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Dive into the research topics where Kevin T. Chaung is active.

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Featured researches published by Kevin T. Chaung.


Journal of Clinical Gastroenterology | 2012

High frequency of recurrent viremia after hepatitis B e antigen seroconversion and consolidation therapy.

Kevin T. Chaung; Nghiem B. Ha; Huy N. Trinh; Ruel T. Garcia; Huy A. Nguyen; Khanh K. Nguyen; Gabriel Garcia; Aijaz Ahmed; Emmet B. Keeffe; Mindie H. Nguyen

Background: The primary treatment endpoint for hepatitis B e antigen (HBeAg)-positive chronic hepatitis B is HBeAg seroconversion; however, data on the durability of response are inconsistent. Goals: Our goal was to investigate the rate of recurrent viremia after HBeAg seroconversion and subsequent discontinuation of therapy. Methods: We retrospectively studied 88 consecutive Asian American patients who achieved HBeAg seroconversion [loss of HBeAg and development of antibody to HBeAg (anti-HBe)] among 458 HBeAg-positive patients who received oral antiviral therapy at 3 US clinics between March 1998 and November 2010. Recurrent viremia was defined as reappearance of detectable serum hepatitis B virus DNA (>100 IU/mL) on 2 consecutive laboratory tests from previously undetectable levels. Results: Antiviral medications used at the time of HBeAg seroconversion included: lamivudine (23%), adefovir (34%), entecavir (36%), tenofovir (4%), and combination therapy (3%). Antiviral therapy was continued after HBeAg seroconversion in 49 patients (group I) and discontinued in the other 39 patients after consolidation therapy [median=12 months (range, 1 to 55 mo)] (group II). No patients in group I experienced recurrent viremia, whereas 90% in group II did. Elevated alanine aminotransferase also occurred in 38% of group II patients [median peak alanine aminotransferase 249 IU/mL (range, 93 to 1070 IU/mL)]. Conclusions: Despite consolidation therapy, almost all patients who discontinued therapy after achieving HBeAg seroconversion and complete viral suppression experienced recurrent viremia, and close to half also experienced biochemical flares. HBeAg seroconversion does not seem to be a durable treatment endpoint for many patients, and they should be monitored carefully for virologic relapse and biochemical flares if antiviral therapy is withdrawn.


Alimentary Pharmacology & Therapeutics | 2016

Reduction of chronic hepatitis B-related hepatocellular carcinoma with anti-viral therapy, including low risk patients

Derek Lin; Hwai I. Yang; Nghia Nguyen; Joseph Hoang; Yoona Kim; Vinh Vu; A. Le; Kevin T. Chaung; Vincent G. Nguyen; Huy N. Trinh; Jiayi Li; Jianqi Zhang; Ann W. Hsing; Chien-Jen Chen; Mindie H. Nguyen

Anti‐viral therapy in chronic hepatitis B (CHB) is associated with a reduced risk of hepatocellular carcinoma (HCC) primary described in patients with cirrhosis.


Journal of Clinical Gastroenterology | 2013

High proportion of hepatitis C virus in community Asian American patients with non-liver-related complaints.

Kevin C. Kin; Brian Lin; Nghiem B. Ha; Kevin T. Chaung; Huy N. Trinh; Ruel T. Garcia; Khanh K. Nguyen; Huy A. Nguyen; Eduardo B. da Silveira; Brian S. Levitt; Mindie H. Nguyen

