The effect of anemia on the efficacy and safety of treating chronic hepatitis C infection with direct‑acting antivirals in patients with chronic kidney disease

Ahmed Yahia Elmowafy1 · Mohamed Hamed Abbas1 · Ahmed Abdelfattah Denewar1 · Mohamed Elsayed Mashaly1 · Gamal Shiha2 · Salwa Mahmoud El Wasif1 · Lionel Rostaing3,4 · Mohamed Adel Bakr1

Abstract

Background/Aim Chronic hepatitis-C infection is a great health burden in Egypt. The effect of anemia on the efficacy and safety of direct-acting anti-viral (DAA) therapies for those with chronic-kidney disease (CKD) has not been evaluated.
Patients/Methods This single-center retrospective study included 235 renal patients: i.e., 70-CKD patients not on hemo- dialysis (42 with anemia, 28 without); 40 hemodialysis patients (16 anemic; 24 non-anemic), and 125 kidney-transplant (KTx) recipients (40 anemic; 85 non-anemic). Anemia was defined by a hemoglobin level < 10.5 g/dL. Hemodialysis patients received ritonavir-boosted paritaprevir/ombitasvir. KTx patients received sofosbuvir/daclatasvir. CKD patients with eGFR > 30 mL/min/1.73 m2 received sofosbuvir/daclatasvir. Those with eGFR < 30 mL/min/1.73 m2 received ritonavir- boosted paritaprevir/ombitasvir; 64 non-anemic patients also received ribavirin therapy.
Results Mean age of CKDs was 49.1 years, 43.2 years for HDs, and 45.2 years for KTx patients. Most were male; body-
mass index was ~ 23.8. Anemia did not affect the efficacy of DAAs in hemodialysis, CKD, or KTx patients. Most patients achieved a rapid virologic response (RVR), and a 12- and 24-week sustained viral response. Worsening of anemia among the non-anemic group was mostly related to ribavirin therapy in hemodialysis patients (11/16 patients). Acute kidney injury in CKDs occurred more frequently within the anemic group (59.5%) compared to the non-anemic group (32.1%). For KTx, graft impairment was more common among the anemic group (7/40) compared to the non-anemic group (2/85).
Conclusion Hemoglobin levels of < 10.5 g/dL prior to DAA treatment did not affect the virological response in renal patients but was associated with increased serum creatinine among KTx and those with CKD.

Keywords Chronic kidney disease · HCV infection · Sofosbuvir · Daclatasvir · Anemia · Kidney transplantation · Hemodialysis · DAA therapy

Introduction

Hepatitis C virus (HCV) infection is strongly associated with chronic kidney disease (CKD), an independent risk factor for developing CKD. HCV significantly increases morbidity and mortality in patients with CKD [1]. In addition, HCV may accelerate the progressive loss of kidney function and is associated with a more than two-fold risk of developing end-stage renal disease (ESRD) [2]. Moreover, chronic HCV infection increases the mortality rates of dialysis patients [3]. HCV sero-positivity is also associated with a higher risk of mortality in kidney-transplant recipients (KTx), [4].
Treating patients with HCV and severely impaired renal function can be challenging. There is a risk of increased exposure to drugs that undergo significant renal elimination. Patients that require dialysis can be additionally affected by drug exposure and clearance [5]. Sofosbuvir, the foundation of many current direct-act- ing antivirals (DAA), is not recommended for patients that have CKD stage 4 or those with ESRD due to the ~ 20-fold increased exposure to the sofosbuvir metabolite, GS-331007, which is renally eliminated [6]. Instead, the American Asso- ciation for the Study of Liver Disease (AASLD)/Infectious Diseases Society of America (IDSA) currently recommends 12 weeks of treatment with elbasvir/grazoprevir (HCV geno- type (GT) 1a, GT1b or GT4) or 8–16-week treatment with glecaprevir/pibrentasvir (GT1–6) [7].
The combination of three DAAs: i.e., ombitasvir (an NS5A inhibitor), ritonavir-boosted paritaprevir (an NS3/4A serine protease inhibitor), and dasabuvir (an NS5B non- nucleoside polymerase inhibitor), administered with and without ribavirin, is another treatment option for patients with HCV genotype 1 (GT1) or GT4 infection, including those with mild, moderate, or severe renal impairment and those on dialysis [8].
Patients with ESRD can develop progressive anemia due to low endogenous erythropoietin (EPO) production by the kidneys. Fortunately, therapy with exogenous EPO can pre- vent/treat debilitating anemia, aiming at hemoglobin (Hb) levels between 10 and 11.5 g/dL. Those with low (< 10 g/ dL) and high hemoglobin levels (> 11.5 g/dL) are associated with increased cardiovascular events and death [9].
Anemia is also a commonly observed complication in patients treated for HCV, especially with a ribavirin regi- men: drug discontinuation or dose modification is then rec- ommended [10]. The aim of our single-center study was to assess whether the management of anemia in CKD patients affected the efficacy and safety of the DAAs used to treat chronic HCV infections.

