ORIGINAL ARTICLE: HEPATOLOGY
Chronic Hepatitis B Virus Infection in Children and Adolescents in Japan
Haruki Komatsu, yAyano Inui, yTsuyoshi Sogo, yTomoyuki Tsunoda, and yTomoo Fujisawa
ABSTRACT Background: Hepatitis B e antigen (HBeAg) seroconversion is an important event in patients with chronic hepatitis B virus (HBV) infection. This study aimed to clarify the outcome of long-term follow-up of chronic HBV infection and the factors affecting HBeAg seroconversion in children in Japan. Methods: Patients who were first examined at our institution between 1980 and 2012, who were 10 years since we reported the long-term outcome of chronic HBV infection in Japanese children (15). The aim of the present study was to clarify the long-term outcome of pediatric chronic HBV infection and the factors affecting the achievement of HBeAg seroconversion in Japan.
METHODS Patients Patients who were first examined at Eastern Yokohama Hospital between 1980 and 2012, who were 105 copies per milliliter, and the immune clearance phase was defined as serum ALT level > 40 IU/L and fluctuating serum HBV DNA levels. The inactive carrier phase was defined as loss of HBeAg, ALT < 40 IU/L, and serum HBV DNA < 104 copies per milliliter, as previously proposed (2,9,16).
99
Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.
Komatsu et al
JPGN
Flare-up of hepatitis was defined as the elevation of serum ALT levels >500 IU/L during the follow-up period. Vertical transmission was defined as having a mother known to have chronic HBV infection. Horizontal transmission was defined as having regular household contact with a family member known to have chronic HBV infection.
Laboratory Assays Liver biochemistry and a-fetoprotein were monitored using conventional assays. Viral markers (HBsAg, HBeAg, anti-HBe, anti-HBs) were tested by enzyme-linked immunosorbent assay or RIA. Serum samples were obtained and stored at 808C. The serum HBV DNA level was quantitatively analyzed using a branched DNA probe assay before 1998 (lower detection limit 700,000 copies per milliliter), a transcription-mediated amplification assay between 1999 and 2001 (lower detection limit 5000 copies per milliliter), a Roche PCR assay (Amplicor HBV Monitor; Roche Diagnostics, Basel, Switzerland) between 2002 and 2007 (lower detection limit ¼ 2.6 log copies per milliliter), and a Roche PCR assay (COBAS TaqMan HBV version 2.0; Roche Molecular Systems, Pleasanton, CA) from 2008 onward (lower detection limit 2.1 log copies per milliliter). The 6 major genotypes of HBV (A–F) were identified by enzyme-linked immunosorbent assay (Immunis HBV Genotype; Institute of Immunology Co, Ltd, Tokyo, Japan) or a polymerase chain reaction (PCR)–invader assay (17,18).
Volume 60, Number 1, January 2015
TABLE 1. Patient characteristics N ¼ 205 Age at diagnosis, y Follow-up period, y Duration of HBV infection Sex, male (%) Route of transmission (%) Vertical Horizontal Unknown Genotype (%) N ¼ 185 A B C D F Ethnicity (%) Japanese Chinese Vietnamese Korean Filipino Thai Treatment (%)
0–20 (median 4.0) 0.5–35 (median 8.2) 0.9–37 (median 12) 112 (55) 159 (78) 32 (16) 14 (6) 3 20 158 2 2
(2) (11) (85) (1) (1)
186 7 6 3 2 1 43
(91) (3) (3) (1) (1) (1) (21)
HBV ¼ hepatitis B virus.
Statistical Analysis For univariate statistical tests of the differences between proportions (categorical variables such as sex, genotype C, maternal transmission, etc), the Pearson x2 test was used. For univariate tests of location (for continuous variables such as age and maximum serum liver enzyme activity level), the Kruskal-Wallis rank test was used. For multivariate tests, multinomial logistic regression was used for >2 classification categories (seroconversion with serum viral load categories). In pairwise univariate comparisons, the Mann-Whitney-Wilcoxon test was used for continuous factors and the Pearson x2 test was used for categorical factors. In pairwise multivariate comparisons, a multinomial logistic regression model was used. Kaplan-Meier analysis was used to compute nonparametric estimates of time to HBeAg seroconversion. Patients who had not achieved HBeAg seroconversion were censored. The time zero of being at risk was the diagnosis of chronic HBV infection. The log-rank test was used as the statistical method to compare the curves between treated and untreated patients. All of the statistical analyses were performed with STATA/MP software (version 13.1; StataCorp, College Station, TX). A P value of 0.05 or less was considered to indicate statistical significance for all tests.
RESULTS Patient Characteristics A total of 205 patients (boys/girls: 112/93, age at diagnosis: 0–20 years, median age 4 years, follow-up period 0.5–37 years, median 8.2 years, duration of HBV infection 0.9–37 years, median 12 years) were enrolled in this cohort study. Of the 205 patients, 9 (vertical: n ¼ 6, age 104 copies/mL
N ¼ 97
N ¼ 78
N ¼ 17
51 2 76/87 50
(52.6) (0–15) (87.4) (15–1149)
4 (4.1) 81 (83.5)
45 5 61/73 247
(57.7) (0.003–20) (83.6) (30–1390)
19 (24.4) 56 (71.8)
10 6 12/16 384
(58.8) (0.1–17) (75) (134–1042)
7 (41.2) 13 (76.5)
P Univariate 0.76 0.02 0.43 0.0001
Chronic Hepatitis B Virus Infection in Children and Adolescents in Japan
Haruki Komatsu, yAyano Inui, yTsuyoshi Sogo, yTomoyuki Tsunoda, and yTomoo Fujisawa
ABSTRACT Background: Hepatitis B e antigen (HBeAg) seroconversion is an important event in patients with chronic hepatitis B virus (HBV) infection. This study aimed to clarify the outcome of long-term follow-up of chronic HBV infection and the factors affecting HBeAg seroconversion in children in Japan. Methods: Patients who were first examined at our institution between 1980 and 2012, who were 10 years since we reported the long-term outcome of chronic HBV infection in Japanese children (15). The aim of the present study was to clarify the long-term outcome of pediatric chronic HBV infection and the factors affecting the achievement of HBeAg seroconversion in Japan.
