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A S Lok

Publications and source records attributed to A S Lok.

At least 19 recordsLinked to original sources
PubMed2001

Management of hepatitis C patients by primary care physicians in the USA: results of a national survey.

Hepatitis C is a major health problem worldwide, yet very little research has been performed to assess the knowledge base and practice patterns of primary care physicians (PCPs) regarding hepatitis C. The aim of this study is to determine the knowledge base and practice patterns of a nationwide cohort of PCPs. A survey was developed to assess the knowledge of PCPs regarding risk factors for hepatitis C, management of hepatitis C patients and attitude regarding testing for hepatitis C. The survey was mailed to 4000 PCPs in the USA. A total of 1412 (39%) PCPs completed the survey. The vast majority, > 90%, of PCPs correctly identified the most common risk factors for hepatitis C. However, only 59% indicated they ask all patients about hepatitis C risk factors, 70% reported they test all patients with hepatitis C risk factors and 78% test all patients with elevated liver enzymes for hepatitis C. Most (72%) PCPs would refer an HCV-positive patient with elevated aminotransferase but only 28% would refer an HCV-positive patient with normal aminotransferase to a specialist. One-fourth of the PCPs did not know what treatment to recommend for hepatitis C patients. Our data suggest that hepatitis C patients may be underdiagnosed and under-referred. Specific educational initiatives and practice guidelines for PCPs are needed to optimize the recognition of patients at risk for hepatitis C and to ensure appropriate testing and referral.

Adult↗
PubMed2001

Hepatitis B infection in patients with acute liver failure in the United States.

Occult hepatitis B virus (HBV) infection has been reported in 30% to 50% of patients with acute liver failure (ALF) in small case series. The aim of this study was to determine the prevalence of occult HBV infection in a large series of ALF patients in the United States and the prevalence of precore and core promoter variants in patients with ALF caused by hepatitis B. Sera from patients in the US ALF study and liver, when available, were tested using nested polymerase chain reaction (PCR) with primers in the HBV S and precore regions. PCR-positive samples were sequenced. Sera and/or liver from 139 patients (39 males, 100 females; mean age, 42 years) enrolled between January 1998 and December 1999 were studied. Twelve patients were diagnosed with hepatitis B, 1 with hepatitis B+C+D coinfection, and 22 had indeterminate etiology. HBV DNA was detected in the sera of 9 (6%) patients; all 9 had ALF caused by hepatitis B. HBV genotypes A, B, C, and D were present in 4, 3, 1, and 1 patients, respectively. Seven of these 9 patients had precore and/or core promoter variants. Liver from 19 patients were examined. HBV DNA was detected in the liver of 3 patients with ALF caused by hepatitis B, but in none of the remaining 16 patients with non-B ALF. Contrary to earlier reports, occult HBV infection was not present in this large series of ALF patients in the United States. HBV precore and/or core promoter variants were common among US patients with ALF caused by hepatitis B.

Acute Disease↗
PubMed2001

Liver transplantation in patients with hepatitis B virus infection: outcome in Asian versus white patients.

Previous studies have found that Asian patients transplanted for hepatitis B virus (HBV) infection had worse outcomes than white patients. The aim of this study was to compare outcomes in Asian and white patients listed for liver transplantation for HBV infection. Data of all patients with HBV infection listed for liver transplantation between January 1996 and June 1998 from 20 centers in North America were collected using a survey. Total patients enrolled were 325 (171 whites, 126 Asians, 28 other races). There was no difference in demographics, liver biochemistry, and HBV replicative status between Asians and whites at the time of listing. More Asians had hepatocellular carcinoma and fewer Asians had hepatitis C or D virus coinfection. At the time of this survey, 70 Asians (55%) and 99 whites (58%) had been transplanted. Actuarial 2-year survival posttransplantation for Asians (88%) and whites (92%) was similar. Recurrent HBV infection occurred in 8 (11%) Asians and 12 (12%) whites. Five patients with recurrent HBV infection died, 4 of whom were Asian. Actuarial 2-year survival for Asians versus whites with recurrent HBV infection was 60% versus 90% (P =.04). In this large cohort of patients, overall survival and recurrent HBV infection posttransplantation were comparable between Asians and whites. However, Asians with recurrent HBV infection posttransplantation had significantly higher mortality.