Patients and methods

Study design and setting

This single-center, retrospective, cohort study was con- ducted in the Urology and Nephrology Center, Mansoura University, Egypt.

Participants and eligibility criteria

All the HCV RNA-positive hemodialysis and HCV RNA- positive kidney transplant patients in our center were included in our study: they all received direct-acting anti- viral between 2016 to 2019. In addition, HCV RNA(+) CKD patients followed-up at our outpatient clinic from 2016 to 2019 and who received DAAs were also included.
All available patients were included to avoid selection bias. The sample size was calculated using prevalence of anemia among CKD patients reported by Ryu et al. [11] using G. power program with α. Error = 0.05 and power 80% then the calculated sample size is approximately 235 patients (see Tables 1, 2, 3).
• Group I: 70 patients with CKD (not yet on hemodialy- sis).
• Group II: 40 hemodialysis (HD) patients.
• Group III: 125 KTx patients.
All patients received direct-acting anti-virals (DAAs) with or without ribavirin to treat chronic HCV infection.
Each group was subdivided into two subgroups accord- ing to hemoglobin level prior to starting anti-HCV treat- ment. Even though anemia related to CKD is diagnosed when hemoglobin level is < 11 g/dL because erythropoietin therapy is only reimbursed in Egypt if Hb level is < 10.5 g/ dL we decided (for our study) to choose a hemoglobin level of < 10.5 g/dL as the cut-off value for anemia. The anemic groups had Hb levels of < 10.5 g/dL and the non-anemic groups had Hb levels ≥ 10.5 g/dL. Thus, the prevalence of anemia was 60%, 40%, and 32% in CKD, HD, and KTx patients, respectively.

Before treatment

All patients underwent a clinical examination, laboratory investigations [serum creatinine, estimated glomerular-filtra- tion rate (eGFR) according to the MDRD formula, hepatic transaminase levels, i.e., aspartate (AST) and alanine (ALT) aminotransferases, bilirubin, albuminemia, total cholesterol, prothrombin time, complete blood counts, immunosuppres- sive-drug trough levels for KTx patients, and HCV RNA viral load] and radiological assessment (a liver ultrasound and a fibroscan). All patient’s maintenance medications were revised for drug interactions with DAAs using the Liverpool HEP drug checker website (https://www.hep-druginteraction s.org/). Diagnosis of the severity of cirrhosis was based on the Child–Pugh score, which depends on the presence of hepatic encephalopathy, ascites, the level of bilirubin and albumin, and prothrombin time [12]. The degree of liver fibrosis was diagnosed based on the METAVIR score, using fibroscan [13].

Treatment details

Patients with CKD and an eGFR > 30 mL/min/1.73 m2 received a 3-month course of sofosbuvir (400 mg daily) and daclatasvir (60 mg daily). CKD patients with an eGFR < 30 mL/min/1.73 m2 received daily two tablets of ritonavir-boosted paritaprevir and ombitasvir (OMV/ PTV/RTV: 12.5 mg/75 mg/50 mg) for 3 months. Hemo- dialysis patients received a 3-month course of ritonavir- boosted paritaprevir and ombitasvir (two tablets daily of OMV/PTV/RTV: 12.5 mg/75 mg/50 mg). KTx recipients received a 6-month course of sofosbuvir (400 mg daily) and daclatasvir (60 mg daily). In addition, non-anemic CKD and HD patients (n = 44) and 20 non-anemic KTx received riba- virin therapy. Ribavirin dose for CKDs was 200 mg/day; hemodialysis patients received 200 mg/48 h; KTx recipients received 900–1200 mg/day. A rapid virological response was defined as viral clearance within 3 weeks of initiating treat- ment. A sustained virological response (SVR) was defined as viral clearance at 12 weeks after completing therapy. A relapse was defined as the reappearance of viral load after an initial recovery after treatment [14]. The follow-up period was 12 months after completing treatment.

