Brief Report: HIV/HBV Coinfection is a Significant Risk Factor for Liver Fibrosis in Tanzanian HIV-Infected Adults

Abstract

Background: 

In sub-Saharan Africa, the burden of liver disease associated with chronic hepatitis B virus (HBV) and HIV is unknown. We characterized liver disease using aspartate aminotransferase-to-platelet ratio index (APRI) and FIB-4 in patients with HIV, HBV, and HIV/HBV coinfection in Tanzania.

Methods: 

Using a cross-sectional design, we compared the prevalence of liver fibrosis in treatment-naive HIV monoinfected, HBV monoinfected, and HIV/HBV-coinfected adults enrolled at Management and Development for Health (MDH)-supported HIV treatment clinics in Dar es Salaam, Tanzania. Risk factors associated with significant fibrosis (APRI >0.5 and FIB-4 >1.45) were examined.

Results: 

Two hundred sixty-seven HIV-infected, 165 HBV-infected, and 63 HIV/HBV-coinfected patients were analyzed [44% men, median age 37 (interquartile range 14), body mass index 23 (7)]. APRI and FIB-4 were strongly correlated (r = 0.78, P < 0.001, R² = 0.61). Overall median APRI scores were low {HIV/HBV [0.36 (interquartile range 0.4)], HIV [0.23 (0.17)], HBV [0.29 (0.15)] (P < 0.01)}. In multivariate analyses, HIV/HBV coinfection was associated with APRI >0.5 [HIV/HBV vs. HIV: odds ratio (OR) 3.78 (95% confidence interval: 1.91 to 7.50)], [HIV/HBV vs. HBV: OR 2.61 (1.26 to 5.44)]. HIV RNA per 1 log₁₀ copies/mL increase [OR 1.53 (95% confidence interval: 1.04 to 2.26)] and HBV DNA per 1 log₁₀ copies/mL increase [OR 1.36 (1.15, 1.62)] were independently associated with APRI >0.5 in HIV-infected and HBV-infected patients, respectively.

Conclusions: 

HIV/HBV coinfection is an important risk factor for significant fibrosis. Higher levels of circulating HIV and HBV virus may play a direct role in liver fibrogenesis. Prompt diagnosis and aggressive monitoring of liver disease in HIV/HBV coinfection is warranted.

INTRODUCTION

Chronic hepatitis B virus (HBV) infection is a major global health problem infecting over 240 million people worldwide and causing >600,000 annual deaths.¹ In Tanzania, 6%–7% of the population is coinfected with HIV and HBV.² In patients with chronic HBV, HIV significantly accelerates liver disease and leads to higher rates of liver complications.³ Few studies have examined rates of liver fibrosis in patients infected with chronic HBV alone and compared those to HIV/HBV-coinfected persons to determine the impact of HIV coinfection on liver outcomes. Evaluating liver fibrosis in patients with chronic HBV with and without HIV is crucial for assessing long-term prognosis and, in HBV monoinfected patients, determining the need for antiviral therapy. It is particularly important in sub-Saharan Africa (SSA) where HBV is endemic and additional risks of liver injury exist.⁴ In the United States, liver biopsy, transient elastography (TE, FibroScan; Echosens, Paris, France), and serologic testing, such as FibroSure are commonly used to determine the degree of fibrosis in patients with chronic HBV; however, these tests are rarely available in SSA. Aspartate aminotransferase (AST)-to-platelet ratio index (APRI) and fibrosis 4 (FIB-4) are 2 inexpensive, noninvasive and nonproprietary serum markers of fibrosis that are recommended by World Health Organization (WHO) for assessing liver fibrosis in low- and middle-income countries¹ when more expensive measures are not available.

We used APRI and FIB-4 to compare the prevalence of liver fibrosis in treatment-naive HIV, HBV, and HIV/HBV-coinfected individuals in Dar es Salaam, Tanzania. The goal of our study was to improve the current gap in understanding of liver disease associated with HBV and HIV in a setting where a high burden of both infections exists.

METHODS

Study Design, Site, and Population

This cross-sectional study was conducted among adult (age ≥18 years) patients enrolled in 8 HIV care and treatment clinics (CTCs) and a single HBV clinic in Dar es Salaam, Tanzania (HIV prevalence ≈ 4.7% in 2015⁵), which are supported by Management and Development for Health (MDH) under the President's Emergency Plan For AIDS Relief (PEPFAR). Antiviral therapy naive, HIV-infected, HBV-infected, and HIV/HBV-coinfected adults evaluated between April 2014 and November 2015 were considered eligible for enrollment. Patients with active tuberculosis or who were pregnant, anti-HCV seropositive, or had a known history of hepatocellular carcinoma or clinical evidence of advanced liver disease (jaundice, hepatic encephalopathy, ascites, and abnormal bleeding) were excluded. Chronic hepatitis B was defined as HBsAg seropositive on at least 1 occasion within the last 6 months. Patients were recruited for participation and enrolled in MDH-supported CTCs following written informed consent, which was subject to ethical reviews by the National Institution of Medical Research, Dar es Salaam, Tanzania, and Northwestern University.