Goals and Background: Besides United States population born between 1945 and 1965, screening for hepatitis C virus (HCV) is not recommended for the general US population. However, HCV may be more prevalent in certain subgroups and screening may be warranted. The goal of this study was to examine the proportion of HCV in a large sample of community Asian American patients presenting for non–liver-related complaints. Study: We conducted a cross-sectional study of 1246 patients tested for hepatitis C virus antibodies (anti-HCV) referred to 2 gastroenterology clinics for non–liver-related gastrointestinal reasons between January 2001 and February 2011. We determined HCV status and patient history via electronic medical record review. Results: Of the 1246 study patients tested for anti-HCV, the majority were Asian (81.4%) and 29 Asian patients (2.9%) had positive anti-HCV. HCV proportion in the remaining 232 non-Asians (non-Hispanic whites and Hispanics) was 1.7%. Asians with positive anti-HCV were more likely to have had blood transfusions (31.0% vs. 6.6%, P<0.0001) or acupuncture (10.3% vs. 1.5%, P<0.0001). Of the 976 Asian patients with hepatitis B surface antigen testing, 38 (3.9%) also had detectable hepatitis B surface antigen. Conclusions: Among patients seen at community gastroenterology clinics for non–liver-related reasons, HCV proportion was 1.7% for non-Asians and 2.9% for Asians. Screening for HCV should be offered to high-risk patients presenting to gastroenterology clinics with unrelated gastrointestinal complaints.


Journal of Clinical Gastroenterology | 2015

Renal Function in Chronic Hepatitis B Patients Treated With Tenofovir Disoproxil Fumarate or Entecavir Monotherapy: A Matched Case-Cohort Study.

Nghiem B. Ha; Kevin C. Ku; Kevin T. Chaung; Huy N. Trinh; Mindie H. Nguyen

Background and Aims: Tenofovir (TDF)-associated renal dysfunction has been described in various studies of human immunodeficiency virus–infected patients. Our goal is to examine the incidence and magnitude of decrease in renal function in chronic hepatitis B patients treated with TDF. Methods: We performed a case-cohort study of 103 patients on TDF 300 mg and 103 patients unexposed to TDF (Entecavir) at 4 centers, who were matched for age±10 years, sex, and baseline estimated glomerular filtration rate (eGFR) group. Calculation and evaluation of eGFR were performed with both the Cockcroft-Gault formula and the Modification of Diet in Renal Disease formula. Results: The exposed and unexposed populations were well matched with a similar mean age (44±10 y), proportion of male patients (63.1%), and baseline eGFR groups (86.4% unimpaired). There was no significant difference in the proportion of patients reclassified to a more severe renal classification (RMSRC) or in the proportion of patients with decrease in eGFR of ≥20% in those exposed to TDF versus control. The incidence density for RMSRC was 7.4 cases per 100 patient-years in the exposed group compared with 11.5 cases per 100 patient-years in the unexposed group (95% CI, 0.31-1.34). The relative risk of exposed to unexposed was 0.64 (95% CI, 0.31-1.34). On Cox proportional hazard analysis following adjustment for sex, age, baseline diagnosis hypertension, diabetes, impaired baseline renal function, and cirrhosis, TDF was not a predictor for RMSRC or decrease in eGFR≥20%. Conclusions: TDF treatment was not an independent predictor for significant deterioration of renal function. Renal function of chronic hepatitis B patients on antiviral therapy should be monitored, especially in those who are older and/or with mildly impaired renal function.


Medicine | 2016

Lower liver cancer risk with antiviral therapy in chronic hepatitis B patients with normal to minimally elevated ALT and no cirrhosis

Joseph Hoang; Hwai I. Yang; A. Le; Nghia Nguyen; Derek Lin; Vinh Vu; Kevin T. Chaung; Vincent G. Nguyen; Huy N. Trinh; Jiayi Li; Jian Q. Zhang; Chien-Jen Chen; Mindie H. Nguyen