Antiviral Agents↗
PubMed2001

Chronic hepatitis B.

Explore the source record for details and available documents.

Hepatitis B, Chronic↗
PubMed2001

Outcome of liver transplantation for hepatitis B: report of a single center's experience.

Results of liver transplantation (LT) for hepatitis B have improved significantly with the use of hepatitis B immune globulin (HBIG) and/or lamivudine. The aim of this study is to review the long-term outcome of patients who underwent LT for hepatitis B. Records of 41 patients who underwent LT for hepatitis B and survived 3 months or longer post-LT were reviewed. Twenty patients were administered no immunoprophylaxis or short-term intramuscular HBIG, whereas 21 patients were administered high-dose intravenous (IV) HBIG. Median post-LT follow-up in these 2 groups was 76 months (range, 4 to 155 months) and 25 months (range, 4 to 68 months), respectively. Hepatitis B recurred in 15 (75%) and 4 patients (19%) who underwent LT in the pre-HBIG and post-HBIG eras, respectively. Cumulative rates of recurrent hepatitis B at 1 and 3 years post-LT in these 2 groups were 66% and 77% and 20% and 20%, respectively (P <.001). Recurrent hepatitis B in the post-HBIG era correlated with antibody to hepatitis B surface antigen titer less than 100 IU/L. Nine patients with recurrent hepatitis B were administered lamivudine for 13 to 49 months (median, 28 months); 6 patients continued to have stable or improved liver disease, whereas 3 patients developed virological breakthrough with slow deterioration of liver disease. Long-term IV HBIG is effective in preventing recurrent hepatitis B. The risk for recurrent hepatitis B is negligible after the first year post-LT. Among patients with no virological breakthrough, lamivudine can stabilize or improve liver disease for up to 4 years in patients with recurrent hepatitis B post-LT.

Adult↗
PubMed2001

Comorbid illness is an important determinant of health-related quality of life in patients with chronic hepatitis C.

OBJECTIVES: Chronic hepatitis C (CHC) patients selected for entry into treatment trials have been reported to have impaired health-related quality of life (HRQOL). However, these trials have an inherent selection bias, and HRQOL in CHC patients may have been underestimated because of the exclusion of patients with comorbid illness. The aim of this study was to assess HRQOL in an unselected group of CHC patients and to identify factors associated with impairment in HRQOL. METHODS: A total of 220 consecutive eligible CHC patients were enrolled from a hepatology clinic. HRQOL was assessed by the short form 36 (SF-36) and comorbid illnesses were assessed by an interview. RESULTS: CHC patients had significantly lower SF-36 scores in all subscales and in the summary scales when compared to those of the healthy general population in the United States (p < 0.001). Compared to CHC patients entering treatment trials, our patients had lower SF-36 scores on five subscales (p < 0.001). The presence of comorbid illness was the most important predictor of HRQOL in CHC patients. However, CHC alone resulted in significantly lower SF-36 scores in all subscales and summary scales (p < or = 0.003) compared to those of the healthy U.S. population. There was no correlation between SF-36 scores and history of i.v. drug use or dependence. alcohol dependence. and serum aminotransferase levels. CONCLUSIONS: We conclude that unselected CHC patients presenting for medical evaluation have a reduced HRQOL, which is lower than that reported for CHC patients entering treatment trials. CHC alone is associated with significant impairment in HRQOL, but the presence of comorbid illness leads to further diminution in HRQOL.

Adult↗
PubMed2000

Hepatitis B e antigen-negative chronic hepatitis B in Hong Kong.