Outcomes

They included (1) rapid virological response (RVR), i.e., viral clearance within 3 weeks of treatment initiation), (2) 12- and 24-week sustained virological response (SVR), i.e., persisting viral clearance at 12 and 24 weeks after com- pletion of DAA therapy, (3) ALT, AST, hemoglobin levels during and after DAA therapy, (4) hepatic decompensation during and after DAA therapy, (5) serum creatinine, eGFR, and proteinuria during and after DAA therapy for CKD and kidney-transplant patients, and (6) tacrolimus trough levels during and after DAA therapy for kidney-transplant patients.

Statistical analyses

All data were tabulated using an SPSS sheet. Descriptive measures were used for demographic and pre-treatment data. Repeat-measure ANOVA tests for parametric data and the Friedman test for non-parametric data were used to compare the laboratory findings before, during, and after treatment. The chi-square test was used to calculate the relative risk factors and the log-rank test was used to determine kidney survival among those with and without anemia, and with

Results

Baseline characteristics

Of our 235 renal patients, only 22 had previously received alpha-interferon (αIFN) (14 patients had a relapse after a primary response to αIFN and 8 did not tolerate α-IFN due to severe anemia, leucopenia, or recurrent infection). Seven patients had been co-infected with hepatitis B virus; how- ever, all patients were cleared of the virus prior to HCV treatment and were maintained life-long on Entecavir (0.5 mg/day). In addition, ten patients had cirrhosis; of which five were anemic.

Drug efficacy

All patients, with or without anemia, achieved an RVR (viral clearance within 3 weeks of treatment initiation).
For CKD patients, the 12- and 24-week SVRs were 94.3% and 77.1%, respectively, with no difference between anemic and non-anemic groups; there was no statistical difference across the two groups. Overall, there were 16 relapses, i.e., 22.8%. Four of the 16 patients (25%) had a relapse within 12 weeks after completing DAA treatment and 12 patients had a relapse beyond that time (75%). Eleven relapsers then received a 3-month ritonavir-boosted regimen and five cases received a 3-month sofosbuvir-based regimen. Five cases of relapse in the non-anemia group also received ribavi- rin, which was suspended after 1 month due to a drop in hemoglobin. The possibility that re-infection was related to hemodialysis-related nosocomial transmission occurred in three patients from group I, i.e., they had poor renal function during the first DAA treatment, and subsequently lost renal function and had to begin hemodialysis.
There was no statistical difference between the groups regarding hepatic transaminases either before treatment, during, or after completing DAA treatment. However, ALT levels significantly improved after treatment was completed: i.e., ALT levels before, during, and after in the non-anemic group were 49.5 ± 19.4, 41 ± 0.1, and 30 ± 16, respectively (p = 0.018); whereas ALT levels before, during, and after treatment in the anemic group were 41.8 ± 19.2, 35.1 ± 16.2, and 35.1 ± 16.2, respectively (p = 0.007).
For hemodialysis patients, the 12- and 24-SVRs were 100% and 95%, respectively, with one relapse in each group. Both cases received a 3-month ritonavir-boosted regimen. One case also received ribavirin (200 mg every other day) for 1 month, which was then suspended due to a drop in hemoglobin (10.8 g/dL before treatment to 8.8 g/dL after treatment). Both cases had a relapse by 3 months after completing treatment and had an initial response. There was no statistical difference between the two groups regard- ing baseline AST, bilirubin, or albumin. However, baseline ALT was significantly higher among the anemic group, i.e., 57.3 ± 23.9 IU/L compared to the non-anemic group, i.e., 36.1 ± 15.7 IU/L (p = 0.005). There was significant improve- ment in ALT in both groups: the anemic group had ALT levels before, at 1 month, and at 3 months after complet- ing treatment of 57.3 ± 23.9, 49.4 ± 22.3, 39.9 ± 19.8 IU/L, respectively (p = 0.009). The non-anemic group had ALT before, at 1 month, and at 3 months after complet- ing treatment of 36.1 ± 15.7, 29.6 ± 13.3, 24.4 ± 11.9 IU/L (p = 0.001).
All KTRs achieved an RVR and an SVR except for one patient (in the anemic group). Liver-enzyme levels were significantly improved in both groups: in the anemic group, ALT levels before, during, and after treatment were 50.3 ± 20.1, 38.2 ± 18.3, 35.7 ± 13.2 IU/L; p = 0.001; in non-anemic group, ALT levels before, during, and after treatment were 48.21 ± 19.8, 38.6 ± 17.9, 34.9 ± 12.9 IU/L; p = 0.001.
One patient had a relapse after receiving a 6-month sofosbu- vir-based regimen; relapse occurred 3 months after complet- ing treatment. He was not re-treated because he died from a cardiovascular event.

