Characteristics of patients with hepatitis C virus infection and antiviral treatment initiation in Taiwan: The MOSAIC study

Abstract

Hepatitis C virus (HCV) infection is the leading cause of chronic liver diseases worldwide. Monitoring its epidemiology, diagnosis, and treatment patterns are important for the management of patients with chronic HCV infection from both individual and public health perspectives. The MOSAIC study was an observational study conducted in 20 countries, including Taiwan; its primary objective was to describe epidemiology and treatment initiation patterns in patients seeking HCV care. Of the 111 chronic HCV patients enrolled from Taiwan, 58 (52.3%) had not previously received treatment. HCV genotype 1 was reported in 58 (52.3%) patients, of whom the majority (n = 47; 81.0%) were identified as having subtype 1b. Sixty‐two (55.9%) patients had HCV RNA level > 800 000 IU/mL. Liver cirrhosis was found in 35 (29.3%) patients and was more prevalent in patients who previously received treatment (71.0%). Interferon (IFN)‐based treatment was started within 12 weeks from study inclusion in 12 (10.8%) patients, of whom 11 (91.7%) who had not previously received treatment. Anti‐HCV treatment was not recommended by physicians in 70 (71.4%) and was refused by 23 (23.5%) patients. The MOSAIC study provides data on the epidemiology of HCV infection and IFN‐based treatment decision patterns in Taiwan. Further studies are needed to observe the impact of IFN‐free treatment on the treatment selection pattern.

1. INTRODUCTION

Hepatitis C virus (HCV) infection and its related liver comorbidities are a global health problem. ¹ , ² , ³ , ⁴ , ⁵ , ⁶ , ⁷ World Health Organization (WHO) figures for 2015 indicated that the global number of people newly infected with HCV was ~1.75 million and that close to 71 million people lived with chronic HCV. ¹ The distribution of HCV‐positive individuals is not uniform worldwide, and the estimated infection prevalence was 6.2% in the WHO Western Pacific region population (115 million people infected), followed by 6.1% in the African region (60 million), 2.3% in the Eastern Mediterranean region (21 million), 2.0% in the South‐East Asia region (39 million), 1.6% in the European region (15 million), and 0.7% in the Americas (7 million). There are variations in HCV incidence and prevalence across and within countries, and spreading of disease throughout breaks in infection control practices and/or intravenous drug use is thought to contribute to this pattern. ¹ , ² , ⁷ Such variations are also observed in Asian regions and countries ² ; the prevalence of HCV infections in China, Japan, and South Korea is estimated to be 1.6%, 0.6% to 0.9%, and 0.6% to 1.1%, respectively. ¹ , ⁹ In comparison, the prevalence of HCV infections in Taiwan is noticeably higher, reportedly between 1.8% and 5.5%. ⁹ , ¹⁰ , ¹¹ In the period between 2014 and 2016, an average of 210 confirmed new HCV cases per year were reported to Taiwan's disease notification system. ¹²

Currently, six major HCV genotypes with multiple subtypes have been identified. ³ , ⁷ , ¹³ Globally, genotype 1 (GT1) is the most common (46.0%‐49.0%), followed by GT3 (18.0%‐22.0%), GT4 (13.0%‐17%), GT2 (11.0%‐12.0%), and GT6 and GT5 (<3.0%). ⁷ , ¹³ The distribution of HCV genotypes and subtypes varies substantially in different parts of the world with the highest diversity observed in China and Southeast Asia, where GT1 and GT6 account for >60.0% of all genotypes (35.2% and 30.8%, respectively). ⁷ In Taiwan, GT1 (48.8%) and GT2 (39.5%) are the most predominant, and the reported prevalence of subtypes 1b and 2a were 45.5% and 37.0% to 39.5%, respectively. ⁸ , ¹³ However regional differences do exist within Taiwan as well, and in the southeastern area, GT1 was reported as the predominant HCV genotype (43.7%), with 36.4% of subtype 1b, followed by genotype GT2 (37.0%), with 26.8% of subtype 2a. ¹¹ The HCV genotype is a prognostic factor for both therapeutic responses to various HCV treatments, and liver disease progression and overall prognosis. ³ , ¹¹

