcohol dependent patients were assessed by cage = 2, chronic viral hepatitis (n = 33 [30.0 %]) including 25 [22.7 %] patients with chronic hepatitis C infection and 8 [7.3 %] patients with chronic hepatitis B infection), haemochromatosis (n = 4 [3.6 %]), mechanical cholestasis (n = 17 [15.5 %]) and other liver diseases (n = 5 [4.6 %] including autoimmune hepatitis (n = 2) and primary biliary cirrhosis (n = 3)). 27.3 % of our patients (n = 30) had no liver cirrhosis whereas the majority (72.7 %, n = 80) had liver cirrhosis.

RESULTS

In our population of liver disease patients the CDT-TRISIALO (-) assay had a sensitivity of 72.7 % and specificity of 58.1 % for recent alcohol consumption at the published cutoff level of 2.6 %. The positive predictive value was 34.0 % and the negative predictive value was 87.8 %. Sensitivity and specificity of the CDT-TRISIALO (+) assay at the recommended cutoff level of 4.7 % were similar, 77.3 % and 49.3 %, respectively. The positive and negative predictive values were 30.9 % and 88.1 %. CDTTRISIALO (+) and CDT-TRISIALO (-) levels increased significantly with higher Child-Pugh stages.

CONCLUSION

The newly developed carbohydrate deficient transferrin test (CDT-TRISIALO (-)) is of no advantage as compared to the established assay (CDT-TRISIALO (+)) when used in a patient population with liver disease. In that population, normal CDT-TRISIALO (-) helps to exclude recent alcohol consumption; this results from the high negative predictive value of a normal CDT-TRISIALO (-).

Correlation of liver dysfunction biological markers to the mood status of alcohol-dependent individuals

OBJECTIVE

Alcohol intake is a major cause of liver cirrhosis as well as chronic liver disease, and commonly coexists with mood disorders such as depression and anxiety. The aim of the present study was to investigate the possible correlation between liver dysfunction related to alcohol intake with anxiety and depressive-like symptomatology prior to and after the detoxification period.

METHODS

One hundred alcohol abusing/dependent subjects (81 males and 19 females) were treated on an inpatient basis according to a standard detoxification protocol and measurements of serum levels of hepatic enzymes (ASAT, ALAT, γGT), and measures of anxiety (HARS), depression (HDRS) and global functioning (GAS) were also obtained at baseline and at weekly intervals over a period of 4 weeks.

RESULTS

Increased levels of hepatic enzymes were observed upon admission that were significantly reduced (P<0.001) following completion of the detoxification treatment. In addition, the psychopathological profile was improved at the end of the detoxification period and a significant correlation was obtained between the levels of hepatic enzymes and the global functioning of alcohol-dependent individuals.

CONCLUSION

This observation further supports a relationship between the depressogenic action of alcohol and the disordered liver function observed in alcohol-dependent individuals, with possible implications in the diagnosis and treatment of mood disorders associated to alcohol abuse.

Multicenter Validation Study of the %CDT TIA Kit in Alcohol Abuse and Alcohol Dependence

BACKGROUND

Carbohydrate-deficient transferrin (CDT) and gamma-glutamyl transferase (GGT) are used as biomarkers of alcohol misuse. The aim of this study was to evaluate, in terms of sensitivity and specificity, the performance of the new Bio-Rad %CDT TIA kit and GGT assay for identifying alcohol abuse and alcohol dependence (according to the DSM-IV criteria).

METHODS

An open multicenter study (30 centers) over 3 months, including patient groups of "abusers," "dependents," and controls, was conducted in France.

RESULTS

In alcohol abuse, the sensitivity of GGT was 0.56, and that of CDT was 0.80; in alcohol dependence, the sensitivity of GGT was 0.86, and that of CDT was 0.91. The specificity of GGT was 0.77, and that of CDT was 0.83. The association of GGT with CDT increased sensitivity for alcohol abuse to 0.90 and for alcohol dependence to 0.99, but it appreciably decreased specificity (0.63).

CONCLUSIONS

%CDT is the better screening marker for alcohol abuse and dependence, but GGT is still a useful marker for the detection of alcohol dependence. As an assay method, the second-generation Bio-Rad %CDT immunoassay can be recommended for routine CDT measurement.

