Predictors of liver disease outcomes in individuals with hemophilia and HCV infection

Hemophilia is an X-linked bleeding disorder caused by defective or deficient coagulation factor VIII or IX and is characterized by spontaneous and traumatic bleeding. Although clotting factor concentrate replacement several times weekly is effective in preventing bleeds, it was complicated by hepatitis C virus (HCV) infection in >90%, some of whom have progressed to cirrhosis and end-stage liver disease (ESLD).^1-4 Many coinfected with HIV have experienced accelerated liver disease progression,^5,6 which despite antiretroviral therapy,⁷ has resulted in biopsy-proven fibrosis in 25% after 25 years of coinfection,⁶ some of whom required liver transplantation.^8,9 Although HCV antiviral therapy effectively clears HCV infection, it does not prevent the development of hepatocellular cancer (HCC),¹⁰ which is increasing in those with hemophilia^11,12 and is now recognized as the fastest-rising cancer-related cause of death in the United States.¹³ The major risk factor for HCC is cirrhosis due to viral hepatitis C and the increasingly recognized nonalcoholic fatty liver disease,^13,14 not only in the general population but also in those with hemophilia,⁴ among whom liver disease remains the leading cause of death.¹⁵ 

In the United States, at least half of the increase in HCC cases occurs in the aging cohort with HCV infection. However, in contrast to the general population, men with hemophilia acquire HCV infection early in life, with their first factor infusion typically in the first year of life,¹⁶ and thus have among the longest duration HCV infection of all those at risk,⁶ and increasing risk for ESLD and HCC as they age. Despite this, the sequelae of chronic HCV infection, now >50 years after the initial exposure has not been well described or studied.^17-19 We, therefore, sought to determine the current incidence and risk factors for ESLD and HCC in a well-characterized cohort of men with hemophilia and chronic longstanding HCV infection.

This was a retrospective cohort study of 121 men with HCV and hemophilia cared for at the Hemophilia Center of Western Pennsylvania, whose medical outpatient charts were reviewed under the University of Pittsburgh Institutional Review Board exempt determination (#21100086). HCV outcomes, including ESLD, HCC, platelet count <100 000/μL, and mortality, were analyzed by ethnicity, HIV status, hemophilia type, inhibitor status, and antiviral therapy. ESLD was a clinical diagnosis, based on the occurrence of several symptoms and signs including thrombocytopenia, gastrointestinal bleeding, esophageal varices, ascites, edema, and encephalopathy. Laboratory draw frequency was during comprehensive care clinics, every 1 to 2 years. Patients with HIV who were alive when antiretroviral therapy became available were offered it, and all who were treated achieved controlled HIV infection (negative HIV viral load); 1 patient refused treatment and remained uncontrolled. We estimated the incidence rate of pathologically confirmed HCC in patients with hemophilia and HCV by race, HIV status, inhibitor status, antiviral therapy, and ESLD. Liver biopsies prospectively performed on 32 patients (26.4%) as part of the Impact of HIV on Hepatitis C in Hemophilia Study,⁶ were scored by the Knodell,²⁰ Ishak,²¹ and Metavir²² classification systems, with Ishak fibrosis 0 to 6 and Metavir fibrosis F0 to F4. Age and causes of death were known in mortality reports and were collected as part of comprehensive care. Predictors of ESLD and HCC were evaluated using odds ratios (ORs) and 95% confidence intervals (CIs), and significance was determined using Fisher exact test for discrete variables and univariable logistic regression for continuous variables. HCV-associated outcomes were evaluated using Kaplan-Meier time-to-event analyses and compared between the groups using log-rank tests. Univariable Cox proportional hazard models were fitted to estimate hazard ratios (HRs) and 95% CIs. Given the relatively small sample sizes and low outcome rates, we were unable to perform multivariable modeling because the models would be overfitted. A P value of <.05 was considered statistically significant with no adjustment made for multiplicity. All analyses were completed in R version 3.6.2.

Of 121 patients in this cohort, 95 (78.5%) had hemophilia A and 26 (21.6%) had hemophilia B, of whom 13 (10.7%) had a current or historic inhibitor (Table 1). The mean age was 54 years (range, 36-80). By race, 115 (95.0%) were White, and 31 (25.6%) were HIV⁺. Antiviral treatment for HCV in 46 patients (38.0%) included direct-acting antiviral agents in 31 (67.4%) and interferon and/or ribavirin in 15 (32.6%); of those untreated, most died before its availability. At a mean 54 years duration of HCV infection, ESLD developed in 24 (19.8%) or 0.365 per 100 person-years (py); platelets <100 000/μL in 9 of 93 (9.7%) or 0.173 per 100 py, and HCC in 7 (5.8%) or 0.106 per 100 py. It should be noted that, as the age at initial HCV exposure was within the first year of life, the current age (or age at death) of the cohort was also the duration of chronic HCV infection.