Hepatitis B e antigen-negative chronic hepatitis B (e-CHB) has been reported in Asia but its prevalence and clinical significance have not been determined. The aims of this study were to determine the prevalence of e-CHB in Hong Kong and the frequency of precore and core promoter mutations in these patients. A cross-sectional study was performed in 350 consecutive Chinese patients (230 men and 120 women; mean age +/-SD, 42 +/- 13 years) with chronic hepatitis B virus infection. A total of 243 (69%) patients were hepatitis B e antigen (HBeAg)-negative of whom 15% had clinical cirrhosis. In the remaining 85% of patients, 63% had normal and 22% had elevated transaminases. Serum hepatitis B virus (HBV) DNA was detectable using branched DNA assay in 46% of HBeAg-negative patients with clinical cirrhosis/elevated transaminases. Forty-five percent of the patients with e-CHB had the precore stop codon mutation, and an additional 41% had core promoter changes. There was no correlation between the presence of precore/core promoter mutations and liver disease or HBV-DNA levels. Overall, 17% of HBeAg-negative patients were viremic and had evidence of chronic liver disease (e-CHB) with mean HBV-DNA levels comparable with that in HBeAg-positive patients. In summary, we found that e-CHB may be present in up to 17% of HBeAg-negative patients seen in a tertiary referral center in Hong Kong. e-CHB may be a heterogeneous condition and is not invariably associated with the precore HBV mutant. Population studies are needed to determine the true prevalence of e-CHB in Asia and to assess its natural course and response to treatment.

Adolescent↗
PubMed2000

Hepatitis B infection: pathogenesis and management.

Although hepatitis B is an ancient disease, most of the advances in our knowledge of its epidemiology, prevention, pathogenesis, natural history and treatment were made in the last 30 years. The prospect of global eradication of HBV infection within the next 50 years is technologically possible but implementation of worldwide vaccination against hepatitis B will require significantly more time to overcome the social and economic hurdles. While there is reasonable optimism that HBV infection will be eradicated, there are currently 300 million HBV carriers worldwide who are at risk of dying from liver failure or hepatocellular carcinoma, and there will continue to be new cases of HBV infection for many more years. Thus, HBV infection cannot be considered to be a health problem of the past. The focus of hepatitis B research at the turn of the millenium will be the development of more effective therapies that can be applied to all patients with chronic HBV infection. These treatments need to be effective in inhibiting HBV DNA synthesis and in eliminating ccc DNA. They may involve monotherapy with more potent antiviral agents that do not induce resistance, but are more likely to require a combination of antiviral agents or antiviral and immunomodulatory agents. These treatments must be safe, convenient to administer, and affordable. It is likely that new therapies with increasing efficacy will be available in the next one to two decades and combination therapy will be used widely by 2010. These treatments will induce sustained remission in the majority of patients who can afford them but provision of treatment to all those who need them will be more difficult. Other areas of hepatitis B that need to be addressed are the prevalence of occult HBV infection, the changing epidemiology and clinical significance of HBV variants, in particular the A1896 mutant, and the mechanisms of immune clearance and pathogenesis.

Antibody Formation↗
PubMed2000

Evolution of hepatitis B virus polymerase gene mutations in hepatitis B e antigen-negative patients receiving lamivudine therapy.

Lamivudine has been shown to be effective in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B, but its long-term efficacy and the rate of resistant mutations in patients with HBeAg-negative chronic hepatitis B is less clear. Twenty-nine patients with HBeAg-negative chronic hepatitis B, who have received lamivudine for at least 1 year were studied to determine the antiviral response, the rate and pattern of lamivudine-resistant mutations, and the effect of lamivudine-resistant mutations on HBeAg status. The mean duration of treatment was 21 +/- 7 months. Before treatment, core promoter variant was detected in 16 (55%) patients and precore stop codon variant in 18 (62%) patients. Serum hepatitis B virus (HBV) DNA was detected by solution hybridization assay in 62%, 4%, and 24% and by polymerase chain reaction (PCR) assay in 100%, 31%, and 40% at months 0, 6, and 24, respectively. The cumulative rates of detection of lamivudine-resistant mutations after 1 and 2 years of treatment were 10% and 56%, respectively. In addition to the duration of treatment, core promoter mutation was associated with the selection of lamivudine-resistant mutants. Three patients with lamivudine-resistant mutations had reversion of the precore stop codon mutation; in 2 patients this was accompanied by the reappearance of HBeAg. We found that lamivudine-resistant mutants were detected at similar rates in patients with HBeAg-negative as in patients with HBeAg-positive chronic hepatitis B. Additional changes in other parts of the HBV genome may restore the replication fitness of lamivudine-resistant mutants.

Adult↗
PubMed2000

Posttransplantation: future therapies.