Carbohydrate-deficient transferrin (CDT)--a biomarker for long-term alcohol consumption

Carbohydrate-deficient transferrin (CDT) is a biomarker for chronic alcohol intake of more than 60 g ethanol/d. It has been reported to be superior to conventional markers like gamma-glutamyltransferase (GGT) and mean corpuscular volume MCV). This review covers theoretical and analytical aspects, with data from controlled drinking experiments and from different population subgroups such as subjects with different liver diseases or different drinking patterns. CDT determinations are particularly indicated in (1) cases of chronic alcohol consumption and relapses after withdrawal, (2) license reapplication after driving under alcohol influence, (3) differentiating patients with enzyme-inducing medication from those with alcohol abuse, 4) congenital disorders of glycosylation such as carbohydrate-deficient glycoprotein syndrome Ia (CDGS Ia), and (5) patients treated for galactosemia. The main advantage of CDT is its high specificity, as evidenced in combination with increased alcohol consumption. CDT values are not markedly influenced by medication except in immunosuppressed patients, who may show low CDT values. In general, CDT values appear less elevated after alcohol intake in women. The main disadvantage is the relatively low sensitivity. Hence, this parameter is not suitable for screening for subjects with alcohol abuse in the general population. As CDT, GGT, and MCV are connected with chronic alcohol consumption by different pathophysiological mechanisms, a combination of these parameters will further improve the diagnostic value.

Should we use carbohydrate deficient transferrin as a marker for alcohol abusers?

Carbohydrate deficient transferrin (CDT) is one of the conventional markers for chronic alcohol consumption, is used by researchers and clinicians. A number of enzymes are affected by ethanol intake. The induction or inhibition of sialyl transferase and plasma sialidase may be involved in the CDT level elevation. An alteration of protein transport during post-translational modification could be a primary mechanism in the impairment of protein metabolism associated with chronic alcohol abuse. Transferrin being a steroid responsive protein, sex-based hormonal variations might contribute to the lower sensitivity of CDT. Varying hormonal statuses such as pregnancy, use of contraceptives, menopause/ menstrual cycle can alter iron homeostasis in women. CDT levels are markedly affected by iron homeostasis. Several CDT assay methods appeared promising, but it is not readily apparent which technique is the most accurate. Moreover, false-positive results of CDT have been reported in non-alcohol related hepatic failure and in rare conditions. Therefore clinical interpretation of CDT needs careful assessment in patients with alcohol-related or non-alcohol-related health disorders.

Use of biomarkers for alcohol use disorders in clinical practice

BACKGROUND

Biomedical markers may provide additive objective information in screening and confirmation of acute or recent consumption, intoxication, relapse, heavy drinking, hazardous/harmful use/abuse and dependence and alcohol use related organ dysfunction (alcohol use-related disorders: AUDs).

AIMS

To review the use of biomarkers in clinical practice to detect AUDs.

FINDINGS

About one-fifth of the patients seen in clinical practice have AUDs, which offer a variety of treatment options if diagnosed. The diagnosis of AUDs relies on clinical and alcohol-related history, physical examination, questionnaires and laboratory values. No clinical available laboratory test [e.g. for acute abuse: alcohol in blood or breath; for chronic alcohol abuse: gamma-glutamyl transferase (GGT), mean corpuscular volume (MCV), carbohydrate-deficient transferrin (CDT)] is reliable enough on its own to support a diagnosis of alcohol dependence, harmful use or abuse. Sensitivities, specificities and the predictive values may vary considerably according to patient and control group characteristics (e.g. gender, age or related comorbidity). In patient groups with limited cooperation markers may be helpful when considering treatment options.

CONCLUSIONS

More research is needed to determine the value of markers (single or combined, with questionnaires) in the context of clinical decision-making algorithms in defined settings and with defined dichotomous outcome variables.

Ethyl glucuronide discloses recent covert alcohol use not detected by standard testing in forensic psychiatric inpatients

BACKGROUND

Considerable lives and money could be saved if one could detect early stages of lapsing/relapsing behavior in addicted persons (e.g., in safety-sensitive workplaces) and could disclose harmful drinking in social drinkers. Due to the serious public health problem of alcohol use and abuse worldwide, markers of alcohol use have been sought. Both ethyl glucuronide (EtG) and phosphatidyl ethanol (PEth) appear to have high sensitivity and specificity and a time frame of detection that may elucidate alcohol use not detected by standard testing. Our aim was to assess their potential for detecting recent covert alcohol use under controlled conditions.