Study Procedures

HIV-infected patients receive free access to antiretroviral treatment, monthly clinical visits, and semiannual virological monitoring according to Tanzanian National HIV Guidelines.⁵ HBV monoinfected patients are evaluated monthly and receive free access to lamivudine, which is initiated in all patients. Laboratory tests performed for the study included CD4⁺ T-cell count, HIV RNA quantification [Cobas Amplicor HIV-1 monitor test v2.0; lower limit of detection <20 copies/mL; Roche Diagnostics Corp., Indianapolis, IN], platelets, AST, alanine aminotransferase, creatinine, HBeAg/anti-HBe (EIA assay Cobas e411), and HBV DNA (COBAS Ampliprep Taqman 96, v2.0; lower limit of detection <20 IU/mL; Roche Diagnostics GmbH, Mannheim, Germany). All laboratory tests were conducted at the MDH-supported Temeke Research Laboratory. Demographic, clinical, laboratory, and therapeutic data were collected on National Care and Treatment Center forms (CTC 2) and supplementary forms which are entered into a secure computerized database. Alcohol consumption was defined as “yes” or “no” in a response to a question asking about current alcohol use. Daily alcohol consumption was also quantified, but these data were not included because the numbers were too small for any meaningful analyses.

Assessment of Liver Fibrosis

APRI and FIB-4 were calculated using standard definitions: APRI (AST/ULN × 100)/platelet count 10⁹/L, FIB-4 [age (years) × AST (IU/L)]/[platelet count (10⁹/L) × alanine aminotransferase (IU/L)^1/2].^6,7 Cutoff values of 0.5 and 1.45 were used for APRI and FIB-4, respectively. These are the lower cutoffs proposed by the WHO for significant fibrosis (METAVIIR >F2), which have a high sensitivity for ruling out F2 and above. We also conducted our analyses using the higher APRI cutoffs for significant fibrosis 1.5 and 3.25, which at this higher level are more specific for the diagnosis of fibrosis.¹ Results using APRI >0.5 are presented given the low prevalence of APRI scores >1.5 in our cohort.

Statistical Analysis

Univariate and multivariate (MV) logistic regression analyses were used to examine the association between APRI, FIB-4 (primary outcomes), and HBV coinfection as well as other HIV and HBV factors. In MV analyses, covariates were identified through stepwise regression and retained if their P value was < 0.20. P values < 0.05 were considered statistically significant. All the analyses were repeated using higher APRI (≥1.5) and FIB-4 (>3.25) cutoffs, respectively. Concordance between baseline APRI and FIB-4 values was assessed using Pearson correlation coefficient. All statistical analyses were performed using SPSS, v22.0; IBM, Armonk, NY.

RESULTS

Baseline Characteristics

All 267 HIV monoinfected (Table 1), 63/68 HIV/HBV-coinfected, and 165/168 HBV monoinfected patients who were enrolled in the study were included in the final analysis {median age 37 years [interquartile range (IQR) 14], median body mass index 23 (IQR 7.0), 44% men}. The 5 HIV/HBV- and 3 HBV-infected patients were excluded because complete HBV virologic and HBeAg/anti-HBe serologic testing revealed no evidence of chronic HBV infection. HBV monoinfected patients were more likely to be men [67% (HBV) vs. 48% (HIV/HBV) and 29% (HIV)], younger [32 years (HBV) vs. 37 (HIV/HBV) and 39 (HIV)] and have a higher median body mass index [25 (IQR 7) (HBV) vs. 21 (6.4) (HIV/HBV) and 22 (6.6) (HIV)]. HIV/HBV-coinfected patients were significantly more likely to be HBeAg seroreactive (37% vs. 10%) and have HBV DNA ≥4.3 log IU/mL (37% vs. 16%) than HBV monoinfected patients. Overall, median APRI scores were 0.27 (IQR 0.19). Eighty percentage of the study population had APRI and FIB-4 scores <0.5 and <1.45, respectively, scores which are indicative of minimal fibrosis if any. Median APRI scores were similar between HIV [0.23 (IQR 0.17)] and HBV monoinfected patients [0.29 (0.15)], but significantly lower than HIV/HBV-coinfected patients [0.36 (0.4)] [P values for pairwise comparisons <0.01 (vs. HIV) and 0.07 (vs. HBV), respectively].

TABLE 1.: Baseline Characteristics of the Study Population

Risk Factors Associated With Advanced Fibrosis

HIV/HBV coinfection was significantly associated with APRI >0.5 compared with HIV (P < 0.01) and HBV monoinfection (P = 0.01) in MV analyses (Table 2). In a subgroup analysis of patients with HIV, both HIV RNA per 1 log₁₀ copies/mL increase [odds ratio (OR) 1.53 (95% confidence interval: 1.04 to 2.26); P = 0.04] and HBV coinfection [OR 4.29 (1.98, 9.31); P < 0.01] were independently associated with APRI >0.5, whereas CD4⁺ T-cell count, WHO stage, age, and sex were not. In patients with HBV, coinfection with HIV [OR 2.64 (1.30, 5.34); P < 0.01], HBeAg seroreactivity [3.50 (95% confidence interval: 1.60 to 7.67); P < 0.01] and HBV DNA levels per log₁₀ IU/mL [OR 1.36 (1.15, 1.62); P < 0.01] were all associated with APRI >0.5 in univariate analyses. The magnitude of association between coinfection with HIV and APRI >0.5 fell to nonsignificant levels (P > 0.05) after adjusting for HBV DNA and HBeAg status (examined independently because of the high degree of collinearity between these variables) in MV models.