Abstract For chronic hepatitis B (CHB), alanine aminotransferase (ALT) ≥2 × upper limit of normal (ULN) is often used as a major criteria to initiate treatment in absence of cirrhosis, though patients with lower ALT may not be free from future risk of hepatocellular carcinoma (HCC). We aimed to examine the effect of antiviral therapy on HCC incidence based on ALT levels. We performed a retrospective study on 3665 patients consisting of United States and Taiwanese REVEAL-HBV cohort who were consecutive, treatment-naïve, noncirrhotic CHB patients aged ≥40 years. Patients were categorized by ALT cutoffs (≥2 × ULN vs <2 × ULN) and subgrouped by treatment status. Kaplan–Meier and Cox proportional hazards models were used to calculate cumulative incidence and hazard ratio (HR) of HCC adjusting for REACH-B scores. A total of 202 patients developed HCC. Antiviral treatment significantly reduced HCC risk: HR 0.24, 95% confidence interval 0.10–0.58; P = 0.001. HCC incidence per 100,000 person-years was significantly higher in untreated versus treated patients, even for those with ALT < 2 × ULN: 314.46 versus 0 per 100,000 person-years, P = 0.0042. For patients with Hepatitis B Virus (HBV) Deoxyribonucleic Acid (DNA) ≥ 2000 IU/mL, the number-needed-to-treat (NNT) were 15 and 14 to prevent 1 incident HCC at year 10 for patients with ALT < 2 × ULN and ≥2 × ULN, respectively. After adjustment by REACH-B score, antiviral treatment significantly decreased HCC incidence even in patients with ALT < 2 × ULN. NNT to prevent 1 incident HCC after 10 years of therapy was low (14–15) in patients with mildly elevated HBV DNA ≥ 2000 IU/mL regardless of ALT levels.


European Journal of Gastroenterology & Hepatology | 2015

Tenofovir monotherapy after achieving complete viral suppression on entecavir plus tenofovir combination therapy.

Lily H. Kim; Kevin T. Chaung; Nghiem B. Ha; Kevin C. Kin; Vinh Vu; Huy N. Trinh; Huy A. Nguyen; Mindie H. Nguyen

Objectives It is unclear whether patients with chronic hepatitis B with partial response to entecavir (ETV) who have achieved complete viral suppression (CVS) with ETV plus tenofovir (TDF) combination therapy maintain CVS if switched to TDF or ETV. Our goal was to examine virologic outcomes in such patients. Methods This is a retrospective cohort study of 57 ETV partial responders with chronic hepatitis B who showed CVS on ETV+TDF combination therapy, who were switched back to monotherapy with either ETV (n=16) or TDF (n=18), or continued on combination therapy (n=23). The majority of patients were Asian (91%) and male (65%), with a mean age of 41±12 years. Results The patients switched back to ETV had significantly higher rates of virologic breakthrough by 6 months after the switch compared with their TDF counterparts (88 vs. 39%, P=0.004). Patients who remained on ETV+TDF also had virologic breakthrough, due to either confirmed or suspected nonadherence. On multivariate analysis inclusive of age, sex, and hepatitis B virus DNA levels at initiation of combination therapy, ETV (compared with TDF) was found to be an independent predictor for virologic breakthrough (odds ratio 112.7, P=0.03), as well as duration of CVS of less than 12 months while on ETV+TDF (odds ratio 60.2, P=0.03). Conclusion TDF monotherapy, especially in those who have had CVS for at least 12 months on combination therapy, may be considered for some ETV partial responders who have achieved CVS with combination therapy, given the financial advantage and convenience of monotherapy.


Journal of Clinical Gastroenterology | 2016

Alternative Therapies for Chronic Hepatitis B Patients With Partial Virological Response to Standard Entecavir Monotherapy.

Kevin T. Chaung; Connor O'Brien; Nghiem B. Ha; Nghia Nguyen; Huy N. Trinh; Mindie H. Nguyen