METHODS

Thirty-five forensic psychiatric inpatients in a closed ward who had committed a substance-related offense ( section sign 64 StGB), were followed for 12 months. The complete time spectrum of possible alcohol consumption was covered by the complementary use of breath and urinary ethanol (hours), urinary EtG (days), %carbohydrate-deficient transferrin (CDT)/PEth (weeks), and gamma-glutamyltranspeptidase (GGT)/mean corpuscular volume (MCV) (weeks-months).

RESULTS

Fourteen of the 146 urine samples examined were positive for EtG. In all EtG-positive cases, patients reported alcohol consumption of between 40 and 200 g of ethanol 12-60 hr prior to testing. Urinary and breath ethanol were positive in only one case. In the blood samples, PEth was not positive in any case and %CDT did not exceed the reference value. Isoelectric focusing showed no abnormal Tf subtypes.

CONCLUSIONS

The findings emphasize the diagnostic and therapeutic usefulness, specificity, and sensitivity of EtG as a marker of recent alcohol use. Such a test is needed in numerous settings, including alcohol and drug treatment (to detect lapse/relapse), in safety-sensitive work settings where use is dangerous or in other settings where use may be inappropriate (e.g., such as driving, workplace, pregnancy, or monitoring physicians or other professionals who are in recovery and working), or for testing other groups (such as children or those with medical problems) where alcohol use would be unhealthy or unsafe. The health, social and socioeconomic benefits arising from the future use of these markers is hard to overestimate.

The activity of beta-hexosaminidase (uHex) and gamma-glutamyltransferase (uGGT) in urine as non-invasive markers of chronic alcohol abuse: II. Opiate-dependent subjects receiving methadone substitution

The usefulness of beta-hexosaminidase (uHex) and gamma-glutamyltransferase (uGGT) activity in urine as markers of chronic alcohol abuse was examined in male methadone programme participants. The group consisted of 24 non-abusing and 21 alcohol-abusing men. It has been demonstrated that the uHex test is one of the best alcohol abuse markers for opiate-dependent individuals (Receiver Operating Characteristic (ROC) area under the curve (AUC) 0.82, sensitivity 0.70, specificity 0.82). The uGGT test can be used as a marker of alcohol abuse in opiate-dependent men, however, its parameters are worse than those of uHex (ROC AUC 0.73, sensitivity 0.71, specificity 0.77). Among serum markers, only the relative amount of carbohydrate-deficient transferrin (s%CDT) has parameters sufficient for diagnostic use (ROC AUC 0.74, sensitivity 0.60, specificity 0.86). Factors other than alcohol can render the commonly used sGGT and sHex tests useless (differences between means for abusing and abstinent patients were insignificant, AUC ROC were lower than 0.7-0.65 and 0.69, respectively). Their good parameters, low costs, ease of use and non-invasive character are all features which make uHex and uGGT highly useful tools in the detection of chronic alcohol abuse in opiate-dependent patients participating in a methadone substitution programme.

Sensitivity and specificity of carbohydrate-deficient transferrin in drinking experiments and different patients

Information provided by patients about the amounts of alcohol they drink may often be too subjective and therefore unreliable. Because of the possible serious consequences of interactions between alcohol and medication, reliable laboratory test markers for alcohol consumption are needed. Carbohydrate-deficient transferrin (CDT) is at present the best available objective measure of drinking behavior. During a withdrawal trial, 92 alcohol-dependent patients who had been admitted to a hospital in an ethanol-intoxicated state were monitored over the following 28 days by using the percent carbohydrate-deficient transferrin (%CDT of total transferrin) (%CDT) method. At the time of admission, 63% showed elevated %CDT levels. After a subsequent period of abstinence, a decrease in %CDT levels was apparent in four different groups of patients, whereas in two groups, comprising the greatest number of patients, normal %CDT levels were evident after 14 days of abstinence. In patients whose CDT levels were very high at study initiation, it took at least 21 to 28 days--and sometimes longer--for CDT to decrease to the radioimmunoassay (RIA) %CDT test cutoff point of 2.5. In a further study of 56 male alcohol-dependent patients, we measured liver enzyme concentrations, mean corpuscular volume (MCV), and four CDT variants on the first day of evidence of withdrawal syndrome. We found a significant correlation between results on the Munich Alcoholism Test (MALT) and MCV levels; among gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels; and among all four CDT variants. A cluster analysis yielded three clusters: (1) GGT, AST, and ALT levels; (2) MCV levels and MALT results; and (3) all CDT measurement variants. We conclude that these three clusters measure different detriments to the patient and that all available CDT variants are commensurate.

