HEPATOLOGY, June 1998, p. 1730-1735, Vol. 27, No. 6

Original Articles

Role of Alcohol in the Progression of Liver Disease Caused By Hepatitis C Virus Infection

George Ostapowicz¹, Katrina J. R. Watson¹, Stephen A. Locarnini², and Paul V. Desmond¹

From the ¹ Department of Gastroenterology, St. Vincent’s Hospital and ²Victorian Infectious Diseases Reference Laboratory, Melbourne, Victoria, Australia.

ABSTRACT

In patients with chronic hepatitis C, alcohol consumption has been proposed as a risk factor for the progression of liver disease; however, evidence for this remains conflicting. Two hundred thirty-four anti-hepatitis C virus (HCV)-positive patients who had a liver biopsy performed within the past 24 months were studied. Demographic data and information on risk factors were recorded. A detailed lifetime alcohol consumption history was obtained. Viral studies included HCV viral titer and HCV genotype. Mean age (± SEM) of the group was 40.8 ± 0.7 years. One hundred sixty-six (71%) were male. A risk factor for HCV infection was found in 195 patients (86%). Genotype distribution was: 1b: 22%; 1a: 15%; 1(nonsubtypable): 15%; 3a: 34%; and 2: 7%. Fifty (21%) patients had cirrhosis. Patients with cirrhosis were older (51.6 ± 1.8 years) than those with chronic hepatitis (37.6 ± 0.6 years; P = .0001), were infected at an older age (25.9 ± 2.0 vs. 20.9 ± 0.6 years; P = .001), and had a longer duration of infection (20.5 ± 1.3 vs. 16.2 ± 0.5 years; P = .0008). Patients with cirrhosis had a greater total lifetime alcohol consumption (288,765 ± 58,115 g) than those with chronic hepatitis (189,941 ± 15,453 g; P = .018). Cirrhotic patients also had greater total alcohol consumption during the period of infection with HCV (240,962 ± 63,756 g vs. 146,510 ± 12,862 g; P = .02). On multivariate analysis, subject age and total alcohol consumption were independently associated with the presence of cirrhosis. Total lifetime alcohol consumption is a risk factor for the progression of liver disease caused by HCV. (HEPATOLOGY 1998;27:1730-1735.)

INTRODUCTION

After exposure to hepatitis C virus (HCV), over 70% of persons will fail to clear the infection and become chronic carriers. These individuals develop chronic hepatitis of varying severity.^1,2 Progression to cirrhosis has been reported in approximately 20% of infected persons.^3,4 Many questions remain unanswered regarding the natural history of HCV infection. While greater age and duration of infection are associated with more severe disease,⁵ it remains unclear which other factors may predispose to the development of cirrhosis. Some investigators have found more severe liver disease in persons infected with genotype 1b than in those infected with other genotypes.⁶ More recently, it has been suggested that genotype may be a surrogate for the duration of disease rather than an independent factor influencing disease progression.^7,8 Earlier investigators concluded that HCV viral load may predispose to more severe disease.^9,10 This has not been confirmed in more recent studies.^7,11 Greater diversity of HCV quasispecies,¹² coinfection with hepatitis B virus,¹³ and hepatic iron stores^14,15have also been examined; however, no firm conclusions can be reached.

Excessive alcohol use has also been proposed as a factor that influences the progression of HCV infection. Its significance, however, especially that of “moderate drinking,” remains unclear. While some investigators have reported excessive alcohol use to be associated with the development of more significant liver disease or cirrhosis,^16,17 these findings are not supported by the work of others.^5,18 Retrospective analysis of alcohol consumption is very difficult and time-consuming. Populations used in previous studies have often been small and not comparable. Methods employed in assessing alcohol consumption have often been inadequate and included the examination of intake over short periods of time, such as during the 12 months before diagnosis or over a period of 5 years. Other investigators classified subjects into heavy or light drinkers according to differing criteria (40-60 g/d) without indication of the period of time over which this was assessed. None of the studies have performed a detailed assessment of lifetime alcohol consumption, which is necessary to accurately examine the relationship between alcohol intake and the progression of liver disease.

The aims of this study were to: 1) examine the association between alcohol use and the severity of liver disease by performing a detailed assessment of lifetime alcohol consumption; and 2) identify other factors related to the development of cirrhosis in a large group of Australian patients with chronic HCV infection.

