Abstract
Introduction
The seroprevalence of hepatitis E virus (HEV) in patients with chronic liver disease (CLD) is little known in Brazil. Studies have suggested that HEV may harmfully influence the course of CLD, with a higher risk of progression to cirrhosis.
Objective
To estimate the prevalence of the anti-HEV antibody (IgG) in patients with CLD and to describe demographic data and risk factors, as well as clinical-laboratory and ultrasound parameters.
Patients and methods
Cross-sectional study that included 227 patients with CLD followed at a referral outpatient clinic from June 2022 to March 2023. The patients were investigated clinically and tested for liver functions, anti-HEV IgG and, in positive cases, for HEV-RNA. Ultrasonography of the upper abdomen was also carried out.
Results
Investigation of 227 patients (50 with hepatitis B, 49 with nonalcoholic fatty liver disease, 33 with hepatitis C, 17 with alcoholic liver disease, 16 with schistosomiasis and 62 with mixed disease), 55.5% were female, with an average age of 57 ± 13 years; 37.9% had liver cirrhosis. Seven patients (3.08%) presented anti-HEV positive and HEV-RNA negative. Ultrasound identified association between anti-HEV and contact with pigs, presence of gynecomastia or palmar erythema, lower platelet count, higher APRI and FIB-4 values, and splenomegaly.
Conclusion
Although the prevalence of anti-HEV in patients with CLD was low in this study, the antibody was observed more frequently in cases with a history of contact with pigs and with clinical-laboratory or imaging evidence of more advanced chronic liver disease.
Keywords: Hepatitis E virus, Hepatitis E, Seroprevalence, Liver cirrhosis
Introduction
The hepatitis E virus (HEV), a positive-sense, single-stranded RNA virus, is classified in the Hepeviridae family, genus Orthohepevirus, species A, with eight genotypes currently recognized (HEV-1 to HEV-8). Genotypes HEV-1 to HEV-4 have been detected in humans, while HEV-5 and HEV-6 are genotypes strictly found in wild boars; and genotypes HEV-7 and HEV-8 are found in camels and dromedaries [1]. Two of these genotypes (HEV-1 and HEV-2) only infect humans. The HEV-3 and HEV-4 genotypes are endemic in animal species such as pigs and wild boars; These strains cause zoonotic infections in humans, through the consumption of contaminated meat or direct contact [2].
Contagion by the HEV-1 and HEV-2 genotypes occurs through the oral-fecal route, by consumption of contaminated water, causing diseases in areas with fragile sanitary infrastructure, as occurs in India. Sporadic cases are common, but can be responsible for large outbreaks, involving hundreds or thousands of cases [3].
The HEV-3 and HEV-4 genotypes infect humans sporadically as accidental hosts, through the consumption of contaminated pork products, causing normally asymptomatic infections in immunocompetent patients. These genotypes may progress to chronic hepatitis and cirrhosis of the liver in immunocompromised patients, such as transplant recipients and people living with HIV. Occasionally, infection may be associated with extrahepatic manifestations: neurological and hematological [4].
In recent years, HEV has drawn attention with increased reporting of autochthonous cases of hepatitis from industrialized countries. Hepatitis E had been considered a rare disease in these countries and observed only in travelers returning from endemic areas in Africa and Asia. The autochthonous cases described in industrialized countries were caused by the HEV-3 and HEV-4 genotypes, with epidemiological and clinical characteristics distinct from the HEV-1 and HEV-2 genotypes, which were already circulating in developing countries [5].
HEV is the leading cause of acute enterically transmitted hepatitis worldwide [6]. According to the latest WHO report, HEV is responsible for about 20 million infections per year, with more than 3 million symptomatic infections and 44,000 deaths worldwide in 2015 [7]. In a meta-analysis carried out to evaluate the global prevalence of HEV, involving 287 studies and 1,099,717 patients, a percentage of anti-HEV IgG of 12.47% was found. Data were stratified to estimate the prevalence of anti-HEV in 75 countries across six continents. The highest rate of anti-HEV IgG seropositivity was found in Africa (21.76%), followed by Asia (15.80%), Europe (9.31%), North America (8.05%), South America (7.28%) and Oceania (5.99%). Data were also collected in relation to genotyping, with the finding that genotype 1 infection occurred commonly in India and occasionally in China, and that genotype 3 was widely distributed in European countries [8].