The activity of beta-hexosaminidase (uHex) and gamma-glutamyl-transferase (uGGT) in urine as non-invasive markers of chronic alcohol abuse: I. Alcohol-dependent subjects

It has been demonstrated that in alcohol-dependent men the uHex test is one of the most powerful discriminating tools, while uGGT has a discriminating power similar to that of sHex but worse than that of uHex, sGGT and s%CDT. Receiver Operating Characteristic (ROC) areas under the curves (AUC) for uHex, uGGT, s%CDT, sHex and sGGT were 0.92, 0.79, 0.88, 0.79 and 0.92, respectively. Due to their good parameters, low cost, ease of use and non-invasive character the uHex and uGGT tests are useful tools for the detection of chronic alcohol abuse.

The European acamprosate trials: conclusions for research and therapy

In an excellent methodological approach, the European acamprosate study project showed that acamprosate increases sobriety times. In one randomized prospective study (n = 260) comparing acamprosate and placebo, with a 1-year treatment phase and 1-year follow-up phase, the authors found that acamprosate is effective only in Lesch type I and type II patients. To investigate the possible influence of diagnostic subgrouping, we applied the Lesch typology in a co-work with the main researchers of the UK study. The UK results concerning acamprosate's effects in the types do not mirror the Vienna results, but the numbers of type I and type II patients, retrospectively found as included in the UK centers, were too small for any conclusions. The distribution of the types points to the fact that too many type III and IV patients had been included to give acamprosate the chance to be effective. Following our typology and also these studies, we developed special treatment approaches. For relapse prevention studies, the cumulative abstinence duration together with the Lesch typology seems to be promising.

Carbohydrate-deficient Transferrin as a Marker of Chronic Alcohol Abuse: A Critical Review of Preanalysis, Analysis, and Interpretation

Background: Carbohydrate-deficient transferrin (CDT) is used for diagnosis of chronic alcohol abuse. Some 200–300 reports on CDT have been published in impact factor-listed journals. The aims of this review were to condense the current knowledge and to resolve remaining issues on CDT.

Approach: The literature (1976–2000) was searched using MEDLINE and Knowledge Server with “alcohol and CDT” as the search items. The data were reviewed systematically, checked for redundancy, and organized in sequence based on the steps involved in CDT analysis.

Content: The review is divided into sections based on microheterogeneity of human serum transferrin (Tf), definition of CDT, structure of human serum CDT, pathomechanisms of ethanol-induced CDT increase, preanalysis, analysis, and medical interpretation (postanalysis). Test-specific cutoff values for serum CDT and causes of false positives and negatives for chronic alcohol abuse are discussed and summarized.

Summary: Asialo- and disialo-Fe2-Tf, which lack one or two complete N-glycans, and monosialo-Fe2-Tf (structure remains unclear) are collectively referred to as CDT. Diminished mRNA concentration and glycoprotein glycosyltransferase activities involved in Tf N-glycan synthesis and increased sialidase activity most likely account for alcohol-induced increases in CDT. Knowledge about in vivo and in vitro effects on serum CDT is poor. Reliable CDT and non-CDT fractionation is needed for CDT measurement. Analysis methods with different analytical specificities and recoveries decreased the comparability of values and statistical parameters of the diagnostic efficiency of CDT. CDT is the most specific marker of chronic alcohol abuse to date. Efforts should concentrate on the pathomechanisms (in vivo), preanalysis, and standardization of CDT analysis.

Validity of carbohydrate deficient transferrin and other markers as diagnostic aids in the detection of alcohol related seizures

OBJECTIVE

The role of alcohol misuse in the genesis of seizures is probably often undetected. The aim was to investigate the utility of carbohydrate deficient transferrin (CDT) compared with other biomarkers and clinical examination in the diagnosis of alcohol related seizures.