PATIENTS AND METHODS

Patients. Patients were recruited from those referred to liver clinics at St. Vincent’s Hospital (SVH), Melbourne, Australia. Since January 1990, approximately 1,300 patients with HCV have been assessed at SVH. Fifty percent of the referrals have been from general practitioners, while others have been from the Red Cross Blood Bank (identified through routine blood donor screening) (29%), other specialists (14%), and SVH outpatients (7%). Patients who had a liver biopsy performed between January 1992 and December 1996 were asked to participate in the study. Liver biopsies were performed on those individuals who had alanine transaminase (ALT) elevated more than 1.5 times the upper limit of normal and were being considered for interferon therapy, or those in whom significant liver disease was suspected on clinical grounds. Informed consent was obtained from each patient. This study was approved by the SVH ethics committee.

Questionnaire. Multiple demographic characteristics were recorded on each of the study patients. These included sex, age, country of birth, racial origin, and occupation (both present and past). Risk factors for HCV infection were assessed in detail. Injecting drug use (IDU) with reference to duration and frequency of use was recorded. Blood transfusion histories included dates, places, and number of transfusions received. Tattoos, needle stick injuries, and other exposure to blood (including vaccinations, surgery, dental work, acupuncture, body piercing, and any traditional therapies that included cutting the skin with nonsterile instruments), with dates of first and last exposure, were also recorded. A detailed alcohol history was taken using questions from a previously validated questionnaire.¹⁹ In subjects who had consumed more than 10 drinks of alcohol during their lives, drinking habits were assessed from when they first started, and followed through changes in their drinking patterns until their current intake. For each period, the subject was asked at what age his/her drinking behavior changed, the number of days per month that he/she drank alcohol, the average number of drinks consumed (containing the equivalent of 10 g in pure ethanol) on any day, the maximum number of drinks on any occasion, the type of beverage consumed on most occasions, and the pattern of drinking (table 1). All questionnaires were administered by one investigator (G.O.).

 

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table 1. Alcohol Questionnaire

Diagnosis of HCV Infection. All patients tested positive on at least two independent HCV antibody tests (second-generation enzyme immunoassay, Abbott Laboratories, Chicago, IL; and Monolisa, Sanofi Diagnostics Pasteur, Marnes-La-Coquette, France). Patients with indeterminate serology and those with another cause of chronic liver disease, e.g., hemochromatosis, autoimmune chronic active hepatitis, were excluded. Patients coinfected with hepatitis B virus were included in the study.

Histology. Cirrhosis was diagnosed by pathologists at SVH Anatomical Pathology Department according to recognized criteria. Standardized criteria for the quantitation of inflammation and fibrosis were used in all cases. Total Knodell²⁰ and Scheuer²¹ scores, as well as separate fibrosis scores (Scheuer), were calculated for each biopsy.

Investigations. Liver function tests (mean of at least three ALT values on separate occasions), autoantibody levels (antinuclear and smooth muscle), and hepatitis serology (hepatitis B surface antigen, hepatitis B core antibodies, hepatitis B surface antibodies) were performed at the SVH Pathology Department. HCV RNA was detected by reverse-transcriptase polymerase chain reaction (PCR) using the AMPLICOR HCV test (Roche Diagnostic Systems, Branchburg, NJ).²² HCV genotyping was performed using the INNO-LiPA HCV (Innogenetics, Zwijnaarde, Belgium) second-generation assay. This assay is based on the reverse-hybridization principle and can detect the six major genotypes and six subtypes of HCV (1a, 1b, 2a, 2b, 3a, 3b, 4, 5, 6).²³ It has been shown to be a reliable and sensitive assay.²⁴ Quantitation of HCV RNA was performed using the AMPLICOR HCV MONITOR (Roche Diagnostic Systems) PCR test. Quantitation was performed in a subgroup of patients in whom blood samples were available before the use of interferon. All samples were spun down and stored at 20°C to 70°C within 4 hours of collection, until quantitative PCR was performed. PCR and genotyping was performed at the Victorian Infectious Diseases Reference Laboratories, Fairfield Hospital.

Variables Examined. Assessment of total and average daily alcohol consumption was performed over each patient’s lifetime (from age when first started drinking) and during the period of infection with HCV. Patients were also classified into groups according to average daily alcohol intake: 1) safe (<30 g); 2) moderate (30-60 g); or 3) heavy (>60 g). Differences between cirrhotic and noncirrhotic patients were also examined in the following variables: gender, age, duration of infection (estimated from earliest exposure to a major risk factor), age at infection (age  duration of infection), route of infection (IDU vs. blood transfusion vs. sporadic, i.e., no identifiable risk factor), HCV viral load (RNA quantitation), and HCV genotype.