In Brazil, a systematic review published in 2019 identified a global seroprevalence of HEV of 6% (95% CI: 5.0–7.0), but with great heterogeneity between studies (86.7%), ranging from 0% (95% CI: 0.0–3.0) to 10% (95% CI: 7.0–15.0). In the subgroup analysis, the prevalence of anti-HEV was 7% in blood donors and 3% in the general population [9], suggesting that HEV infection in Brazil is not rare.
Chronic infection with HEV genotype 3 is found in immunocompromised patients in European countries. In solid organ transplant recipients, HEV RNA positive active infection, has been detected in 1 to 2% of cases [10]. Although the exact amount of chronicity is different between the various studies, it is assumed that HEV infections become chronic in about two-thirds of solid organ recipient patients [11].
Little is known about the prevalence of HEV in patients with chronic liver disease (CLD). A study of anti-HEV IgG seroprevalence conducted in California, USA, found a rate of 6.6% in patients with alcohol-associated CLD, 8.7% in patients with hepatitis C, 8.8% in patients with nonalcoholic fatty liver disease (NAFLD) and 19.9% in patients with hepatitis B [12]. Another study, conducted in Vienna, Austria, found a prevalence of 26.3% of anti-HEV IgG in patients with NAFLD, with seropositivity being independently associated with a higher risk of cirrhosis [13]. Although restricted to a single etiology for liver cirrhosis, the study suggests that the association of HEV with CLD may negatively influence the progression of the disease to cirrhosis.
Due to the possibility of worsening of CLD by the hepatitis E virus, this study aimed to verify the prevalence of anti-HEV IgG and its association with demographic data, risk factors, clinical-laboratory and ultrasonographic exams in patients with CLD of different etiologies followed in a Hepatology outpatient clinic of a reference hospital in Recife-PE.
Material and methods
Study design
This is a cross-sectional study, developed at the Hepatology Outpatient Clinic of the Hospital das Clínicas of the Federal University of Pernambuco (HC-UFPE).
Patients
The minimum sample size for the development of the study was 134 patients. The sample size calculation was performed using the EPI-INFO program version 7.2.2.16, establishing an error of 5%, reliability of 95% and expected proportion of anti-HEV IgG of 8.61% in patients with CLD [12].
We included patients older than 18 years, with a diagnosis of CLD of the following etiologies: NAFLD, alcoholic, hepatitis B, hepatitis C, schistosomiasis and mixed disease (more than one etiology) who were seen between June 2022 and March 2023. Schistosomiasis was diagnosed by personal history and presence of periportal fibrosis identified by ultrasound. Patients diagnosed with acute liver diseases, liver or kidney transplants, people living with HIV/AIDS or using immunosuppressants were excluded.
Method
After signing the Free and Informed Consent Form, the patients were submitted to an interview to collect sociodemographic data and risk factors. Subsequently, a physical examination was performed to evaluate stigmas or signs of chronic liver disease, portal hypertension or cirrhosis decompensation. Then, 5 mL of blood was collected from a peripheral vein for use in anti-HEV research. ELISA commercial kits (EUROIMMUN®, Germany) were used, and examined at the Virology Laboratory of Keizo Asami Institute (LIKA-UFPE). In patients with positive anti-HEV IgG, HEV RNA was tested by real-time PCR using the RealStar kit (HEV RT-PCR kit 2.0, Altona Diagnostics®, Germany), in the Virology Laboratory of Albert Einstein Diagnostic Medicine.
The following complementary tests were performed within 3 months of blood collection. The serum activities of aminotransferases (ALT and AST), bilirubin, Gamma-GT, Albumin, platelet count and INR (International Normalized Ratio). These were analyzed in the central laboratory of HC-UFPE. Ultrasonography of the upper abdomen was performed at HC-UFPE by two experienced examiners.
The study was approved by the Ethics and Research Committee of HC-UFPE, number: 5.324.465 and Certificate of Presentation of Ethical Appreciation number: 55401222.0.0000.8807.
Statistical analysis
Clinical and laboratory data were transcribed in spreadsheet form and analyzed using IBM SPSS® 26 Statistics, for Windows, and MedCalc® 20.104 statistical software. Quantitative variables were described as mean and standard deviations or median and 25th and 75th percentiles, depending on the result of the Shapiro–Wilk normality test. Qualitative variables were described as absolute and relative frequencies.