TABLE 2.: Factors Associated With Significant Liver Fibrosis (APRI >0.5), All Patients

Similar results were observed when repeating all the above analyses using the higher APRI cutoff ≥1.5 and the high and low FIB-4 significant fibrosis categories recommended by WHO (≥1.45 and ≥3.25) (data not shown).¹ Both APRI and FIB-4 were highly correlated (r = 0.78, P ≤ 0.001, R² = 0.61). HBV DNA was not predictive of FIB-4 ≥1.45 in HBV-infected patients, presumably because of the slightly lower number of HBV-infected patients in the higher FIB-4 vs. APRI fibrosis categories.

DISCUSSION

We present one of the largest studies to date from SSA comparing the prevalence of liver fibrosis using APRI and FIB-4 in treatment-naive, HIV-, HBV-, and HIV/HBV-infected patients. The use of noninvasive markers, APRI and FIB-4, was feasible in this setting, and both were highly correlated. Overall, the prevalence of significant liver fibrosis in HIV- and HIV/HBV-coinfected patients in this study was much lower than that reported in a recent study from Tanzania using an APRI cutoff ≥1.5 (9.1% and 14.2%, respectively).⁸ Patients in our cohort reported significantly less alcohol consumption (7.9% vs. 25.2%), had lower median AST levels (25.9 vs. 53 IU/mL), and a higher median CD4⁺ cell count (212 vs. 185 cells/mm³), which we speculate may have contributed to the differences in APRI score observed between the 2 studies. In addition, we also excluded patients with active tuberculosis.

A significantly higher rate of fibrosis was observed in patients with HIV/HBV coinfection compared with HIV and HBV monoinfection, confirming findings from several other SSA studies.^4,8,9 Notably, HIV/HBV-coinfected patients had almost 3 times the risk of APRI >0.5 compared with patients with HBV alone. In MV analyses of HBV-infected patients, HBeAg seroreactivity and HBV DNA levels ≥4.3 log₁₀ IU/mL explained about 50%–70% of the increased risk of fibrosis because of coinfection with HIV (data not shown). Our findings confirm a relationship between the level of active HBV viral replication and the risk of liver disease progression, which has been observed in other studies.¹⁰

HIV-infected patients had a similar prevalence of fibrosis compared with patients with HBV. The presence of liver fibrosis in HIV-infected patients without viral coinfection has been well documented. In Uganda, HIV infection was associated with a 50% increased odds of liver stiffness measurement by TE compared with HIV-uninfected individuals.⁴ Similar findings have been observed in the United States.¹¹ Several mechanisms underlying the association between HIV and liver fibrosis have been proposed.¹² The strong association between HIV VL and APRI >0.5 in both HIV- and HIV/HBV-infected patients who was seen in this study suggests an effect of HIV itself on the liver.

This study provides some of the first data characterizing HBV infection and liver disease risk in HBV monoinfected populations in Tanzania. Most HBV monoinfected patients were HBeAg seronegative and had low levels of HBV DNA. Furthermore, less than 5% had evidence of advanced liver disease. Similar to other SSA studies,⁹ a higher prevalence of significant fibrosis was observed in patients who were HBeAg seropositive and in patients with high HBV DNA (data not shown). Our data suggest that most HBV monoinfected patients in this setting are likely to be at very low risk of liver disease progression; however, this needs to be confirmed in longitudinal studies.

Strengths of our study include the large number of patients evaluated and inclusion of an HBV monoinfected population recruited from the same community. Although APRI and FIB-4 may be less sensitive for the detection of fibrosis and cirrhosis compared with other measures such as TE,¹³ our data are consistent with other studies of liver fibrosis in HIV- and HBV-infected populations in SSA, where more expensive fibrosis measures have been used.^9,14 Thus, findings in our study would support the use of APRI and FIB-4 in these settings. In addition, there is less concern now about the sensitivity of these measures in HIV/HBV-coinfected patients, most of who receive antiviral therapy regardless of any specific HBV treatment criteria. One important potential limitation was the lack of data on important confounders, such as the use of hepatotoxic medications, recreational drugs, and coinfection with HDV. In a recent study from Tanzania, no confirmed cases of HDV infection in over 200 HIV/HBV-coinfected patients were observed.¹⁵

In conclusion, in this large study of treatment-naive Tanzanian HIV-, HBV-, and HIV/HBV-infected adults, coinfection with HIV/HBV was associated with a significantly higher risk of liver fibrosis than either infection alone. The utility of inexpensive fibrosis markers, such as FIB-4 and APRI in this setting, was demonstrated. This study highlights the importance of screening all HIV-infected patients for HBV and early initiation of HBV active antiretroviral therapies in these individuals.