Statistics. Data are expressed as mean and SEM. For comparisons between groups, we used the unpaired Student’s t test or one-way ANOVA for continuous variables, and the ² analysis for categorical variables. Variables that achieved limited significance (P < .20) on univariate analysis were used in a stepwise logistic regression to assess their impact upon the presence of cirrhosis. Statistical analyses were performed using STATA (Version 5.0, STATA Corp., College Station, TX). P < .05 was considered statistically significant.

RESULTS

A total of 234 patients were studied. Mean age (± SEM) of the group was 40.8 ± 0.7 years. One hundred sixty-six (71%) patients were male, and 68 (29%) were female. A history of IDU was the most common risk factor for HCV infection (61%), and at least one risk factor was found in 86% of the group (table 2). The majority of patients were Australian-born (68%). The country of birth of other patients was: Italy (8%), Egypt (4.5%), Vietnam (4.5%), United Kingdom (4.5%), and New Zealand (2.5%).

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table 2.   Risk Factor and Gender Distribution of the Study Population and Mean Age of Different Risk Factor Groups and Whole Study Population

The study population was similar to both the total group of patients with HCV seen at SVH (n = 1,260), and the total group of HCV patients who had had a liver biopsy (n = 486), with respect to gender, mean age, risk factors, and percentage of patients with cirrhosis.

The ALT (mean of at least three tests) was abnormal in 97% of patients. Antinuclear and smooth muscle antibodies were positive in 11% and 25% of patients, respectively. Antibodies were of low titer in most patients. While 7 (3%) patients were hepatitis B surface antigen-positive, 89 (41%) had serology consistent with previous hepatitis B virus infection (anti-hepatitis B core antigen-positive).

Cirrhosis was found on liver biopsy in 50 (21%) patients. The median Knodell Score was 5 (range, 1-11), and the median Scheuer score was 5 (range, 1-10). The distribution of fibrosis scores in the total group was: score 0 (n = 15); score 1 (n = 119); score 2 (n = 35); score 3 (n = 11); and score 4 (n = 50).

Two hundred twenty-four of the 234 persons (96%) had consumed alcohol on a regular basis; however, average and total amounts varied greatly. Lifetime average daily alcohol consumption was 28 ± 2 g (mean ± SEM). Total calculated consumption was 220,479 ± 17,621 g. Average daily alcohol consumption during the period of HCV infection (n = 193) was 32 ± 3 g, while total consumption during this period was 169,222 ± 15,738 g. Patients with IDU as their major risk factor for HCV infection (n = 142) had significantly greater average daily consumption (34 ± 3 g vs. 18 ± 2 g; P = .0002) than those in the other risk factor groups.

HCV RNA was detected in 227 (97%) patients. Genotyping was able to be performed in 216 patients. Thirty-four percent (n = 74) of the population were infected with genotype 3a, 22% (n = 47) with genotype 1b, and 15% (n = 33) with genotype 1a. In another 15% (n = 32) of cases, genotype 1 could not be subtyped. Small numbers were infected with genotypes 2 (n = 15), 4 (n = 9), and 6 (n = 3). Three patients had mixed infections (genotypes 3a/1b) (Fig. 1). Seven of the 9 patients with genotype 4 were Egyptian, and all with genotype 6 were Vietnamese. Quantitation of HCV RNA was performed in a subgroup of 72 patients. This group had a gender distribution, mean age, and proportion of cirrhotic patients similar to the whole study population.

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Fig. 1.   Cirrhosis prevalence in different genotypes (n = 216). P = not significant. (), cirrhosis; (), chronic hepatitis.

Associations With Cirrhosis. There was no significant correlation between gender and the presence of cirrhosis. Patients with cirrhosis, however, were older (51.6 ± 1.8 vs. 37.6 ± 0.6 years; P = .0001), had been infected later in life (25.9 ± 2.0 vs. 20.8 ± 0.6 years; P = .001), and had a longer duration of infection (20.6 ± 1.3 vs. 16.2 ± 0.5 years; P = .0008) than those with chronic hepatitis. The analyses involving age at infection and duration of infection excluded the sporadic group (n = 33), because these variables could not be calculated.

Patients in the sporadic group were more likely to have cirrhosis (47%) than those with any risk factor for HCV infection (17%; P = .0007). These patients were significantly older than those in the IDU, tattoo, or occupational exposure groups (table 2).

HCV viral titer did not differ significantly between patients with chronic hepatitis (2.1 × 10⁵ ± 3.6 × 10 ⁴ copies/mL) and those with cirrhosis (1.9 × 10⁵ ± 5.9 × 10⁴ copies/mL).