Approximately 20.0% to 30.0% of those who are newly infected with HCV spontaneously clear the virus. However, a substantial number of infected individuals progress to liver cirrhosis and/or hepatocellular carcinoma. ⁴ , ⁵ , ⁶ , ¹⁴ Although the period between HCV infection and developing the end‐stage liver disease (ESLD) is highly variable, on average ~10.0% to 20.0% of the HCV‐positive population progresses to ESLD within 10‐20 years following infection. ⁴ Besides affecting the liver, HCV may also be associated with extrahepatic complications such as chronic fatigue, autoimmune conditions, renal diseases, and lymphomas. ¹⁵ , ¹⁶ The overall number of annual deaths attributed to HCV‐related diseases appears to be on the rise, and the latest figures from the WHO reports estimate that in 2015 the number of deaths from end‐stage HCV infection was 399 000. ¹

The standard of care for hepatitis C has been evolving rapidly in the last decade. The recent introduction of direct‐acting antivirals (DAAs) has revolutionized HCV treatment and prognosis, with reported cure rates of >95.0%. Despite this, chronic HCV patients in many countries still receive interferon (IFN)‐based therapy. ¹ , ³ Before 2017, the IFN‐based therapy was the standard treatment reimbursed for HCV infection in Taiwan, and there have been accumulating evidence showing the HCV treatment outcomes and impacts in the general population, ¹⁷ as well as in special populations such as hepatitis B/C dual‐infected patients or patients receiving methadone maintenance treatment. ¹⁸ , ¹⁹ Apart from achieving sustained virological response (SVR), extra benefits of successful IFN‐based antiviral therapies have been seen in the reduction of the post‐treatment transfusion demand in thalassemic patient with chronic hepatitis C and in the reduction of the risk of gastric cancer and non‐Hodgkin lymphoma, ²⁰ , ²¹ but not in the incidence of systemic lupus erythematosus or rheumatoid arthritis. ²² The global strategy on managing viral hepatitis (including HCV), which accommodates the availability of new DAA treatment (through approval and funding by the health care system), is being developed and expanded at either regional and/or country levels. ¹⁷ , ²³ , ²⁴ , ²⁵ , ²⁶ In Taiwan, real‐world cost‐effectiveness of IFN‐based therapies studies of both treatment‐naïve and treatment‐experienced chronic HCV patients, ²⁷ , ²⁸ as well as models for prioritization have facilitated the transition from IFN‐containing to IFN‐free DAA regimens. ²⁹ , ³⁰ New DAAs have been reimbursed by the Taiwanese national health insurance since 2017, ultimately substantially expanding treatment options for patients with HCV infection. ³¹

The MOSAIC study was an international observational study providing data on the epidemiology, as well as humanistic and economic outcomes of HCV treatment. The interim analysis of data from the Taiwanese cohort collected during phase 1 of the study summarizes demographic and clinical characteristics relevant to chronic HCV infection, including factors influencing decision‐making in treatment initiation. In the MOSAIC study, the patients enrolled in Taiwan from August 1, 2014, to July 30, 2015, had the access mostly to IFN‐based regimens because the new DAAs became available in clinical practice in Taiwan only at the end of 2016. ³¹

2. METHODS

2.1. Study design

The International Multicenter Prospective Observational Study to Evaluate the Epidemiology, Humanistic and Economic Outcomes of Treatment for Chronic Hepatitis C Virus (MOSAIC) study was designed to evaluate various aspects of chronic HCV infection and outcomes of HCV treatment. It was conducted in 30 countries across different geographical regions, including Taiwan. The study comprised three phases, each with distinct objectives. In phase 1, patients were assessed for the presence of chronic HCV infection and eligibility for enrollment into the study. The objective of phase 1 was to describe the epidemiology of patients seeking care for HCV and for whom an IFN‐containing regimen was considered as a treatment option. Patients who commenced treatment within 12 weeks of study enrollment continued to phase 2, while for the remaining patients, the study ended with phase 1. During phase 3, patients were followed up at 4, 12, and 48 weeks after commencing IFN‐based treatment. The MOSAIC study design is outlined in Figure 1.