A total of 34 (28.1%) patients in the cohort had died by the time of this analysis, with an HCV-associated mortality incidence rate of 0.335 per 100 py. ESLD was the most common cause of death, occurring in 11 (32.3%), followed by bleeding in 9 (26.5%), HCC in 6 (17.6%), and AIDS, Parkinson disease, IV drug use, pancreatic cancer, and suicide in 1 (2.9%) each.

Significant risk factors for ESLD included platelets <100 000/μL (OR, 6.009; 95% CI, 1.283-23.741; P = .012) and HIV infection (OR, 3.883; 95% CI, 1.602-9.596; P = .001; Table 2). No antiviral-treated patient developed ESLD (P = .001). The presence of ESLD was the most significant predictor of HCC (OR, 11.476; 95% CI, 1.876- 120.754; P = .003), and the second most significant predictor was platelets <100 000/μL (OR, 6.159; 95% CI, 1.219-28.712; P = .014). The Knodell score per unit score increase was a significant predictor of HCC (OR, 2.453; 95% CI, 1.239-7.903; P = .044), whereas the Ishak score, per unit score increase, was a significant predictor of ESLD (OR, 1.933; 95% CI, 1.156-4.031; P = .032). Metavir scores were not predictive of ESLD or HCC, and none of the histologic scores were predictive of HCV-associated mortality.

Kaplan-Meier survival curves for HCV-associated mortality by ESLD, HIV, antiviral treatment, and HCC are shown in Figure 1. HRs for the predictors of mortality are shown in Table 3. The overall mean ± standard error of the mean survival from the initial HCV infection was 8890 ± 240 days (24.3 years). Among those with ESLD, the mean overall survival was 5321 ± 649 days (14.5 years) vs 9773 ± 152 days (26.8 years) in non-ESLD (P < .001); (HR, 3.074; 95% CI, 1.51-6.257; P < .001). In HIV⁺ patients, the mean survival was 7032 ± 676 days (19.3 years) vs 9530 ± 178 days (26.1 years) in HIV^– patients (P = .001) (HR, 3.074; 95% CI, 5.137-22.49; P = .002). The mean survival among antiviral-treated was 10 210 ± 19 days (28.0 years) vs 8094 ± 365 days (22.2 years) in untreated (P = .001); (HR, 10.75; 95% CI, 0.149-0.701; P = .004); and in those with HCC, the mean survival was 8433 ± 614 days (23.1 years) vs 8918 ± 251 days (24.4 years) in those with no HCC (P = .027); (HR, 2.622; 95% CI, 1.08-6.365; P = .033).

The overall cumulative incidence of ESLD at 54 years of mean duration of HCV infection was 16.9% or 0.365 per 100 py. Among HIV⁺ men, ESLD occurred in 41.4% vs 7.4% of HIV^– men (P < .001); among HCV viral-untreated men, ESLD occurred in 27.1% vs 0.0% of antiviral-treated men (P < .001); and among those with platelets <100 000/μL, ESLD occurred in 48.1% vs 1.6% of those with platelets ≥100 000/μL (P < .001).

The overall cumulative incidence of HCC was 2.88% or 0.106 per 100 py. Among those with ESLD, HCC occurred in 6.67% vs 2.04% of patients without ESLD (P < .001). Among those with platelets <100 000/μL, HCC occurred in 33.3% vs 1.6% of those with platelets ≥100 000/μL (P < .001).

In individuals with hemophilia and chronic HCV infection, our study found that ESLD is common, affecting nearly a quarter of HCV-infected men with hemophilia, and remains a major risk for HCC, as previously recognized.^4,12 Remarkably, after 54 years of mean duration of HCV infection, the cumulative incidence of ESLD in this cohort of men with hemophilia, 0.365 per 100 py, is ∼4.7-fold higher than in US veterans, 0.078 per 100 py²³; and the cumulative incidence of HCC in this cohort, 0.106 per 100 py, is 15.8-fold higher than in the US Cancer Statistics Registry.²³ The disproportionately higher incidence of ESLD in men with hemophilia than in US veterans likely reflects the higher rates of HCV and HIV in men with hemophilia, which are known risk factors for ESLD. It is of note that HIV infection in men with hemophilia has also been associated with higher hypertension and diabetes risks in the hemophilia population as compared with the general adult population.²⁴ 

ESLD is also the leading cause of death, consistent with past⁶ and more recent studies.¹⁵ Despite improvement in antiviral efficacy in chronic HCV, HCC is not declining even with antiviral therapy overall¹⁰ and, in particular, in those with hemophilia, consistent with recent studies.^11,12 Our data also confirm HIV infection remains a critical predictor of ESLD, but because of the success of antiretroviral therapy, all patients treated with antiretroviral therapy achieved HIV control, an uncommon cause of death.