Background: Entecavir (ETV) is a first-line, oral antinucleoside agent for the treatment of chronic hepatitis B patients. Despite its high potency, some patients may still be viremic after prolonged therapy with ETV monotherapy. Long-term outcome data comparing maintained ETV monotherapy to alternative therapies in persistently viremic patients are limited. Our goal was to compare complete viral suppression (CVS) rates [hepatitis B DNA (HBV DNA)<40 to 60 IU/mL] with alternative therapies to continued ETV monotherapy in ETV partial responders. Methods: This is a retrospective cohort study consisting of 86 consecutive treatment-naive, ETV=0.5 mg partial responders (detectable HBV DNA after ≥12 mo on ETV) who maintained ETV=0.5 mg daily (n=29) or switched to either ETV=1.0 mg daily (n=32) or ETV/tenofovir (TDF)=0.5 mg/300 mg (n=25) in 3 US GI/liver clinics from January 2005 to January 2012. Patients were identified by International Classification of Diseases, Ninth Revision query and data were collected by individual chart review. For those who remained on ETV=0.5 mg, comparison at regimen “switch time” was done using values at 12 months from initial ETV therapy. Rates of CVS were evaluated using Kaplan-Meier methods. Multivariate Cox proportional hazard models were used to estimate hazard ratio (HR) relating to potential predictors to the desirable outcomes of CVS. Results: In all therapy groups, the majority of patients were Asian (93.1% to 100.0%), male (64.0% to 68.8%), and hepatitis B e antigen-positive (95.8% to 100.0%) and had similar baseline alanine aminotransferase (ALT) levels. However, baseline HBV DNA (7.0 vs. 7.9 vs. 7.8 log10 IU/mL, P=0.05) and HBV DNA at regimen switch point (2.9 vs. 3.7 vs. 3.6 log10 IU/mL, P=0.0014) were lower in the ETV=0.5 mg cohort compared with those switched to ETV=1.0 mg or ETV/TDF, respectively. The ETV=0.5 mg cohort also had the shortest duration of ETV=0.5 mg therapy before switch (11.8 vs. 13.5 vs. 19.2 mo, P<0.0001). After the switch point, more patients on ETV/TDF achieved CVS compared with those on ETV=0.5 mg or ETV=1.0 mg at month 6 (77.3% vs. 13.8% vs. 9.4%), month 12 (86.4% vs. 40.5% vs. 25.0%), and month 18 (100% vs. 70.2% vs. 33.3%). Compared with the ETV=0.5 mg and ETV=1.0 mg groups, the ETV/TDF group also had higher rates of ALT normalization at month 6 (73.0% vs, 46.4% vs. 63.0%), month 12 (79.7% vs. 69.5% vs. 77.9%), and month 18 (100.0% vs. 69.5% vs. 86.8%), respectively. The multivariate analyses, inclusive of baseline age and treatment duration on initial therapy with ETV=0.5 mg, indicated that the ETV/TDF combination (HR=12.19, P<0.0001) was independently and positively associated with CVS, whereas high HBV DNA levels at baseline (HR=0.77, P=0.02) and at switch point (HR=0.46, P=0.002) were negatively associated with CVS. ETV=1.0 mg dose was not a predictor for CVS compared with ETV=0.5 mg. Conclusions: Following adjustments for HBV DNA levels and prior treatment duration, ETV/TDF combination therapy independently predicted superior viral suppression and ALT normalization in partial responders to ETV=0.5 mg daily compared with ETV=0.5 mg or ETV=1.0 mg monotherapy. In patients who continued to be viremic after 12 months of ETV=0.5 mg, one third were still viremic after another 18 months on the same therapy. Alternative therapies should be considered for these patients.


Gastroenterology | 2013

Sa1006 Effectiveness of Oral Antiviral Therapy for Treatment-Naive Chronic Hepatitis B (CHB) in Routine Clinical Practice

Mindie H. Nguyen; Huy N. Trinh; Kevin T. Chaung; Vincent G. Nguyen; Hong Tang; Timothy Juday