METHODS Patients Patients who were first examined at Eastern Yokohama Hospital between 1980 and 2012, who were 105 copies per milliliter, and the immune clearance phase was defined as serum ALT level > 40 IU/L and fluctuating serum HBV DNA levels. The inactive carrier phase was defined as loss of HBeAg, ALT < 40 IU/L, and serum HBV DNA < 104 copies per milliliter, as previously proposed (2,9,16).
99
Copyright 2014 by ESPGHAN and NASPGHAN. Unauthorized reproduction of this article is prohibited.
Komatsu et al
JPGN
Flare-up of hepatitis was defined as the elevation of serum ALT levels >500 IU/L during the follow-up period. Vertical transmission was defined as having a mother known to have chronic HBV infection. Horizontal transmission was defined as having regular household contact with a family member known to have chronic HBV infection.
Laboratory Assays Liver biochemistry and a-fetoprotein were monitored using conventional assays. Viral markers (HBsAg, HBeAg, anti-HBe, anti-HBs) were tested by enzyme-linked immunosorbent assay or RIA. Serum samples were obtained and stored at 808C. The serum HBV DNA level was quantitatively analyzed using a branched DNA probe assay before 1998 (lower detection limit 700,000 copies per milliliter), a transcription-mediated amplification assay between 1999 and 2001 (lower detection limit 5000 copies per milliliter), a Roche PCR assay (Amplicor HBV Monitor; Roche Diagnostics, Basel, Switzerland) between 2002 and 2007 (lower detection limit ¼ 2.6 log copies per milliliter), and a Roche PCR assay (COBAS TaqMan HBV version 2.0; Roche Molecular Systems, Pleasanton, CA) from 2008 onward (lower detection limit 2.1 log copies per milliliter). The 6 major genotypes of HBV (A–F) were identified by enzyme-linked immunosorbent assay (Immunis HBV Genotype; Institute of Immunology Co, Ltd, Tokyo, Japan) or a polymerase chain reaction (PCR)–invader assay (17,18).
Volume 60, Number 1, January 2015
TABLE 1. Patient characteristics N ¼ 205 Age at diagnosis, y Follow-up period, y Duration of HBV infection Sex, male (%) Route of transmission (%) Vertical Horizontal Unknown Genotype (%) N ¼ 185 A B C D F Ethnicity (%) Japanese Chinese Vietnamese Korean Filipino Thai Treatment (%)
0–20 (median 4.0) 0.5–35 (median 8.2) 0.9–37 (median 12) 112 (55) 159 (78) 32 (16) 14 (6) 3 20 158 2 2
(2) (11) (85) (1) (1)
186 7 6 3 2 1 43
(91) (3) (3) (1) (1) (1) (21)
HBV ¼ hepatitis B virus.
Statistical Analysis For univariate statistical tests of the differences between proportions (categorical variables such as sex, genotype C, maternal transmission, etc), the Pearson x2 test was used. For univariate tests of location (for continuous variables such as age and maximum serum liver enzyme activity level), the Kruskal-Wallis rank test was used. For multivariate tests, multinomial logistic regression was used for >2 classification categories (seroconversion with serum viral load categories). In pairwise univariate comparisons, the Mann-Whitney-Wilcoxon test was used for continuous factors and the Pearson x2 test was used for categorical factors. In pairwise multivariate comparisons, a multinomial logistic regression model was used. Kaplan-Meier analysis was used to compute nonparametric estimates of time to HBeAg seroconversion. Patients who had not achieved HBeAg seroconversion were censored. The time zero of being at risk was the diagnosis of chronic HBV infection. The log-rank test was used as the statistical method to compare the curves between treated and untreated patients. All of the statistical analyses were performed with STATA/MP software (version 13.1; StataCorp, College Station, TX). A P value of 0.05 or less was considered to indicate statistical significance for all tests.
RESULTS Patient Characteristics A total of 205 patients (boys/girls: 112/93, age at diagnosis: 0–20 years, median age 4 years, follow-up period 0.5–37 years, median 8.2 years, duration of HBV infection 0.9–37 years, median 12 years) were enrolled in this cohort study. Of the 205 patients, 9 (vertical: n ¼ 6, age 104 copies/mL
N ¼ 97
N ¼ 78
N ¼ 17
51 2 76/87 50
(52.6) (0–15) (87.4) (15–1149)
4 (4.1) 81 (83.5)
45 5 61/73 247
(57.7) (0.003–20) (83.6) (30–1390)
19 (24.4) 56 (71.8)
10 6 12/16 384
(58.8) (0.1–17) (75) (134–1042)
7 (41.2) 13 (76.5)
P Univariate 0.76 0.02 0.43 0.0001