Drug tolerability

Overall, the drop in hemoglobin level was greater in the non-anemic group than the anemic group across the three types of patients. In addition, the drop in hemoglobin levels between, before and at 1 month after treatment was greater in the non-anemic group compared to the anemic group (i.e., CKD patients: 3.15 ± 0.1 vs. 0.4 ± 0.02 g/dL, respectively; 0.0001). CKD patients without anemia had hemoglobin lev- els before and at 1 month after starting DAA treatment of 11.52 ± 1.16, and 8.1 ± 1.06 g/dL, respectively (p = 0.0001). Hemodialysis patients without anemia had hemoglobin lev- els before and at 1 month after starting DAA treatment of 11.35 ± 0.63 and 9.2 ± 0.9 g/dL, respectively (p = 0.001. However, hemoglobin levels improved significantly in the non-anemic group after the 2nd month of treatment, mostly due to stopping ribavirin in 51 of 64 patients (79.7%). Hemo- globin levels at 1 month after starting and at 1 month after stopping ribavirin were as follows: CKD patients: 8.1 ± 1.06 vs. 8.88 ± 0.63 g/dL (p = 0.004); hemodialysis patients had 9.2 ± 0.9 vs.10.5 ± 0.44 g/dL (p = 0.0001); and KTx had 9.8 ± 0.9 vs.11.5 ± 1.23 g/dL, respectively (p = 0.0001).
Twenty KTx patients without anemia that received riba- virin had a significant drop in hemoglobin (11.8 ± 0.8 g/ dL at baseline vs. 8.06 ± 0.9 g/dL at 4 weeks after starting treatment; p = 0.001). As a consequence, we greatly reduced ribavirin dose, i.e., from 900 mg/day at the start of therapy to 200 mg/day at 1 month after initiating treatment. This ena- bled hemoglobin to increase to 10.4 ± 0.86 g/dL by 1 month later, i.e., during the 2nd month of DAA therapy.
An increase in serum creatinine among CKD, and KTx patients was a major side effect. Regarding CKD patients, baseline eGFR was less in those with anemia compared to those without anemia (26.7 ± 11.8 vs. 33.4 ± 16.2 mL/min; p = 0.04).
CKD patients had a deterioration in kidney func- tion within 1 month of starting DAAs; this was observed in 59.5% of anemic patients vs. 32.15% of non-anemic patients (p = 0.024). Thus, in the anemic group, eGFR was 26.7 ± 11.8 mL/min at baseline vs. 21.28 ± 13 mL/min at 1 month later (p = 0.014); in the non-anemic group, eGFR at baseline was 33.4 ± 16.2 vs. 29.2 ± 17.2 mL/min at 1 month later (p = 0.33). More of the anemic group (38.1%) needed hemodialysis, i.e., 16 (3 transient, 13 definitive) vs. 4 cases (14.3%; p = 0.03) in the non-anemic group (3 transient, 1 definitive). Figure 1 shows Kaplan–Meyer kidney-survival analysis among patients with CKD and with or without ane- mia (Tables 4, 5, 6).
Regarding KTx, graft impairment during treatment occurred more frequently amongst the anemic group, i.e., 7 of 40 KTx (17.5%) compared to 2 of 85 KTx (2.35%) in the non-anemic group (p = 0.004). Baseline eGFR was significantly lower in the anemic group vs. the non-anemic group (56.4 ± 12.3 mL/min vs. 63.9 ± 15.6; p = 0.008). Graft biopsies were performed in the nine patients that had deteriorating allograft function during DAA therapy. In the anemic group, three (7.5%) of the 40 KTx were diagnosed with acute rejection: three (7.5%) biopsies revealed acute tubular injury (ATI) with nega- tive C4d staining and no vasculitis, whereas, one patient’s (2.5%) biopsy revealed chronic transplant glomerulopa- thy. One (1.2%) of the 85 KTx in the non-anemic group experienced an acute rejection and one had ATI. Table 7 illustrates the details of the nine patients that experienced impaired graft function during DAA therapy.
Tacrolimus trough level at the time of acute-rejection epi- sodes was 4.3 ± 1.6 ng/mL and cyclosporine trough level was 94.4 ± 22.8 ng/mL. Acute-rejection episodes were treated with pulses of methylprednisolone (10 mg/kg for 5 days): responses varied from partial recovery (3 KTx) to complete recovery (1 KTx). The four cases of ATI responded well to good hydration and to lowering the tacrolimus trough-level to ~ 4 ng/mL. The case of chronic rejection was managed by increasing basal immunosuppression. We also observed that a sofosbuvir-based regimen did not affect immunosuppres- sive-drug trough levels (Table 7).
In a univariate analysis we analyzed the risk factors for developing a rise in serum creatinine during DAA therapy amongst patients with CKD or KTx patients (see Table 8). Only anemia was statistically associated as a risk factor (RR: 7.4, p value: 0.01).
Of the 235 patients, 14 (6%) (of which 10 already had cirrhosis) presented within 3 months after DAA therapy with hepatic decompensation (12 patients with anemia and 2 patients without anemia; p = 0.0016). Most cases (12 cases) occurred amongst those with CKD. Hepatic decompensation was diagnosed clinically by the development of ascites and lower-limb edema associated with a rise in liver enzymes and a decrease in serum-albumin levels. Hepatic decompen- sation was associated with a HCV RNA relapse in only three cases; two of these patients died.