The most powerful predictor of ESLD identified in this cohort of patients with hemophilia and HCV infection was thrombocytopenia, specifically a platelet count <100 000/μL. This is not surprising, given that splenic sequestration of platelets commonly occurs in those with fibrosis or cirrhosis. However, as fibrosis and early cirrhosis may be asymptomatic, and noninvasive imaging and liver biopsies may not be routinely performed to monitor liver disease progression in this population, platelet count might be a simple and useful marker to follow. Yet, although thrombocytopenia was a predictor of ESLD, it was surprisingly not a predictor of HCC, which typically occurs in the setting of fibrosis or cirrhosis.^25,26 This may suggest that platelet count performed annually for hemophilia center visits may be too infrequent to predict HCC, or alternately, even though platelet counts may indicate early splenic sequestration and portal hypertension, they may not be as predictive of HCC as advanced fibrosis or cirrhosis.

Whether thrombocytopenia is associated with clinical bleeding is not known separately from the typical causes of bleeding in hemophilia, for example, hemarthrosis and hematomas. Importantly, there was no increase in central nervous system bleeding, as previously seen in those with HIV-associated idiopathic thrombocytopenic purpura, whose platelet counts were significantly lower than those associated with ESLD and portal hypertension in this group.²⁷ However, it is important to note in this study that although platelet counts were obtained at least every 1 to 2 years for routine hemophilia clinic, the infrequency of these data interferes with specific cause and effect assessment.

Finally, the finding that ESLD has occurred in nearly 20% of this hemophilic cohort after 54 years duration of HCV infection is consistent with the increase in liver disease progression with increasing duration of HCV infection in the general HCV⁺ population. Among those with hemophilia, since their first exposure to HCV was with the first blood product exposure,¹⁶ typically in the first year of life, they had the longest duration of HCV infection and among the highest rates of ESLD in those with HCV infection.

There are several limitations of this study. First, this was a retrospective study dependent on a review of charts that were not originally designed for research, for which some information may be missing. Second, this was a small cohort, limiting the generalizability of the findings and the potential to perform multivariable analyses or compare survivors with those who died before HCV antiviral therapy. Third, another limitation was the lack of a control cohort. However, ESLD and HCC incidence in roughly age-matched male populations were able to be included for comparison.²³ Fourth, the timing of data collection was variable, which may limit the assessment of risk factors and outcomes, such as the lag time from the onset of thrombocytopenia to ESLD. Fifth, neither routine ultrasound, biopsies, nor biomarkers for ESLD or nonalcoholic fatty liver disease were routinely assessed in this group, nor were body mass index, alcohol, or other lifestyle characteristics, limiting precision in measuring liver disease outcomes. Despite this, the study strengths include a cohort in which all outcomes were known and in which at least 1 subset had liver biopsies, the gold standard for fibrosis detection.

In summary, we described the sequelae of chronic HCV infection in a cohort of HCV-infected patients with hemophilia >50 years after the initial HCV exposure. These findings are particularly important for future health care planning as this population ages and suggest the importance of routine assessment of liver function and liver disease surveillance per the American Association for the Study of Liver Disease, the American Gastroenterological Association, and the Medical and Scientific Advisory Council of the National Bleeding Disorders Foundation.^17-19 

This study was supported by the Pennsylvania Department of Health Support of Hemophilia Center of Western Pennsylvania, standard operating procedure #410000797, and Federal Hemophilia Treatment Center Health Resources and Services Administration grant H30MC24050-04-00.

Contribution: M.V.R. contributed to data acquisition; I.C. and S.R. performed the data analysis; and all authors contributed to the study design, interpretation of the data, writing of the manuscript, and performed a critical review of and approved the final manuscript.

Conflict-of-interest disclosure: M.V.R. has received research funding to her institution from BioMarin, Sanofi, Spark Therapeutics, and Takeda, and has served on advisory boards of bebio, BioMarin, HEMA Biologics, Sanofi, Spark Therapeutics, and Takeda. The remaining authors declare no competing financial interests.

Correspondence: Margaret V. Ragni, Division Classical Hematology, University of Pittsburgh Medical Center, c/o Hemophilia Center of Western Pennsylvania, 201 N. Craig St, Suite 500, Pittsburgh, PA 15213; email: ragni@pitt.edu.