While there was a trend for patients with HCV genotype 1b to have cirrhosis more frequently than those with genotype 1a or 3a, this difference did not reach statistical significance on univariate analysis (P = .2) (Fig. 1).

We also examined the association between the degree of fibrosis (Scheuer score) and the subject characteristics shown in table 3. Age (P = .0001) and HCV duration (P = .0002) were statistically significant.

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table 3.   Summary of Breakdown of Variables According to Fibrosis Score on Liver Biopsy

Alcohol Consumption and Cirrhosis. Patients with cirrhosis had greater total consumption of alcohol as assessed over both their lifetime (288,765 g vs. 189,941 g; P = .018) (Fig. 2) and the duration of HCV infection (240,962 g vs. 146,510 g; P = .02) (Fig. 2), compared with those with chronic hepatitis. Average daily consumption was not statistically different between both groups (Fig. 2). Likewise, patients classified as moderate or heavy drinkers (on average daily alcohol intake) were no more likely to have cirrhosis than the “safe” drinkers. Analysis of the IDU subgroup showed an even stronger association between alcohol consumption and the presence of cirrhosis. Total alcohol consumption was significantly greater in those with cirrhosis, both over their lifetime (375,208 ± 114,621 g vs. 220,493 ± 18,652 g; P = .018) and the duration of HCV infection (302,488 ± 88,475 g vs. 165,543 ± 15,543 g; P = .01). Average daily consumption in those with cirrhosis was also higher in this group (44 ± 12 g vs. 32 ± 3 g; P = .15), although the difference did not reach statistical significance.

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Fig. 2.   (A) Comparison of total alcohol consumption between subjects with cirrhosis and those with chronic hepatitis: calculated over the patient’s lifetime (left) and during the period of infection with HCV (right). (B) Comparison of average daily alcohol consumption between subjects with cirrhosis and those with chronic hepatitis: calculated over the patient’s lifetime (left) and during the period of infection with HCV (right). (), chronic hepatitis; (), cirrhosis.

Assessment of the association between alcohol intake and the fibrosis score on liver biopsy showed a trend for increasing total alcohol consumption with increased severity of fibrosis (table 3). This was not statistically significant, however. No association was found between the level of hepatic inflammation, as assessed by Knodell and Scheuer scores, and alcohol intake.

Multivariate Analysis. Subject age and lifetime total alcohol consumption achieved statistical significance in the stepwise logistic regression. The odds ratio for subject age was 3.44 per 10 years (confidence interval: 2.35-5.04; P < .001), and for alcohol it was 1.16 per 100,000 g consumed (confidence interval: 1.02-1.31; P < .05). With a cutoff of 0.50, the model had the following characteristics: sensitivity: 52%; specificity: 96%; positive predictive value: 80%; negative predictive value: 88%; and correct classification: 87%. The associated receiver operating characteristic curve is shown in Fig. 3. The area under the curve is 0.8205.

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Fig. 3.   Receiver operating characteristic curve for the stepwise logistic regression model. With a cutoff of 0.5, the model has a sensitivity of 52% and a specificity of 96%. The area under the curve is 0.8205. (A model that generates false positives at the same rate as false negatives has no diagnostic usefulness, and its graph is close to a 45% line.)

DISCUSSION

This study has found that in subjects with HCV, there are significant independent associations between total alcohol consumption and subject age, and the presence of cirrhosis. Because 20% or more of individuals with chronic hepatitis C infection progress to cirrhosis, the discovery of “risk factors” for the development of cirrhosis is crucial for a better understanding of the natural history of hepatitis C and to enable identification of target groups in whom treatment efforts must be concentrated.

Our study recruited subjects from those attending liver clinics at a tertiary referral hospital who had previously had a liver biopsy performed. This introduces two potential biases. First, patients referred to the clinic may not be representative of the general population with HCV in the community. Selection of study populations can influence the results. Two recent community-based studies of mainly asymptomatic patients reported very low morbidity with cirrhosis rates of 0%²⁵and 2.4%.²⁶ On the other hand, a study of older patients with a history of blood transfusion, recruited from a liver clinic, found a cirrhosis prevalence of 51%.²⁷These studies represent two extremes in populations chosen for evaluation. Our study may be more representative of the overall HCV population, because it includes patients referred from a number of different sources and with varying routes of transmission. Second, patients who underwent a liver biopsy may have more severe liver disease than patients who were not biopsied. While our study patients did not differ significantly in mean age, gender, and risk factor distribution from all the hepatitis C clinic patients, they did have higher ALT values than patients who were not biopsied. Nevertheless, the finding of cirrhosis in 21% of our study subjects is comparable with that found in other studies.^3,17