Discussion

To the best of our knowledge, this is the first study to evalu- ate the effect of CKD -related anemia on the efficacy and safety of DAAs in a large cohort of HCV-positive CKD Egyptian patients. Our results show that (1) anemia did not affect the response to DAAs; (2) the addition of ribavirin therapy for non-anemic CKD patients caused a decline in eGFR estimated glomerular filtration rate according to MDRD formula; DAA direct-acting antiviral; OMV/PTV/RTV, Ombitasvir/Paritaprevir/ Ritonavir; RVR rapid virologic response; SVR sustained virologic response; AKI acute kidney injury; CKD chronic kidney disease; ESDR end- stage renal disease DAA direct-acting antivirals; RVR rapid virological response; SVR sustained virological response; OMV/ PTV/RTV Ombitasvir/Paritaprevir/Ritonavir and KTx patients developed impaired renal function more frequently than non-anemic CKD and KTx.
The prevalence of HCV infection remains higher in CKD and HD patients than in the general population (i.e., 5–10% in Europe and USA). In addition, in Egypt, the prevalence DAA direct antiviral agents; eGFR estimated glomerular filtration rate; ALT alanine aminotransferase; OMV/PTV/RTV Ombitasvir/Paritaprevir/Ritonavir of HCV infection in the general population is the world’s highest [15].
A variety of measures have reduced the prevalence of HCV infection in CKD patients [16]. Recently, the Dialysis Outcomes and Practice Patterns Study (DOPPS, 1996–2015) assessed trends in the prevalence, incidence, and risk factors for HCV infection, as defined by a documented diagnosis or antibody positivity in hemodialysis patients. They found that, among prevalent hemodialysis patients, the prevalence of HCV was nearly 10% in 2012–2015, ranging from 4% in Belgium to as high as 20% in the Middle East, with interme- diate prevalences in China, Japan, Italy, Spain, and Russia. However, the prevalence of HCV has decreased over time in most countries that have participated in more than one phase of DOPPS; its prevalence was ~ 5% among patients that had recently (< 4 months) initiated dialysis. The incidence of HCV infection has also decreased from 2.9 to 1.2 per 100 patient-years in countries participating in the initial phase of DOPPS.
CKD patients continue to experience unique challenges in HCV management, such as concerns about progressive liver disease and graft injury following renal transplanta- tion [17]. HCV often has a negative impact on the survival of post renal-transplant patients due to the increased risk of graft loss caused by chronic rejection and HCV-related de novo glomerulopathies, post-transplant diabetes, de novo cancer, including hepatocarcinoma, and the rapid progres- sion of liver fibrosis [18–20]. The advent of a well-tolerated oral regimens for HCV infection has expanded treatment options for patients with severe CKD and HD. Although ribavirin was envisioned to become obsolete with the advent of DAAs, it continues to play an adjunct role in some regi- mens, particularly in real-life settings in Egypt [21].
Until recently, data for the use of oral regimens given to patients with severe CKD or on dialysis have been limited. This is reflected in the HCV guidelines, which formerly endorsed the use of initially available DAA regimens only for patients with a GFR of > 30 mL/min, which clearly pre- cluded HD patients from therapy [22]. Among the currently approved DAAs, sofosbuvir, an NS5B polymerase inhibitor, is the only DAA that is renally eliminated. Therefore, there is no recommended dose for sofosbuvir in cases of severe renal insufficiency or for those on dialysis. A few pharma- cokinetic and clinical data report on the use of sofosbuvir in the setting of HD [23, 24]. Desnoyer et al. reported on a multicenter, prospective, and observational study of HD patients that received sofosbuvir [400 mg once daily (n = 7) or 3 times a week (n = 5)], after hemodialysis with sime- previr, daclatasvir, ledipasvir, or ribavirin. They reported that plasma concentrations of sofosbuvir or its inactive metabolite GS-331007 did not accumulate within hemo- dialysis sessions or throughout the treatment course [25]. The other currently approved DAAs (simeprevir, ledipas- vir, daclatasvir, paritaprevir/ritonavir, ombitasvir, dasabuvir, grazoprevir, and elbasvir) are not eliminated renally and thus do not need dose adjustment in cases of severe CKD or in a HD setting [25].