METHODS

The study included consecutively 158 seizure patients-83 men and 75 women-with mean age 45 (16-79) years. Seizures related to alcohol use were identified by a score > or =8 in the alcohol use disorders identification test (AUDIT positive). AUDIT was applied as the gold standard to which sensitivity and specificity of the various markers were related. Blood samples were obtained from 150 patients on admission and analysed for ethanol, liver enzymes, and CDT, using AXIS Biochemicals' %CDT-TIA kit.

RESULTS

53 patients (34%) were AUDIT positive. Using the commonly applied decision value for %CDT of 5.0%, a sensitivity of 41% and a specificity of 84% were obtained. Analysis of receiver operator characteristics (ROC) curves disclosed an optimal cut off value for %CDT of 5.4%, which yielded a sensitivity of 39% and a specificity of 88%. At a specificity of 80%, the sensitivity was 43% for %CDT and 26% for GGT. The %CDT sensitivity was markedly higher for men than for women. Compared with GGT, ASAT, ALAT, and ASAT/ALAT ratio, CDT was the best single biomarker for alcohol related seizures. However, even in the subgroup of withdrawal seizures, the sensitivity level barely exceeded 50%. Clinicians scored alcohol as the main cause of the seizure in only 19 cases (12%). In 38 (24%) cases, clinicians suspected that alcohol had a role (sensitivity of 62% at a specificity of 89%). Their ability to identify AUDIT positive patients was better than that of any biomarker, but many cases were missed. Agreement of clinicians' scores to CDT was only fair (kappa=0.28). CDT concentrations were significantly increased among alcohol abstaining patients on enzyme-inducing antiepileptic drugs. Six out of 16 patients with false positive CDT results were exposed to such drugs.

CONCLUSIONS

CDT is not recommended as a stand alone marker for alcohol related seizures, but may provide a useful contribution to the overall diagnostic investigation of seizures. Confirmatory studies are needed as to the apparent vulnerability of CDT to antiepileptic drugs.

Substance abuse and emergency psychiatry

Given the high rates of comorbidity, patients commonly present with multiple diagnoses to PESs or crisis services. Clinicians must be well versed in the evaluation, differential diagnosis, and treatment of patients with substance-abuse disorders or other Axis I, II, or III conditions if they are to provide state-of-the-art treatment of patients in need of emergency care.

Carbohydrate deficient transferrin for detection of alcohol relapse after orthotopic liver transplantation for alcoholic cirrhosis

Early diagnosis and monitoring of an alcohol relapse in patients after orthotopic liver transplantation for alcoholic cirrhosis is of importance for the long-term outcome. A prospective study of 97 patients who underwent orthotopic liver transplant for alcoholic cirrhosis has been performed. All of the recipients considered for analysis survived for at least 3 months and were under the care of one specialist psychologist. Mean follow-up amounted to 48.5+/-1.4 months. The rates of alcohol relapse at 1 and 3 years after orthotopic liver transplant were 6 and 9%, respectively. Carbohydrate-deficient transferrin is a biological marker for alcohol abuse independently of liver disease and has been used for the first time ever in liver graft recipients. A total of 830 values were included prospectively in the study population. Detection of alcohol relapse had a sensitivity of 92% and a specificity of 98%. Changes in carbohydrate-deficient transferrin levels indicated clandestine and sporadic drinking after transplantation. Furthermore, clinical events were not found to influence carbohydrate-deficient transferrin, either in patients with or without alcoholic relapse. In our opinion, carbohydrate-deficient transferrin is a useful screening marker for alcohol relapse in patients after orthotopic liver transplant for alcoholic cirrhosis, to select those patients who need special attention from the psychologist.

Carbohydrate-deficient transferrin in the assessment of harmful alcohol consumption: diagnostic performance and clinical significance

