Direct acting antiviral treatment of chronic hepatitis C in Denmark: factors associated with and barriers to treatment initiation

Hepatitis C virus RNA is 5'-capped with flavin adenine dinucleotide

RNA viruses have evolved elaborate strategies to protect their genomes, including 5' capping. However, until now no RNA 5' cap has been identified for hepatitis C virus^1,2 (HCV), which causes chronic infection, liver cirrhosis and cancer³. Here we demonstrate that the cellular metabolite flavin adenine dinucleotide (FAD) is used as a non-canonical initiating nucleotide by the viral RNA-dependent RNA polymerase, resulting in a 5'-FAD cap on the HCV RNA. The HCV FAD-capping frequency is around 75%, which is the highest observed for any RNA metabolite cap across all kingdoms of life^4-8. FAD capping is conserved among HCV isolates for the replication-intermediate negative strand and partially for the positive strand. It is also observed in vivo on HCV RNA isolated from patient samples and from the liver and serum of a human liver chimeric mouse model. Furthermore, we show that 5'-FAD capping protects RNA from RIG-I mediated innate immune recognition but does not stabilize the HCV RNA. These results establish capping with cellular metabolites as a novel viral RNA-capping strategy, which could be used by other viruses and affect anti-viral treatment outcomes and persistence of infection.

High real-world effectiveness of 12-week elbasvir/grazoprevir without resistance testing in the treatment of patients with HCV genotype 1a infection in Norway

BACKGROUND AND AIMS

The recommended treatment duration of hepatitis C virus (HCV) genotype 1a (GT1a) infection with elbasvir/grazoprevir (EBR/GZR) in the presence of a high baseline viral load and resistance associated substitutions (RAS) is 16 weeks with ribavirin added. The objective of this study was to evaluate the real-world effectiveness of 12 weeks of EBR/GZR without ribavirin and regardless of baseline viral load and RAS testing.

METHOD

This retrospective, observational cohort study was performed at five Norwegian hospitals that did not systematically utilize RAS testing. All adult patients with chronic HCV GT1a and compensated liver disease who had received 12 weeks of EBR/GZR without ribavirin and baseline RAS testing, were included. The primary endpoint was sustained virologic response at week 12 (SVR12), or if not available, at week 4 (SVR4).

RESULTS

We included 433 patients and attained SVR data on 388. The mean age was 45.7 years (22-73 years). 67.2% were male. HIV co-infection was present in 3.8% (16/424) and cirrhosis in 4% (17/424). The viral load was >800 000 IU/mL in 55.0% (235/427) of patients. Overall SVR was achieved in 97.2% (377/388). SVR was achieved in 98.3% (169/172) of those with viral load ≤800 000 IU/mL and in 96.2% (202/210) of those with viral load >800 000 IU/mL.

CONCLUSION

We observed high SVR rates among patients with HCV GT1a infection treated with EBR/GZR for 12 weeks without ribavirin, with no regard to baseline viral load and no RAS testing.

Integrating Management of Hepatitis C Infection into Primary Care: the Key to Hepatitis C Elimination Efforts

Elimination of hepatitis C virus (HCV), a leading cause of liver disease in the USA and globally, has been made possible with the advent of highly efficacious direct acting antivirals (DAAs). DAA regimens offer cure of HCV with 8-12 weeks of a well-tolerated once daily therapy. With increasingly straightforward diagnostic and treatment algorithms, HCV infection can be managed not only by specialists, but also by primary care providers. Engaging primary care providers greatly increases capacity to diagnose and treat chronic HCV and ultimately make HCV elimination a reality. However, barriers remain at each step in the HCV cascade of care from screening to evaluation and treatment. Since primary care is at the forefront of patient contact, it represents the ideal place to concentrate efforts to identify barriers and implement solutions to achieve universal HCV screening and increase curative treatment.

Factors Associated with the Refusal of Direct-Acting Antiviral Agents for the Treatment of Hepatitis C in Taiwan

Background and Objectives: Direct-acting antiviral agents (DAA) are a safe and highly effective treatment for hepatitis C virus (HCV) infection. However, the uptake of DAA treatment remains a challenge. This study aims to examine the reasons for DAA refusal among HCV patients covered by the Taiwan National Health Insurance system. Materials and Methods: This retrospective observational study covered the period from January 2009 to December 2019 and was conducted at a single hepatitis treatment center in Taiwan. This study involved chart reviews and phone-based surveys to confirm treatment status and refusal causes. To confirm treatment status, subjects with HCV without treatment records were phone-contacted to confirm treatment status. Patients who did not receive treatment were invited back for treatment. If the patient refused, the reason for refusal was discussed. Results: A total of 3566 patients were confirmed with DAA treatment; 418 patients (179 patients who were lost to contact or refused the survey and 239 patients who completed the survey of DAA refusal) were included in the no-DAA-therapy group. Factors associated with receiving DAAs were hemoglobin levels, hepatitis B virus co-infection, and regular gastroenterology visits. Meanwhile, male sex, platelet levels, and primary care physician visits were associated with DAA refusal. The leading causes of treatment refusal were multiple comorbidities, low health literacy, restricted access to hospitals, nursing home residence, and old age. The rate of DAA refusal remains high (10%). Conclusions: The reasons for treatment refusal are multifactorial, and addressing them requires complex interventions.