FIGURE 1.

Design of current study

In this article, we present data collected from the Taiwanese cohort during phase 1 of the MOSAIC study in the period from August 1, 2014, and July 30, 2015. The study was approved by the Ethical Committee of the National Taiwan University Hospital (NTUH‐IRB 201412039RSD).

2.2. Study population and data collection

Patients aged ≥18 years who presented with chronic HCV infection that was untreated at enrollment and who were willing to provide an informed consent were included in this study, regardless of HCV genotype, treatment history, comorbidities, and concomitant therapy. Patients with acute HCV infection, with chronic HCV infection that was under treatment at the time of enrollment, or who were participating in concurrent interventional clinical trials were excluded.

The patients‐enrolled population comprised of patients not previously treated and patients previously treated who entered the study in phase 1 and fulfilled all eligibility criteria. Eligible patients who did not enter the study at all were considered nonparticipants. For these patients, the investigators captured only the age range and the reason for not entering the study. Both populations combined (enrolled patients and nonparticipants) formed all‐patients group.

The present analysis was conducted on data collected in the enrolled population toward phase 1 and available in the database on September 10, 2015 (with a clinical cutoff date of July 30, 2015). Data collected for the analysis included demographics, basic clinical characteristics of chronic HCV infection such as HCV genotype, viral RNA load, serology, HCV treatment history and its outcome, liver disease (fibrosis) status, and relevant comorbidities. As this study is observational in nature, the methodology of virological tests and fibrosis stage determination was based on the procedures and analytic pipelines established by each laboratory of each participating hospital. Details of anti‐HCV regimen prescribed to those patients in whom such treatment was planned as well as reasons for not initiating IFN‐containing HCV treatment within 12 weeks from enrollment in the remaining patients were also collected. The patients who have not started IFN‐containing HCV treatment within 12 weeks from enrollment were not included in the next phases of the study.

2.3. Statistical analysis

Descriptive statistics were applied to data on patient demographics, clinical characteristics, and treatment. The data were summarized by pretreatment status, by treatment group, or pretreatment status and cirrhosis status.

All statistical analyses were performed using SAS software (version 9.4; The SAS Institute, Cary, North Carolina), and a P‐value <.05 was considered statistically significant.

3. RESULTS

3.1. Patient disposition

A total of 118 patients with chronic HCV infection (all‐patients group) were enrolled at four sites across Taiwan (Figure 2). Data from 111 of these patients were analyzed (patients‐enrolled population), while data from seven patients were not considered because these patients responded to previous treatment—they no longer presented with chronic HCV.

FIGURE 2.

Flow of our patients

3.2. Patient characteristics

Baseline demographic data for the patients‐enrolled population are summarized in Table 1. Median age at enrollment was 62.0 years (range, 33.0‐82.0 years) with the majority (n = 96; 86.5%) of patients being >50 years of age. Almost two‐thirds (64.9%) of the enrolled population were female. Of the enrolled population, 58 (52.3%) patients had not previously received treatment, and 53 (48.7%) patients had previously received treatment. All enrolled patients were Asian, and overall demographic patterns analyzed (sex and age) were similar in both previously untreated and previously treated patients.

TABLE 1.