Recent advances in prophylaxis and treatment of hepatitis B virus (HBV) infection after liver transplantation have improved the outcome of liver transplantation for hepatitis B. Currently, the long-term use of hepatitis B immune globulin (HBIG) and/or nucleoside analogues are the only effective therapies to prevent or ameliorate HBV recurrence in liver transplant patients. However, they are very expensive, and breakthrough infections due to resistant HBV mutants are not infrequent. New strategies are being sought to decrease the risks of breakthrough infection and to increase the cost-effectiveness of liver transplantation for hepatitis B. Vaccination to prevent de novo infection is strongly recommended before transplantation, despite a decreased response in this immunosuppressed population. Adoptive transfer of immunity with such therapies as bone marrow or cytotoxic T lymphocyte transplants or xenotransplantation of an organ from a donor, which is not susceptible to infection by HBV may be effective in preventing or treating recurrent HBV posttransplantation. In addition, gene therapies and use of nucleoside and nucleotide analogues to disrupt various stages of the HBV life cycle may prevent or slow viral replication or assembly of the virus. Ultimately, the most effective therapy for the prevention of recurrent hepatitis B after liver transplantation will involve a combination of HBIG with one or more of the new antiviral agents.

Antiviral Agents↗
PubMed1999

Different hepatitis B virus genotypes are associated with different mutations in the core promoter and precore regions during hepatitis B e antigen seroconversion.

Mutations in the core promoter and precore regions are frequently found in hepatitis B e antigen (HBeAg)-negative patients, but precore stop codon mutation is restricted to hepatitis B virus (HBV) genotypes that have T at nucleotide 1858. The aims of this study were to determine the role of core promoter and/or precore mutations in HBeAg seroconversion and their impact on the subsequent course of liver disease, and to determine if core promoter mutations are more frequently selected in patients with HBV genotypes that preclude the development of precore stop codon mutation. Serial sera from 45 patients with chronic HBV infection were polymerase chain reaction (PCR)-amplified, and the HBV core promoter and precore regions were sequenced. Ninety-two percent of patients had core promoter or precore mutations after HBeAg seroconversion: 42% had core promoter changes only, 38% had precore stop codon mutations only, and 12% had changes in both regions. Seventy-three percent of the patients had persistently normal aminotransferases, and only 8% had multiple flares in aminotransferases after HBeAg seroconversion. Core promoter changes were significantly more common in patients infected with HBV who have C at nucleotide 1858 (91% vs. 27%; P <.01), while precore stop codon changes were exclusively found in patients infected with HBV who have T at nucleotide 1858 (87% vs. 0; P <.01). The vast majority of our patients had core promoter and/or precore mutations after HBeAg seroconversion. Nevertheless, most patients had sustained remission of liver disease. Our data suggest that core promoter changes are preferentially selected in patients infected with HBV genotypes that preclude the development of precore stop codon mutation.

Adolescent↗
PubMed1999

Current practice patterns of primary care physicians in the management of patients with hepatitis C.

Approximately 4 million Americans are infected with the hepatitis C virus (HCV). Most patients with hepatitis C have no symptoms until cirrhosis is established. Thus, initial diagnosis and management of hepatitis C rely on primary care physicians identifying and screening high-risk individuals. We administered a survey to 1,233 primary care physicians in a health maintenance organization (HMO) in April 1997 to assess their knowledge of the risk factors for HCV infection and approach to the management of 2 hypothetical HCV antibody-positive patients, 1 with elevated and the other with normal alanine transaminase (ALT). Four hundred four (33%) physicians returned the survey. Ninety percent of respondents correctly identified the risk factors for HCV infection, but 20% still considered blood transfusion in 1994 as a significant risk factor for HCV infection. Sixty-two percent of respondents would refer HCV antibody-positive patients with abnormal transaminase levels, but 33% would follow these patients themselves, even though none of the respondents had treated any hepatitis C patient on their own. Forty-three percent of respondents overestimated, while 29% did not know the efficacy of interferon treatment. Sixty-five percent of respondents would retest patients for HCV antibody, regardless of risk factors and transaminase levels. We found that most primary care physicians correctly identified the significant risk factors for HCV infection and appropriately managed the 2 hypothetical patients, but there was considerable confusion about the use of HCV tests and the effectiveness of treatment. Educational programs for primary care physicians are needed to implement hepatitis C screening and to initiate further evaluation and management of those who test positive.

Hepatitis C↗