Patients were divided into two groups (positive and negative anti-HEV IgG). Chi-square test and Fisher's exact test were used to compare categorical variables. The comparison of means between two independent groups with normal distribution was based on the unpaired t-test, whereas the comparison of medians between non-parametric variables was made through Mann–Whitney test. Association between exposure (potential risk factors) and outcomes (positive or negative anti-HEV IgG) was analyzed using prevalence ratio (PR) at a 95% confidence interval (95% CI). This coefficient is used as an estimate of odds ratio in cross-sectional studies with low-frequency outcomes to estimate the chances of these results in exposed and unexposed subjects [14]. Results with p < 0.05 were considered statistically significant.
Results
A total of 227 patients met the inclusion criteria, of which 126 (55.5%) were female, with an average age of 57 ± 13 years. The other demographic characteristics are shown in Table 1.
Table 1.
Demographic characteristics and risk factors of 227 patients with chronic liver disease, according to anti-HEV IgG serology,Recife, 2023
| Variables | Anti-HEV IgG | p | RP | 95% CI | pd | Total | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Positive | Negative | |||||||||
| n | % | n | % | n | % | |||||
| Sexo | ||||||||||
| Male | 4 | 57.10% | 97 | 44.10% | 0.703a | 1.66 | 0.38–7.26 | 0.499 | 101 | 44.50% |
| Female | 3 | 42.90% | 123 | 55.90% | 126 | 55.50% | ||||
| Idade* | 57 | ± 11 | 57 | ± 13 | 0.962b | − | − | − | 57 | ± 13 |
| Etnia | ||||||||||
| Black | 1 | 14.30% | 15 | 6.80% | 0.556c | − | − | − | 191 | 84.10% |
| Mixed | 6 | 85.70% | 185 | 84.10% | 1.99 | 0.25–15.5 | 0.512 | 16 | 7.00% | |
| White | 0 | 0.00% | 20 | 9.10% | 3.71 | 0.16–85.3 | 0.413 | 20 | 8.80% | |
| Native | 0 | 0.00% | 0 | 0.00% | 0.17 | 0.01–2.12 | 0.171 | 0 | 0.00% | |
| Treated water | ||||||||||
| Yes | 7 | 100.00% | 196 | 89.10% | 1.000a | 1.84 | 0.11–31.2 | 0.674 | 203 | 89.40% |
| No | 0 | 0.00% | 24 | 10.90% | 24 | 10.60% | ||||
| Sanitation | ||||||||||
| Yes | 6 | 85.70% | 166 | 75.50% | 1.000a | 1.92 | 0.24–15.6 | 0.542 | 172 | 75.80% |
| No | 1 | 14.30% | 54 | 24.50% | 55 | 24.20% | ||||
| Education | ||||||||||
| Illiterate | 0 | 0.00% | 16 | 7.30% | 0.204c | − | − | − | 16 | 7.10% |
| Elementary school | 3 | 42.90% | 124 | 56.60% | 1.07 | 0.06–19.9 | 0.961 | 127 | 56.20% | |
| High school | 2 | 28.60% | 63 | 28.80% | 0.78 | 0.04–15.5 | 0.868 | 65 | 28.80% | |
| Higher education | 2 | 28.60% | 16 | 7.30% | 0.22 | 0.01–4.3 | 0.322 | 18 | 8.00% | |
| Contact with pigs | ||||||||||
| Yes | 5 | 71.40% | 53 | 24.20% | 0.013a | 7.24 | 1.44–36.3 | 0.016 | 58 | 25.70% |
| No | 2 | 28.60% | 166 | 75.80% | 168 | 74.30% | ||||
| Consumption of pigs | ||||||||||
| Yes | 4 | 57.10% | 121 | 55.30% | 1.000a | 1.07 | 0.25–4.7 | 0.921 | 125 | 55.31% |
| No | 3 | 42.90% | 98 | 44.70% | 101 | 44.69% | ||||
aFisher's Exact Test; b,unpaired t-Test; c Chi-Square test; dZ test
*Expressed as mean ± SD
95% CI 95% confidence interval; PR Prevalence ratio
Anti-HEV IgG testing was positive in 7 of the 227 (3.08%) patients with CLD; HEV-RNA testing was negative in all patients. The risk factors of the 227 patients according to the serology for anti-HEV are shown in Table 1. Only contact with pigs showed an association with the presence of anti-HEV-IgG (p = 0.013). Thus, it can be inferred that patients who had contact with pigs ran a risk at least 7.24 times greater of having anti-HEV IgG, when compared to those who had no contact with pigs, and that this increase was statistically significant (p = 0.016).