Patient characteristics of the enrolled population

	Total (N = 111)	Not previously treated (n = 58)	Previously treated (n = 53)
Sex, n (%)
Male	39 (35.1)	22 (37.9)	17 (32.1)
Female	72 (64.9)	36 (62.1)	36 (67.9)
Age, year
Mean (SD)	60.9 (10.34)	60.8 (11.28)	61.1 (9.31)
Median	62	63	61
Q1–Q3	54‐68	54‐69	58‐66
Range	33‐82	33‐80	33‐82
Number in age range, y, n (%)
30‐40	5 (4.5)	3 (5.2)	2 (3.8)
41‐50	10 (9.0)	6 (10.3)	4 (7.5)
51‐60	36 (32.4)	17 (29.3)	19 (35.8)
>60	60 (54.1)	32 (55.2)	28 (52.8)
HCV RNA at enrollment, n (%)
Detectable ≤800 000 IU/mL	34 (30.6)	17 (29.3)	17 (32.1)
>800 000 IU/mL	62 (55.9)	28 (48.3)	34 (64.2)
Positive qualitative test	15 (13.5)	13 (22.4)	2 (3.8)
HCV genotype a , n (%)
GT 1	58 (52.3)	22 (37.9)	36 (67.9)
Non‐GT 1	29 (26.1)	15 (25.9)	14 (26.4)
Unknown	24 (21.6)	21 (36.2)	3 (5.7)
HCV GT1 subtype, n (%)
1a	5 (8.6)	2 (9.1)	3 (8.3)
1b	47 (81)	19 (86.4)	28 (77.8)
Unknown	6 (10.3)	1 (4.5)	5 (13.9)
N	58	22	36
Outcome of the last HCV treatment b , n (%)
Breakthrough	3 (5.7)	‐	3 (5.7)
Null response	7 (13.2)	‐	7 (13.2)
Relapse	32 (60.4)	‐	32 (60.4)
SVR followed by reinfection	1 (1.9)	‐	1 (1.9)
Discontinued	10 (18.9)	‐	10 (18.9)
N	53		53 (100)

Abbreviations: HCV, hepatitis C virus; SVR, sustained virological response; VR, virological response.

^a Patients with multiple genotypes were assigned to disjoint groups according to the following hierarchy: GT1, GT4, GT3, GT2, GT5, GT6.

^b VR has been defined as follows: breakthrough (reappearance of HCV RNA at any time during treatment after VR); null response (<2 log10 IU/mL decrease in HCV RNA level from baseline to week 12 of therapy); partial response (≥2 log10 IU/mL decrease in HCV RNA level from baseline to week 12 of therapy, but no VR); relapse (HCV RNA undetectable at end of treatment and detectable thereafter); SVR (undetectable HCV RNA level [<50 IU/mL] 24 weeks after treatment).

All patients were positive for HCV RNA at enrollment. Sixty‐two (55.9%) patients had a viral RNA load >800 000 IU/mL, and in 34 (30.6%) patients, HCV RNA was detected to be ≤800 000 IU/mL (Table 1).

Of the 87 patients whose HCV genotype was known, the majority (n = 58; 66.7%) had GT1, and in 29 (33.3%) patients, the genotype was classified as non‐GT1. Subtype 1b accounted for 42.3% of tested patients and 81.0% (n = 47) of patients presenting with HCV GT1. The proportion of patients with HCV GT1 was higher in patients who had previously received treatment in comparison with patients who had not (67.9% vs 37.9%). The proportion of patients with HCV non‐GT1 was similar in both groups (25.9% and 26.4%, respectively). The HCV genotype was reported to be unknown in a larger proportion of patients who had not previously received treatment than in the group of patients who had (36.2% vs 5.7%).

The outcome of the last HCV treatment before enrollment, including virological response, was known for all 53 previously treated patients and is summarized in Table 1. The most common outcome was “relapse,” reported in 32 (60.4%) patients. This was followed by “treatment discontinued” (n = 10; 18.9%), “null response” (n = 7; 13.2%), “breakthrough” (n = 3; 5.7%), and “sustained virological response followed by reinfection” (n = 1; 1.9%).

3.3. Cirrhosis status by pretreatment status and genotype

Data on cirrhosis status were available for 61 (55.0%) patients in the enrolled population. More than half (57.4%) of these patients presented with liver cirrhosis, and more frequently in the previously treated group (71.0%) in comparison with the previously untreated group (43.3%) (P = .03 by univariate logistic regression) (Table 2). Cirrhosis (minimal or no fibrosis and/or portal fibrosis) was reported as absent in 26 (42.6%) patients. The majority of patients with cirrhosis (33/35 patients; 94.3%) were classified as compensated, and the two cases with decompensated liver cirrhosis were in the previously treated group.