The last decade saw the emergence of carbohydrate-deficient transferrin (CDT) as the most promising marker for the diagnosis of alcohol abuse. Daily alcohol consumption of four beers, four glasses of wine or three standard drinks causes increased concentrations of CDT in serum. CDT is serum transferrin with a reduced content of oligosaccharides due to the detrimental effects of alcohol metabolism on the glycosylation pathway of hepatocytes and/or the increased activity of circulating glycosidases in serum. Most current CDT procedures entail separation of normal transferrin from CDT in a charged matrix-like isoelectric focusing and ion exchange chromatography, followed by detection/quantitation of CDT by a myriad of immunoassays: immunoblotting, radioimmunoassay, enzyme immunoassay and nephelometry. New CDT procedures present the advantages of improved performance, inexpensive automation and CDT results expressed as a percentage of total serum transferrin. CDT's major asset is its high specificity in well-defined populations i.e. individuals ingesting 60 g alcohol daily for at least a week.The sensitivity rates, which vary between 22% and 81%, depend on the amount of alcohol ingested, time of sample collection after the cessation of drinking, age, gender and the cut-off point chosen for analysis of tests' results. Regarding clinical applications, best outcome is achieved when the test is used to confirm a suspicion of alcohol abuse and when monitoring abstinence and relapses.The low prevalence of alcohol abuse in the general population challenges its use as a screening test.With the advent of inexpensive automation and the constant emergence of innovative, improved tests, we are seeing the rise of a new era in alcohol abuse diagnosis as affordability and education allows widespread use of CDT in a variety of settings.

Carbohydrate-deficient transferrin and alcohol use in medical examiner cases

Carbohydrate-deficient transferrin (CDT) has been studied as an index of heavy alcohol use. The present study evaluates the utility of CDT as a marker for chronic alcohol use in medical examiner cases. Over a 5-month period, serum specimens were collected in consecutive deaths that were referred to the medical examiner's office (N = 25). Manner of death was accidental in nine cases, homicide/suicide for eight cases, and natural causes for seven cases. Fifteen of the 17 cases having alcohol abuse had positive CDT levels above threshold, indicating chronic use (sensitivity 88%). Eight cases had no evidence of alcohol abuse but three of these cases had CDT levels also above threshold (specificity 63%). There was no correlation between serum CDT levels and the time of death to blood collection for the total sample, indicating that CDT is stable postmortem for at least 36 h. CDT appears to have value as a marker of ante-mortem alcohol use prior to time of death in medical examiner cases.

Smoking, obesity, and hypertension alter the dose–response curve and test sensitivity of carbohydrate-deficient transferrin as a marker of alcohol intake

Serum carbohydrate-deficient transferrin (CDT) is a specific and comparatively sensitive marker of excessive alcohol use; however, reports of its sensitivity vary according to the population or patient groups studied and their average alcohol intake. We have characterized the dose–response curve between alcohol intake and CDT concentrations in a study of 1400 men and women from a community-based twin registry. Our results show that mean CDT increases with increasing reported alcohol consumption even within the range of alcohol use considered to be nonhazardous. We found significant effects of sex, age, smoking, previous alcohol dependence, body mass index, and diastolic hypertension on the alcohol-CDT dose–response curve. These variables either affect test sensitivity or require adjustment of reference intervals. The results also provide insight into the physiological and biochemical factors that affect CDT concentration.

Carbohydrate deficient transferrin in detecting relapse in alcohol dependence

Patients reports together with findings at clinical examination and information from an informant such as a relative were used to categorise patients as relapsed or not relapsed during a 6 month period of out-patient treatment at an alcohol problems clinic. At each fortnightly visit, blood was taken for measurement of serum gamma-glutamyl transferase and carbohydrate deficient transferrin (Pharmacia method). A total of 53 patients attended for at least one follow-up visit. Mean CDT differentiated relapsers from non-relapsers at seven of the 11 visits (P < 0.05), but at no visit did mean GGT differentiate. CDT tended to become elevated after a relapse more quickly than GGT. However, whether using upper limit of normal (ULN), or defining a 'positive test' as > last test and either > 20% above lowest previous test or > ULN, specificity (averaged over the 11 visits) was greater for GGT than CDT. Some of the false positive results for CDT were in patients who, shortly after having a positive test, relapsed, suggesting that a rising CDT can herald a relapse admitted by the patient. This could not be shown for false positive GGT results. Inspection of individual trajectories of alcohol consumption and blood test results shows that for some patients GGT is the more effective marker of relapse, whilst for others CDT operates better.

Fatty acid ethyl esters: short-term and long-term serum markers of ethanol intake

This review includes a description of short-term and long-term markers of ethanol intake and their clinical utility. The major portion of this report is a summary of studies on fatty acid ethyl ester, a new marker for monitoring both acute and chronic ethanol intake. With the markers described in the review, algorithms to assess recent ethanol intake, chronic ethanol intake, and end organ damage are included to provide a practical approach to the evaluation of the patient.