The clinical characteristics of the 227 patients with CLD are described in Table 2. An association was observed between anti-HEV-IgG and the presence of gynecomastia (p = 0.041) and palmar erythema (p = 0.07). Thus, it can be inferred that patients with gynecomastia and erythema presented a risk at least 7.62 and 4.27 times greater, respectively, of having anti-HEV, when compared to those who did not have gynecomastia or erythema, and that this increase was significant (p = 0.009 and p = 0.049, respectively).
Table 2.
Clinical characteristics of 227 patients with chronic liver disease, according to anti-HEV IgG serology, Recife, 2023
| Variables | Anti-HEV IgG | pa | RP | CI 95% | pb | Total | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| Positive | Negative | |||||||||
| n | % | n | % | n | % | |||||
| Jaundice | ||||||||||
| Yes | 1 | 14.30% | 31 | 14.10% | 1.000 | 1.02 | 0.13–8.16 | 0.988 | 32 | 14.10% |
| No | 6 | 85.70% | 189 | 85.90% | 195 | 85.90% | ||||
| Ascites | ||||||||||
| Yes | 0 | 0.00% | 15 | 6.80% | 1.000 | 0.89 | 0.05–14.8 | 0.933 | 15 | 6.60% |
| No | 7 | 100.00% | 205 | 93.20% | 212 | 93.40% | ||||
| Erythema | ||||||||||
| Yes | 3 | 42.90% | 30 | 14.00% | 0.070 | 4.27 | 1.0–18.2 | 0.049 | 33 | 14.90% |
| No | 4 | 57.10% | 184 | 86.00% | 188 | 85.10% | ||||
| Spider | ||||||||||
| Yes | 2 | 28.60% | 20 | 9.30% | 0.146 | 3.82 | 0.79–18.5 | 0.096 | 22 | 10.00% |
| No | 5 | 71.40% | 194 | 90.70% | 199 | 90.00% | ||||
| Gynecomastia | ||||||||||
| Yes | 2 | 28.60% | 9 | 4.20% | 0.041 | 7.63 | 1.66–35.0 | 0.009 | 11 | 5.00% |
| No | 5 | 71.40% | 205 | 95.80% | 210 | 95.00% | ||||
| Hair rarefaction | ||||||||||
| Yes | 1 | 14.30% | 14 | 6.50% | 0.393 | 2.29 | 0.29–17.8 | 0.429 | 15 | 6.80% |
| No | 6 | 85.70% | 200 | 93.50% | 206 | 93.20% | ||||
| Cirrhosis | ||||||||||
| Yes | 5 | 71.40% | 81 | 36.80% | 0.108 | 4.09 | 0.81–20.7 | 0.087 | 86 | 37.9% |
| No | 2 | 28.60% | 139 | 63.20% | 141 | 62.1% | ||||
aFisher's Exact test; bZ test
95% CI 95% confidence interval; PR Prevalence ratio
According to the etiology of CLD, patients had the following distribution: 50 with hepatitis B, 49 with NAFLD, 33 with hepatitis C, 17 with alcoholic liver disease, 16 with schistosomiasis and 62 with mixed disease (more than one etiology). Eighty-six (37.9%) of them already had liver cirrhosis (Table 3). Anti-HEV IgG was not more frequent in patients with cirrhosis (p = 0.114).
Table 3.