TABLE 2.

Pretreatment cirrhosis status

Cirrhosis status	Total (N = 111)	Not previously treated (n = 58)	Previously treated (n = 53)
Cirrhosis status (detailed), n (%)
Minimal or no fibrosis	24 (39.3)	17 (56.7)	7 (22.6)
Portal fibrosis	2 (3.3)	‐	2 (6.5)
Cirrhosis a	35 (57.4)	13 (43.3)	22 (71)
N	61	30	31
Cirrhosis status (functional), n (%)
Compensated cirrhosis	33 (94.3%)	13 (100.0%)	20 (90.9%)
Decompensated cirrhosis	2 (5.7%)	‐	2 (9.1%)
N	35	13	22

^a Cirrhosis or transition to cirrhosis vs no cirrhosis tested with univariate logistic regression: P‐value = .0316.

Analysis of cirrhotic status by genotype and pretreatment status (Table 3) indicates that the proportion of cirrhosis was the highest in patients infected with HCV GT1 (19/35 patients; 54.3%). Of the 19 patients with HCV GT1 and cirrhosis, 15 had previously received treatment (78.9%).

TABLE 3.

HCV genotype by pretreatment cirrhosis status

		Total	GT1	Non‐GT1	Unknown
N/n (%)		111 (100)	58 (52.3)	29 (26.1)	24 (21.6)
Cirrhosis (%)	Total	35 (31.5)	19 (54.3)	7 (20.0)	9 (25.7)
	Not previously treated	13 (37.1)	4 (21.1)	2 (28.6)	7 (77.8)
	Previously treated	22 (62.9)	15 (78.9)	5 (71.4)	2 (22.2)
No cirrhosis (%)	Total	26 (23.4)	8 (30.8)	9 (34.6)	9 (34.6)
	Not previously treated	17 (65.4)	4 (50.0)	5 (55.6)	8 (88.9)
	Previously treated	9 (34.6)	4 (50.0)	4 (44.4)	1 (11.1)
Unknown (%)	Total	50 (45.0)	31 (62.0)	13 (26.0)	6 (12.0)
	Not previously treated	28 (56.0)	14 (45.2)	8 (61.5)	6 (100.0)
	Previously treated	22 (44.0)	17 (54.8)	5 (38.5)	0 (0.0)

3.4. Disposition of patients who initiated HCV treatment

Twelve (10.8%) patients from the enrolled population were scheduled to commence IFN‐based treatment within 12 weeks of enrollment, and of these, 11 (91.7%) had not previously received treatment. Eleven (91.7%) patients were prescribed a pegylated IFN/IFN‐based combination treatment, and one patient started other treatment with no information about a specific regimen. None of the 11 patients with known treatment received DAAs as a part of HCV treatment; 10 (83.3%) patients commenced with the regimen containing pegylated IFN‐α with RBV.

In total 29 (26.1%) patients in the enrolled population were considered an intention‐to‐treat group, including 12 (10.8%) patients who were scheduled for treatment, 12 (10.8%) patients planned to be enrolled in interventional clinical trials, and five (4.5%) patients for whom treatment was postponed beyond 12 weeks from enrollment.

3.5. Reasons for not starting HCV treatment

The majority of enrolled patients (n = 99; 89.2%) in the study did not start IFN‐based treatment within 12 weeks of study inclusion (Table 4). The reasons for not starting treatment have been categorized as (a) treatment postponed by >12 weeks, (b) treatment not recommended by the physician, and (c) patient refused treatment. Selection of multiple reasons per patient and category were possible, but each patient was counted only once for each category.

TABLE 4.