In Egypt, for KTX, HD, and CKD HCV genotype 4-infected patients, we recently reported on the efficacy of a sofosbuvir-based regimen if eGFR was > 30 mL/min or with a ritonavir-boosted paritaprevir/ombitasvir-based regimen if eGFR was < 30 mL/min. Ribavirin was only added and given to patients that were non-anemic [26–28]. A cure for HCV infection was obtainable for the majority of HD and KTx patients [27, 28], whereas this was not the case for CKD patients where there was a high rate of acute kidney injury [26]. However, in the setting of patients with impaired renal function, DAA therapy has a very high SVR and slows a rapid decline in eGFR associated with chronic HCV infec- tion [29]. Therefore, in the era of DAAs, HCV infection may be a reversible risk factor for CKD progression.
Beinhardt et al. reported that 96% of DAA-treated patients with renal impairment achieved an SVR after 12 and 24 weeks of treatment-free follow-up [30]. Likewise, other studies report that DAA therapy was highly effective in the setting of renal transplantation, with 100% of patients achieving viral clearance and similar SVR rates despite receiving immunosuppression comprising a calcineurin- inhibitor agent associated with, in most cases, low-dose ster- oids and mycophenolic acid [31–33]. In addition, in these studies, the viral response to DAAs was not affected by prior failure of alpha-interferon-based therapy, the timing of DAA therapy after transplantation, or the stage of liver fibrosis.
In our single-center, retrospective, cohort study, we tried to assess the effect of anemia at pre-treatment as a predictor for deleterious renal and extra-renal side effects of DAAs in CKD, HD, and KTx patients. In general, the prevalence of anemia is very high in the CKD population; indeed, when present, it is corrected by iron and/or erythropoietin therapy [34]. KDIGO guidelines state that anemia within CKD is diagnosed when hemoglobin level is < 11 g/dL [35]. How- ever, because of the reimbursement of erythropoietin policy in Egypt, i.e., only when Hb level is < 10.5 g/L, we chose a hemoglobin level of < 10.5 g/dL as the cut-off value. Thus, of our 235 patients, 98 (41.7%) had anemia: of these, 60%, 40%, and 32% were CKD, HD, or KTx patients, respectively. We found that DAA treatment was efficient, i.e., there was a significant decrease in aminotransferase levels in both ane- mic and non-anemic groups. It provided an SVR at 24 weeks of > 95% for HD and KTx. Conversely, a 24-week SVR was only obtained for 77.1% of CKD patients. However, being anemic when initiating DAA therapy did not influence anti- viral response across the three groups.
We found a significant drop in hemoglobin by 1 month after starting DAA treatment in all non-anemic groups, i.e., CKD, HD, and KTx patients. This could be explained by the use of ribavirin (200 mg/day) given to non-anemic CKD and KTx patients and 200 mg given every other day to non- anemic HD patients. Moreover, when ribavirin was stopped, anemia was reversed. This runs parallel to results obtained by other authors who report that ribavirin dose has to be re- adjusted or stopped when associated with anemia [36–38]. For example, in the RUBY-1 trial ribavirin-related anemia was common and led to its interruption in many patients and the need to start erythropoietin plus a blood transfu- sion, although this occurred more frequently in those with baseline anemia [39].
Baseline eGFR was less in our anemic group compared to the non-anemic group that had CKD or were KTx patients. This is concomitant with the fact that renal dysfunction is associated with anemia. In the CKD group, the rise in serum creatinine and the need for hemodialysis occurred signifi- cantly more frequently among the anemic group (p = 0.02 and p = 0.03, respectively).