Background: Liver cirrhosis is inevitable outcome triggered by consistent chronic inflammation. Recent studies have implied that liver cirrhosis accompanied with angiogenesis. Our previous studies demonstrated that celecoxib could reduce angiogenesis in hepatocellular carcinoma and gastric adenocarcinoma. However, the effect of celecoxib on the antiangiogenesis of cirrhotic liver is still controversial. Objective: To investigate the effect of celecoxib on angiogenesis of cirrhotic liver. Methods: Peritoneal injection of thiacetamide (TAA) was employed to induce liver cirrhosis (200 mg/kg every three days × 16 weeks). 36 male Sprague-Dawley rats were assigned to three groups: group 1 (TAA + celecoxib, n = 12) received TAA plus celecoxib (20 mg/kg/day) by gavage from the initiation of TAA administration on, group 2 (TAA, n = 12) received TAA plus placebo and group 3 (Control, n = 12) received injections of 0.9% saline (1mL i.p., every three days). Serum biochemistry for liver and kidney function parameters and serum prostaglandin E2 (PGE2) were determined. Portal pressure and mean artery pressure were also measured. Histopathological study and vascular casting by scanning electron microscope (SEM) of liver vascular were performed. Additionally, immunohistochemistry (IHC), quantitative real-time PCR (qRT-PCR) and western blot for CD31, vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR2), and Cyclooxygenase-2 (COX-2) were determined. Results: Compared with TAA group, the fibrotic areas of liver tissues in TAA+celecoxib group were significantly decreased by one fold (20.8 ± 1.5% vs. 10.6 ± 0.9%, p , 0.001). Histological sections, vascular casts of hepatic portal vein by SEM, IHC and qRT-PCR for CD31 showed that hepatic fibrosis was accompanied with significant neoangiogenesis in TAA group when compared with Control group (0.1502 ± 0.0143 vs. 0.0325 ± 0.0086 mm2, p , 0.001). Impressively, the increased vascular areas were greatly reduced after celecoxib treatment (0.0485 ± 0.0097 vs. 0.1502 ± 0.0143 mm2, p , 0.001). The up-regulation of VEGF and VEGFR-2, COX-2 and PGE2 induced by TAA administration were significantly inhibited after celecoxib treatment. Compared with TAA group, the portal pressure in TAA+celecoxib group was significantly decreased by 17.8% (14.88 ± 0.84 vs. 12.23 ± 1.09 mmHg, p , 0.001). No significant differences in arterial pressure, heart rate and liver and kidney function parameters were observed among three groups (p . 0.05). Conclusions: Anti-angiogenesis therapy with celecoxib ameliorated hepatic angiogenesis, portal pressure as well as fibrosis. This result suggested that celecoxib would be beneficial for the treatment of liver cirrhosis.


Gastroenterology | 2012

Sa1003 High Prevalence of Hepatitis C Virus in Ethnically Diverse Community Patients With Non-Liver Related Gastrointestinal Complaints

Kevin C. Kin; Brian Lin; Nghiem B. Ha; Kevin T. Chaung; Huy N. Trinh; Ruel T. Garcia; Khanh K. Nguyen; Huy A. Nguyen; Eduardo B. da Silveira; Brian S. Levitt; Mindie H. Nguyen

disease, were excluded. Ten cases excluding the exceptions mentioned above were selected as healthy controls. The research was approved by the ethics commission of our hospital and all subjects gave their informed consent prior to inclusion in the study. The recommended dose of sonazoid was injected intravenously, and liver segment 5-6 and the right kidney were viewed simultaneously on video images. The region of interest (ROI) focused on the kidney, and the point at which 80% of the ROI in the kidney was colored was set as 0 s. The time course was then divided by color images as red up to 5 s and yellow after 5 s, to create At-PI for the liver parenchyma. Based on the At-PI, the ratio of red area to the colored area of the whole liver was calculated using Image J imaging processing software. The ratio of red area and assessment by liver biopsy (F factor) were analyzed for trends using the Jonckheere-Terpstra test, whereas multiple comparisons were performed using the SteelDwass test. Moreover, the usability of At-PI for diagnosis of liver fibrosis was examined by ROC curve analysis. The liver markers albumin (Alb), platelets (PLT), and prothrombin time (PT%), and the red area of each case were compared to determine the correlation coefficients and significance of differences. US was performed by a single technologist to ensure the same conditions in all cases. Cases in which there was difficulty in visualizing the liver because of intracostal narrowing, etc., were excluded. [Results] The ratio of red area in each F factor increased with progression of liver fibrosis. The ratio of red area increased significantly with Alb, PLT, PT% (R2=0.31, P=0.028/ R2=0.45, P=0.0003/ R2= 0.51, P=0.0003). [Conclusion] Hepatic arterialization accompanying with liver fibrosis of chronic hepatitis C could be visualized by analysis using At-PI. In addition, progression of hepatic arterialization and F factor were correlated with Alb, PLT, and PT%, which are representative parameters of liver function. At-PI is a useful and convenient method because it permits visualization of hepatic arterialization with clear color images, and may be feasible for clinical use in the evaluation of liver function and progression of liver fibrosis in patients with chronic hepatitis C.