Reasons for not starting treatment

Reason a	Total (n = 98 b )	Not previously treated (n = 46 b )	Previously treated (n = 52)
Treatment postponed > 12 weeks, n (%)	5 (5.1)	4 (8.7)	1 (1.9)
Treatment not recommended by physician, n (%)	70 (71.4)	30 (65.2)	40 (76.9)
Contraindication to IFN	2 (2)	1 (2.2)	1 (1.9)
Presumed lack of efficacy	9 (9.2)	‐	9 (17.3)
Presumed tolerability issue	4 (4.1)	2 (4.3)	2 (3.8)
Planned to be enrolled in interventional clinical trial	12 (12.2)	5 (10.9)	7 (13.5)
Waiting for future IFN‐based treatment option	5 (5.1)	3 (6.5)	2 (3.8)
Waiting for IFN‐free treatment option	14 (14.3)	5 (10.9)	9 (17.3)
Other	24 (24.5)	14 (30.4)	10 (19.2)
Patient refused treatment, n (%)	23 (23.5)	12 (26.1)	11 (21.2)
Presumed lack of efficacy	2 (2)	‐	2 (3.8)
Presumed tolerability issue	13 (13.3)	6 (13.0)	7 (13.5)
Presumed impact on ability to work	2 (2)	2 (4.3)	0
Cost	1 (1)	1 (2.2)	9 (17.3)
Waiting for IFN‐free treatment option	4 (4.1)	2 (4.3)	2 (3.8)
Other	1 (1)	1 (2.2)	0

Abbreviation: IFN, interferon.

^a Multiple reasons per patient and category were possible, but each patient was counted only once for each main category: (a) treatment postponed >12 weeks, (b) treatment not recommended by the physician, and (c) patient refused treatment.

^b Information for one patient (1.0%) from the previously untreated group was missing and not included at the time.

In the majority of enrolled patients, HCV treatment was not recommended by the physician (n = 70; 71.4%), while 23 (23.5%) patients refused treatment, and in five (5.1%) patients, treatment was postponed beyond 12 weeks from enrollment.

In general, potential or expected efficacy and/or tolerability issues with currently available treatment were reported by the physician and/or patient as some of the major reasons for not starting IFN‐based treatment. Such concerns were reported more frequently by patients (n = 17/23; 74.0%) than by physicians (n = 15/70; 21.4%).

4. DISCUSSION

The natural history of HCV infection is associated with several demographic, virological, clinical, and lifestyle factors; with significant variations among different populations and geographical regions, as well as overtime. ¹ The results presented in this article are based on real‐world data on the epidemiology of chronic HCV infection and treatment decision patterns obtained from four centers participating in the MOSAIC study. The enrolled population included 111 adult patients with virologically confirmed chronic HCV infection who had not been treated before enrollment and who were registered at four specialized clinical centers between August 1, 2014, and July 30, 2015. Patient characteristics, including demographics, actual HCV load, and HCV genotype, the clinical status of liver disease (including the presence of fibrosis/cirrhosis), and treatment history have been explored in phase 1 of the MOSAIC study.

Worldwide variation in the prevalence of HCV genotypes and subgenotypes is well known. ³ , ⁷ , ¹³ , ³² In Taiwan, HCV GT1 is the most common genotype, and GT1b is the most common subtype, followed by GT2 (subtype 2a); there exist regional variations within the country in proportions of genotypes and subgenotypes. ⁷ , ¹¹

The genotype of HCV may have an impact on therapeutic response and liver disease progression, and this information is important for developing strategies to manage and/or eliminate HCV infection. ³ , ¹¹ , ³³ , ³⁴ In the Taiwanese cohort of the MOSAIC study, HCV GT1 was found to be the most prevalent genotype (52.3%), and subtype 1b was the most common subtype (42.3%; 81.0% of GT1). These results reiterate previously reported findings. ⁷ , ¹¹