Distribution of the etiological of chronic liver disease in the 227 patients, according to anti-HEV IgG serology, Recife, 2023
| Etiology of the chronic liver disease | Anti-HEV-IgG | p * | Total | ||||
|---|---|---|---|---|---|---|---|
| Positive | Negative | ||||||
| n | % | n | % | n | % | ||
| Hepatitis B | 0 | 0,00% | 50 | 22,70% | 0,126 | 50 | 22,00% |
| DHGM | 0 | 0,00% | 49 | 22,30% | 49 | 21,60% | |
| Hepatitis C | 1 | 14,30% | 32 | 14,50% | 33 | 14,50% | |
| Alcohol, | 2 | 28,60% | 15 | 6,80% | 17 | 7,50% | |
| Schistosomiasis | 1 | 14,30% | 15 | 6,80% | 16 | 7,00% | |
| Chronic liver disease mixed | 3 | 42,90% | 59 | 26,80% | 62 | 27,30% | |
| Alcohol + Schistosomiasis | 1 | 33.33% | 7 | 11,86% | 8 | 12,90% | |
| Hepatitis B + Schistosomiasis | 1 | 33.33% | 2 | 3,39% | 3 | 4,84% | |
| Hepatitis C + Schistosomiasis | 1 | 33.33% | 5 | 8.47% | 6 | 9,68% | |
| -NAFLD + schistosomiasis | 0 | 0,00% | 4 | 6,78% | 4 | 6,45% | |
| -Other | 0 | 0,00% | 41 | 69,49% | 41 | 66,13% | |
*The Chi-Square test. NAFLD Nonalcoholic fatty liver disease
The 7 patients with positive anti-HEV IgG had the following etiologies of CLD: 2 with alcoholic liver disease, 1 with hepatitis C, 1 with schistosomiasis, 1 with hepatitis C and schistosomiasis, 1 with alcoholic liver disease and schistosomiasis and 1 with hepatitis B and schistosomiasis. Four of the 7 patients with positive anti-HEV (p = 0.021) had schistosomiasis as the etiology of CLD (Table 3).
In the laboratory (Table 4) and imaging (Table 5) evaluations, an association was observed between anti-HEV-IgG and lower platelet counts (p = 0.006), higher APRI values (p = 0.011) and FIB 4 (p = 0.007). On ultrasonography, an association was observed between anti-HEV and splenomegaly (p = 0.04).
Table 4.
Laboratory characteristics of 227 patients with chronic liver disease, according to anti-HEV IgG serology, Recife, 2023
| Variable | Anti-HEV-IgG | p | Total | ||||
|---|---|---|---|---|---|---|---|
| Positive | Negative | ||||||
| n, | % | n, | % | n, | % | ||
| Platelet count (/mm3)* | 99.571 | ± 91.659 | 180.971 | ± 75.273 | 0.006a | 178.283 | ± 77.004 |
| INR* | 1,31 | ± 0,26 | 1,16 | ± 0,25 | 0,126a | 1,17 | ± 0,26 |
| ALT (IU/L)* | 33 | (26–44) | 33 | (23–49) | 0,900b | 33 | (23–47) |
| AST (IU/L)* | 43 | (29–46) | 31 | (24–47) | 0,280b | 31 | (24–46) |
| BT (mg/dL)** | 0.96 | (0,87- 1.6) | 0.7 | (0,46–1,1) | 0,061b | 0.72 | (0.46- 1.13) |
| FA (IU/L) * | 101 | (71–118) | 77 | (58–96) | 0,308b | 77 | (58–97) |
| GGT (IU/L)* | 88 | (61–165) | 49 | (29–110) | 0,111b | 50 | (29–116) |
| ALB (g/dL)** | 4 | (3,4–4,5) | 4,3 | (3,9–4,5) | 0,322b | 4.3 | (3.9—4.5) |
| APRI** | 1.47 | (0.55 -1.69) | 0,45 | (0,27–0,85) | 0,011b | 0,46 | (0,27–0,87) |
| FIB-4** | 6,00 | (2,69–9,15) | 1,76 | (1,02–3,66) | 0,007b | 1,78 | (1,03–3,77) |
| Child–Pugh classification | |||||||
| A | 4 | 80.00% | 53 | 75,70% | 0,893c, | 57 | 76.00% |
| B | 1 | 20,00% | 14 | 20,00% | 15 | 20,00% | |
| C | 0 | 0,00% | 3 | 4,30% | 3 | 4,00% | |
| MELD | |||||||
| ≤ 9 | 2 | 40,00% | 34 | 48,60% | 0,755c | 36 | 48,00% |
| 10 -19 | 3 | 60,00% | 32 | 45,70% | 35 | 46,70% | |
| ≥ 20 | 0 | 0,00% | 4 | 5,70% | 4 | 5,30% | |
aunpaired t-Test; bMann-Whitney u test. c−Chi-Square test
*Expressed as mean ± SD; **Values at the median (P25-P75). ALB Albumin; ALT Alanine aminotransferase; APRI The index of the relationship of normal for the institution on the platelet count; AST Aspartate aminotransferase; FA Alkaline phosphatase; FIB-4 Index and fibrosis-4; GGT Gamma-glutamyl transferase; INR International normalized ratio; MELD Model for liver disease end-stage
Table 5.