Total alcohol consumption as calculated over either each subject’s lifetime or during the duration of HCV infection was an independent factor associated with the presence of cirrhosis. While a dose-dependent relationship between total alcohol consumption and severity of fibrosis was not statistically significant, some of the subgroups analyzed were small. In contrast, mean daily alcohol consumption was not associated with cirrhosis in the whole study group. This is not surprising, because this calculation does not take into consideration the duration of drinking history. This finding implies that the total amount of alcohol consumed is more important in the pathogenesis of cirrhosis. Furthermore, the adjusted risk ratio of 1.16 per 100,000 g of alcohol consumed can be interpreted as reflecting a linear relationship between total alcohol consumed and the risk of cirrhosis. It is thus possible that even moderate drinking carries some risk.

While other investigators have also found an association between alcohol intake and the presence of cirrhosis, these findings have not been universal, and the relationship between alcohol and HCV in the progression of liver disease requires clarification.²⁸ A recently published study of 2,235 HCV-infected patients found daily alcohol consumption of 50 g or more to be an independent risk factor for the progression of fibrosis.¹⁷ Similar conclusions have been reached by earlier studies that examined much smaller and select population samples.^16,29-32

Conversely, a number of investigators have failed to find a relationship between excessive alcohol intake and the presence of cirrhosis^5,18 or the histological severity of liver disease.³³ Likewise, another report through the use of a hierarchical statistical model found that alcohol and HCV were additive, rather than multiplicative, in the development of cirrhosis.³⁴ Small population samples were examined in these studies.

The divergence of results in the above trials reflects both the complex relationship between alcohol consumption and the progression of liver disease in chronic HCV, and particularly the difficulties in accurately assessing alcohol intake. The use of small and different population samples makes results even more difficult to compare. The definition of alcoholism or significant alcohol intake differed in many of the studies, as did the period of time over which alcohol consumption was assessed. In the present study, we have carefully performed an assessment of lifetime alcohol consumption. This takes into account the changes in consumption that may occur over time and gives a much more accurate picture of actual alcohol consumption than relying on the examination of, for example, a 5-year period or the 12 months before diagnosis. We used questions from Skinner’s Lifetime Alcohol History¹⁹ for our assessment. This questionnaire has been extensively used and validated and is recognized as one of the best tools for assessing alcohol intake.

The finding of subject age to be an independent factor associated with the presence of cirrhosis has also been reported by other investigators.^5,16 Subject age may be a surrogate for both the age at the time of infection and the duration of infection. While in our study, both the estimated age at the time of infection and duration of infection were associated with the presence of cirrhosis on univariate analysis, this association was not seen on multivariate analysis. Other investigators have found that age at time of infection is a significant predictor of fibrosis progression¹⁷ or the presence of cirrhosis.^35,36

The lack of significant association between HCV genotype and cirrhosis is supported by similar results in a number of other recent investigations.^7,8 This study is one of the first to include a larger number of patients with genotype 3 in its assessment. While it is impossible to completely discount the influence of genotype on disease progression, any such effect is likely to be small, and earlier findings reflect at least in part a greater duration of disease and age in those patients with genotype 1b. No association was found between viral load and cirrhosis. This agrees with the findings of other investigators.^7,11

The difficulty in assessing alcohol consumption may partly explain the previously reported conflicting results on its role in the progression of liver disease caused by chronic hepatitis C infection. This study, in which alcohol consumption was assessed in great detail, found that total alcohol consumption is independently associated with the presence of cirrhosis.

FootNotes

Acknowledgement: The authors thank Dr. D. S. Bowden, Ms. R. McCaw, and Ms. D. Marinakis for technical assistance with HCV-PCR testing and genotyping, Dr. J Santamaria for advice and help with statistical analyses, and Dr. J. Slavin for assistance in assessing liver biopsies. Molecular reagents used in HCV-PCR testing and genotyping were supplied in part by the Hepatitis C Consensus Study on Management under the auspices of Roche Molecular Systems (Branchburg, NJ).

Abbreviations: HCV, hepatitis C virus; SVH, St. Vincent’s Hospital; ALT, alanine aminotransferase; IDU, injecting drug use; PCR, polymerase chain reaction.

Dr. Ostapowicz was supported by a Postgraduate Medical Research Scholarship from the Gastroenterological Society of Australia

Received September 18, 1997; accepted January 29, 1998.

Address reprint requests to: Dr. Paul Desmond, Department of Gastroenterology, St. Vincent’s Hospital, 41 Victoria Parade, Fitzroy, Victoria, 3065, Australia. Fax: 613-9288-3590.

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