Most patients with acute HCV infection develop a chronic infection with a high risk of developing associated liver diseases. ¹ , ⁴ , ⁵ , ⁶ , ³³ In general, HCV treatment is recommended for all patients with chronic HCV infection, with a long‐term aim of reducing all‐cause mortality and incidence of liver‐related diseases, including ESLD and hepatocellular carcinoma. ³ , ²³ , ³⁴ Although the selection of treatment for chronic hepatitis C considers the HCV genotype, the presence or absence of cirrhosis is the most relevant decision‐making factor from a clinical standpoint, and the priority for treatment initiation depends largely on the degree of liver fibrosis. ³ , ²⁹ , ³⁰ , ³⁴ In the Taiwanese cohort of the MOSAIC study, 61 (55.0%) patients had liver histopathology results, and of those, 35 (57.4%) were diagnosed with liver cirrhosis. As expected, the proportion of patients with cirrhosis was higher (71.0%) in the previously treated group than in the previously untreated group (43.3%), which is consistent with other reports. ³³ , ³⁵

The use of DAA‐based regimens, instead of those based on pegylated IFN, has been recommended to treat HCV infection for some time now. However, the availability of DAAs within local healthcare systems, including their approval and funding, is a known limiting factor in the HCV treatment selection. ³ , ¹⁷ , ³⁰ , ³⁴ A nationwide survey published in 2015 was conducted at the patient level (58 129 residents) and involved 89 gastroenterologists/hepatologists exploring disease awareness, treatment accessibility, recommendations, acceptance, and barriers to anti‐HCV therapy with IFN‐based treatments before wider availability of DAA‐based regimens in Taiwan. ³⁵ Reported recommendation/acceptance rate of anti‐HCV IFN‐based treatment was at the level of 70.6%, which seems to be higher than in the MOSAIC study, where currently available IFN‐based treatments were not recommended by the physician in 71.4% of cases and were refused by 23.5% of patients.

Among reasons for not starting IFN‐based treatment, concerns about its side effects seem to have the biggest impact on the decision to initiate treatment. The major treatment barriers reported in the survey ³⁵ were fear of adverse events (37.0%), major disorders (17.6%), ineligibility for insurance reimbursement (17.6%), and lack of therapy awareness (11.3%). In the MOSAIC study, physicians reported presumed tolerability issues and/or contraindications to IFN treatment in 6.1% of cases. However, waiting for IFN‐free treatment options was indicated or planning patient enrollment in interventional clinical trial was reported in 14.3% and 12.2% of cases, respectively (26.5% in total).

In the MOSAIC study, the overall reported rate of initiating IFN‐based treatments within 12 weeks from enrollment (10.8% of patients) was comparable with the anti‐HCV treatment initiation rate from the survey, with reported rates of 10.1% and 13.7% for anti‐HCV‐seropositive and HCV‐viremic population. ³⁵ However, 29 (26.1%) patients in the MOSAIC cohort could be considered an intention‐to‐treat population, with 12 (10.8%) patients starting IFN‐/RBV‐based treatment within 12 weeks from enrollment, 5 (5.1%) patients for whom such treatment was postponed beyond 12 weeks, and 12 (10.8%) patients who were set to be enrolled in interventional clinical trials.

The actual sample size and limited geographical coverage (four centers in Taiwan participating in the study) are the most important factors precluding conclusive analysis of the data from the Taiwanese cohort. Furthermore, this study does not allow a comparison of specific subpopulations, such as patients on maintenance hemodialysis or injectable drug users. However, the MOSAIC study provides real‐world data on the epidemiology of HCV infection and treatment decision patterns before the routine availability of DAAs in Taiwan. Further studies are required to assess the impact of wider availability of new IFN‐free DAA treatments on the regional/national strategy of HCV cure in Taiwan. ²⁵ , ²⁶

5. CONFLICT OF INTEREST

All authors declare no conflict of interest.

Yu M‐L, Tsai W‐L, Chu C‐J, Kao J‐H. Characteristics of patients with hepatitis C virus infection and antiviral treatment initiation in Taiwan: The MOSAIC study. Kaohsiung J Med Sci. 2021;37:245–252. 10.1002/kjm2.12317