Imaging characteristics of patients with chronic liver disease, according to anti-HEV IgG serology, Recife, 2023
| Variables | Anti-HEV IgG | p | Total | |||||
|---|---|---|---|---|---|---|---|---|
| Positive | Negative | |||||||
| n | % | n | % | n | % | |||
| US, irregularity of the surface | ||||||||
| Missing | 2 | 28,60% | 92 | 52,30% | 0,310a | 94 | 51,40% | |
| Lighter | 1 | 14,30% | 26 | 14,80% | 27 | 14,80% | ||
| Crude | 0 | 0,00% | 12 | 6,80% | 12 | 6,60% | ||
| Lobulada | 4 | 57,10% | 46 | 26,10% | 50 | 27.3% | ||
| US, texture, | ||||||||
| Homogeneous | 2 | 28,60% | 88 | 50,00% | 0,444a | 90 | 49,20% | |
| Heterogeneous | 5 | 71,40% | 88 | 50,00% | 93 | 50,80% | ||
| Spleen (cm)* | 13.4 | (12.0 a-17,7) | 12,0 | (9.7–12.0 a) | 0,044b | 12.0 | 9.7–12.2) | |
| Portal vein (cm.) * | 1,2 | (0,90–1,60) | 1,1 | (0,96–1,20) | 0,372b | 1,1 | (0,96–1,20) | |
| Side - | Yes | 2 | 28,60% | 14 | 8,00% | 0,119c | 16 | 8,80% |
| No | 5 | 71,40% | 160 | 92,00% | 165 | 91,20% | ||
| Ascites | Sim | 1 | 14,30% | 14 | 8,00% | 0,460c | 15 | 8,30% |
| No | 6 | 85,70% | 160 | 92,00% | 166 | 91,70% | ||
aChi-Square Test; b−Test, Mann–Whitney u test; c,Fisher's Exact Test;
*The values in the median (P25-P75). US Ultrasonography
Discussion
In recent years, there has been a growing interest in HEV infection and its repercussions, such as the possible association with more severe liver diseases. Given this, our study was developed to evaluate the occurrence of anti-HEV in patients with CLD from a reference center in Recife, Pernambuco.
We found 7 cases (3.08%) with positive anti-HEV among the 227 patients with CLD and all presented negative HEV-RNA research.
Serological surveys on HEV carried out in Brazil, in blood donors, have revealed the following results. In Pernambuco the prevalence of anti-HEV IgG was found to be 0.9% [15], in Mato Grosso 4% [16], in São Paulo 9.8% [17], while in Rio Grande do Sul prevalence of 40.25% [18] and in Santa Catarina 10% [19]. The highest seroprevalence, detected in the South of Brazil, is explained because it is the region with the highest activity in pig farming and the highest consumption of pork and pork products.
Due to the chronification of HEV in immunosuppressed people, the number of investigations of these patients has increased. In people living with HIV, seroprevalence of anti-HEV IgG has been found to be 4.1% in Pernambuco [20], in Rio Grande do Sul 6.7% [21] and in São Paulo 10.7% [22].
Among renal transplant recipients, the seroprevalence of anti-HEV IgG was found to be 2.5% in Goiás [23] and 3.1% [24] and 15% [25] in two medical centers in São Paulo. In these two studies from São Paulo, HEV-RNA was found, respectively, in 3.1% [24] and 10% [25] of the transplant recipients. among liver transplant recipients, the seroprevalence of anti-HEV IgG was 8.1% in São Paulo [26].
A retrospective multicenter study, with data from 17 centers in Europe and the United States, evaluated 85 HEV-infected solid organ transplant recipients. Of these, 56 patients (65.9%) developed chronic hepatitis, 8 patients (9.4%) developed liver cirrhosis and 2 died from complications of cirrhosis [27].