A change in serum creatinine between baseline and at 1 month after starting treatment was significantly higher in the anemic group (compared to the non-anemic group: i.e., + 1.89 ± 0.96 vs. + 0.59 ± 0.45 mg/dL; p = 0.0001). In both groups, deterioration in renal function occurred more frequently with a ritonavir-boosted regimen, especially in the anemic group (p = 0.04). In both groups, DAAs was suspended during the period of AKI. The period of suspen- sion was extended from 3 weeks (7 patients) to 6 weeks (27 patients). Patients with an extended period of deteriorating renal function and that required hemodialysis for more than 8 weeks after DAAs were interrupted were considered to be end-stage renal-disease patients. As a consequence, we then considered them to be HD patients and, thus, resumed DAA therapy. The incidences of impaired graft function in KTx, and those with acute tubular necrosis (ATN) and acute cel- lular rejection were more frequent among our anemic group. A change in serum creatinine at 1 month after treatment (compared to baseline) was significantly greater among the anemic group that the non-anemic group (+ 0.25 ± 0.1 vs. + 0.04 ± 0.01 mg/dL; p = 0.0001). Acute-rejection epi- sodes were treated with pulses of IV methylprednisolone (10 mg/kg for 5 days): responses varied from partial recov- ery (three KTx) to complete recovery (one KTx).
Anemia itself is a risk factor for developing AKI [40, 41] and progressive CKD [42, 43]. In a normal physiologic response, the kidney receives 20—25% of the blood from cardiac output. This is the highest need throughout the body in relation to organ weight. As a pathologic response, ane- mia directly reduces the delivery of oxygen to the kidneys, particularly to the medulla. Because AKI frequently devel- ops under ischemic conditions, anemia can be a reason for the high incidence of AKI [44, 45].
In a recent study that included 494 patients with advanced chronic liver disease (ACLD) Scheiner et al. found that two-thirds suffered from anemia; in addition, the degree of hepatic dysfunction, portal hypertension, and episodes of hepatic decompensation correlated with the severity of anemia. Finally, anemic patients had worse overall 5-year survival and increased 5-year liver-related mortality [46].
Post-treatment hepatic decompensation was more fre- quent in our anemia group (12 cases vs. 2 cases). It was diagnosed by the development of ascites and lower-limb edema plus a concomitant rise in liver-enzyme levels and a decrease in serum-albumin levels. All cases of decompensa- tion were also associated with a relapse at some time point. Most cases received a ritonavir-boosted regimen. They also received supportive measures, including ursodeoxycholic acid, diuretics, and intravenous human albumin, when needed.
Our study has the advantage of being the first to study the effects of anemia on DAA efficacy and safety in CKD patients. We also included patients with different stages of CKD. The study also had a relatively large sample size.
However, lack of randomization, most patients were gen- otype 4, and the study being retrospective are limitations to our study. Also, we could not differentiate if deterioration in kidney function in the anemic groups during DAA therapy was related to anemia or to the already poor baseline kidney function.

Conclusion

In conclusion, access to effective oral DAA therapy for renal patients with HCV raises some logistical challenges; how- ever, despite this concern, we now (finally) have safe and effective all-oral DAA regimens that can reduce the burden of HCV-related complications in renal populations. Correc- tion of the associated medical disorders may improve the outcomes of DAAs. Anemia is a common feature of both renal and liver diseases; however, anemia did not affect DAA efficacy. But anemia was associated with a rise in serum cre- atinine among patients with CKD and KTx. Further studies are needed to optimize the outcomes of HCV treatment in renal patients.

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