Gastroenterology | 2011

High Rate of Recurrent Hepatitis B Viremia Following Treatment-Induced Hepatitis B E Antigen (HBeAg) Seroconversion

Kevin T. Chaung; Nghiem B. Ha; Huy N. Trinh; Nghi B. Ha; Ruel T. Garcia; Huy A. Nguyen; Khanh K. Nguyen; Gabriel Garcia; Aijaz Ahmed; Emmet B. Keeffe; Mindie H. Nguyen

Purpose: In patients with HBeAgpositive chronic hepatitis B (CHB), one of the primary endpoints of therapy is HBeAg seroconversion; however, there is inconsistent data on the durability of HBeAg seroconversion following consolidation therapy. Our goal is to investigate the rate of recurrent HBV viremia in CHB patients after HBeAg seroconversion. Methods: We retrospectively studied 88 consecutive CHB patients who achieved treatment-induced HBeAg seroconversion among the 458 HBeAg-positive patients treated with various antiviral regimens at 3 GI and liver clinics in the U.S. between 3/1998 and 9/2010. HBeAg seroconversion was defined as loss of HBeAg and development of hepatitis B e antibody (anti-HBe). Recurrent HBV viremia was defined as reappearance of detectable HBV DNA (>100 IU/mL) from nadir in two consecutive laboratory tests. Results: Patients were stratified into two groups: Group I 49 patients who remained on therapy, and Group II 39 patients who discontinued therapy following HBeAg seroconversion. In both groups, the majority of patients were Asian (94-95%) and male (62-69%). Antiviral medications in which patients achieved HBeAg seroconversion included: lamivudine (23%), adefovir (34%), entecavir (36%), tenofovir (4%), adefovir+lamivudine (1%), and entecavir+tenofovir (2%). Median treatment duration before HBeAg seroconversion was similar in Group I and Group II (18 [1-86] vs. 21 [5-63] months, p=0.99). At the time of HBeAg seroconversion, compared to Group I, Group II was younger (37±10 vs. 41±12 years), had lower mean HBV DNA levels (0.27±0.78 vs. 0.95±1.69 log10 IU/mL), and median ALT levels (24 [8-60] vs. 30 [593] U/L). In Group II, the median duration of consolidation therapy before treatment discontinuation was 12 months (range, 1-55), in which 10 completed <6 months, 10 completed 6-11 months, and 19 completed ≥12 months. At time of treatment discontinuation, all patients in Group II had undetectable HBV DNA. The rate of recurrent HBV viremia was significantly higher in Group II compared to Group I (90% vs. 0%, p<0.0001). After a median of 3 (1-42) months off therapy, the mean HBV DNA level detected at time of recurrent HBV viremia was 4.11±1.92 log10 IU/mL. Conclusion: The majority of patients (90%) who discontinued therapy after achieving HBeAg seroconversion with undetectable HBV DNA by PCR experienced recurrent HBV viremia. Patients who remained on therapy achieved and maintained undetectable level of HBV DNA. Patients should be monitored closely for recurrent HBVwhen therapy is discontinued, despite achieving HBeAg seroconversion.

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Huy N. Trinh

California Pacific Medical Center

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Huy A. Nguyen

Chonnam National University

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Ruel T. Garcia

University of California

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Kevin C. Kin

Touro University Nevada

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Nghi B. Ha

University of California

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