A study conducted in Bahia revealed a prevalence of 12.95% of anti-HEV IgG in 301 patients with CLD. The etiologies included were hepatitis B, hepatitis C, autoimmune hepatitis, and drug-induced liver injury (DILI). When stratified by groups, drug-induced liver injury had the highest prevalence (21.1%) of anti-HEV [28]. It is possible that the differences in the tested population may have been responsible for the higher prevalence of anti-HEV in Bahia, in relation to the prevalence found in our study. In addition, the distribution of the etiologies of CLD was different in the two states, since in Bahia patients with autoimmune hepatitis and DILI were included, being the most frequent anti-HEV in those with DILI.
In the present study, gender and age were not associated with the presence of anti-HEV IgG. However, some authors have suggested that advanced age and male gender may be associated with anti-HEV seroprevalence, possibly due to greater exposure throughout life [12].
Regarding risk factors, in this study there was an association between anti-HEV IgG and contact with pig farming, but no association was observed related to the ingestion of pork meat. A study in Pernambuco revealed positivity of anti-HEV IgG in 81.25% of the 96 pigs sent to slaughterhouses [29]. This confirms the frequent occurrence of HEV in our country. There did not seem to be any association of anti-HEV IgG with pork intake, possibly due to the fact that pork is usually well cooked in our environment. In addition, pork has a high cost and this study involved patients from the public system, who have lower purchasing power and more restricted pork consumption.
However, a Brazilian study conducted with 80 patients with schistosomiasis mansoni, found anti-HEV IgG in 15 cases (18.8%). This high prevalence was attributed to the involvement of almost 1/3 of schistosomal patients with advanced patterns of fibrosis and portal hypertension. These cases are subject to more episodes of digestive bleeding and, consequently, greater exposure to hospital environments and endoscopic procedures [30]. In fact, in our study, a higher occurrence of anti-HEV was also observed in cases with CLD involving schistosomiasis mansoni in the etiology.
Additionally, other studies have shown a higher prevalence of anti-HEV IgG in patients with cirrhosis when compared to those with less advanced stage CLD. In fact, Paternostro et al. evaluated 167 patients with NAFLD and observed 44 (26.3%) patients with positive anti-HEV IgG, being the most frequent antibody in those with cirrhosis (18.2 vs 6.5%, p = 0.024) [13]. In another study involving patients with hepatitis C, a higher prevalence of anti-HEV IgG was also found in cirrhotic patients (13.2% vs 8%, OR:1.74, p = 0.04) [31].
In our study, no association of anti-HEV IgG with cirrhosis was found. An association was detected, however, with some variables related to more advanced CLD. For example, physical examinations of the participants identified an association of anti-HEV IgG with gynecomastia and a tendency to association with palmar erythema (p = 0.07). In addition, patients with gynecomastia or erythema were more likely to present IgG antibody against HEV. These stigmata of chronic liver disease are due to hyperestrogenism, which is common in liver failure.
In the laboratory evaluation, there was an association of anti-HEV IgG with thrombocytopenia, one of the first laboratory manifestations of portal hypertension. Ultrasound examinations also showed a larger size of the spleen in cases with positive anti-HEV, which could be related to hypersplenism.
Bilirubin serum levels increased in cases with anti-HEV, at values close to significant (p = 0.061), which also reflects more advanced CLD. Perhaps, the number of cases with positive anti-HEV found in this study was insufficient to reveal greater laboratory evidence of more advanced liver disease; or, possibly, the number of cirrhotic patients was insufficient to reveal differences, constituting limitations of this research.
APRI and FIB-4 values were also higher in those patients with positive anti-HEV IgG. Certainly, these scores indicated more advanced fibrosis in cases where anti-HEV was induced by thrombocytopenia, since no differences were observed in serum aminotransferase levels. Additionally, similar serum levels of aminotransferases between cases with and without anti-HEV could have been related to the absence of inflammatory activity caused by HEV, since all cases with CLD in our study had undetectable HEV-RNA.
The higher occurrence of anti-HEV IgG associated with these clinical, laboratory and imaging findings, taken together, suggests that HEV is related to more advanced CLD. However, by the design of this study, it was not possible to verify the causal relationship between HEV and more severe CLD.
Conclusion
Although the prevalence of anti-HEV in patients with CLD was low in this study, the antibody was observed more frequently in cases with a history of contact with pigs and clinical-laboratory or imaging evidence of more advanced liver disease.
Declarations
Conflict of interest
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Contributor Information
Lílian Rose Maia Gomes de Araújo, Email: maia_lilian@hotmail.com.
Edmundo Pessoa Lopes, Email: epalopes@uol.com.br.
References
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