A multi-level intervention to eliminate hepatitis C from the Region of Southern Denmark: the C-Free-South project

Denmark has signed the WHO strategy to eliminate hepatitis C virus (HCV). In the absence of a national strategy for elimination, a local action plan was developed in the Region of Southern Denmark (RSD). The aim of the strategy is to diagnose 90% of HCV-infected persons and treat 80% of those diagnosed by 2025. The strategy was developed by reviewing Danish data on HCV epidemiology and drug use to identify key populations for screening, linkage to care, and treatment. Based on available published data from 2016, an estimated 3028 persons in the RSD were HCV-RNA positive (population prevalence 0.21%). Of these, 1002 were attending clinical care, 1299 were diagnosed but not in clinical care, and 727 were undiagnosed. Three different interventions targeting the HCV-infected population and two interventions for HCV surveillance are planned to achieve elimination. The “C-Free-South” strategy aims to eliminate HCV in our region by identifying (90%) and treating (80%) of infected persons by the end of 2025, 5 years earlier than the WHO elimination target date.

Against All Odds? Addiction History Associated with Better Viral Hepatitis Care: A Dutch Nationwide Claims Data Study

The elimination of viral hepatitis in target populations is crucial in reaching WHO viral hepatitis elimination goals. Several barriers for the treatment of viral hepatitis in people with addictive disorders have been identified, yet nationwide data on hepatitis healthcare utilization (HCU) in these patients are limited. We investigated whether a history of addictive disorder is associated with suboptimal hepatitis HCU, indicating failure to receive diagnostic care or treatment. We identified all newly referred viral hepatitis patients in the Netherlands between 2014 and 2019 by query of the Dutch national hospital claims database. Each patient’s first year of HBV or HCV care activities was collected and clustered in two categories, ‘optimal’ or ‘suboptimal’ hepatitis HCU. Optimal HCU includes antiviral therapy. We tested the association between addiction history and HCU, adjusted for sex, age, migrant status, and comorbidity. In secondary analyses, we explored additional factors affecting hepatitis HCU. We included 10,513 incident HBV and HCV patients, with 13% having an addiction history. Only 47% of all patients achieved optimal hepatitis HCU. Addiction history was associated with less suboptimal HCU (adjusted OR = 0.73, 95% CI = 0.64–0.82). Migration background was associated with suboptimal HCU (OR = 1.62, 95% CI = 1.50–1.76). This study shows that addiction history is associated with higher viral hepatitis HCU; thus, this population performs better compared to non-addicted patients. However, less than 50% of all patients received optimal hepatitis care. This study highlights the need to improve hepatitis HCU in all patients, with a focus on migrant populations. Linkage to care in the addicted patients is not studied here and may be a remaining obstacle to be studied and improved to reach WHO viral hepatitis elimination goals.

Differences in the hepatitis C virus cascade of care and time to initiation of therapy among vulnerable subpopulations using a mobile unit as point-of-care

BACKGROUND AND AIMS

People who inject drugs (PWID) and other marginalized populations with high hepatitis C virus (HCV) infection rates represent a unique challenge for treatment initiation due to health, administrative and social barriers. We analysed the HCV cascade of care (CoC) in some vulnerable subpopulations in Madrid, Spain, when using a mobile point-of-care (PoC).

METHODS

From 2019 to 2021, a mobile unit was used to screen active HCV using a linkage-to-care and two-step PoC-based strategy. Viremic participants were grouped into four subgroups: PWID, homeless individuals and people with a mental health disorder (MHD) and alcohol use disorder (AUD). Logistic regression, and Cox and Aalen's additive models were used to analyse associated factors and differences between groups.

RESULTS

A prospectively recruited cohort of 214 HCV-infected individuals (73 PWID, 141 homeless, 57 with a MHD and 91 with AUD) participated in the study. The overall HCV CoC analysis found that 178 (83.1%) attended a hospital, 164 (76.6%) initiated direct-acting antiviral therapy and 141 (65.8%) completed therapy, of which 99 (95.2%) achieved sustained virological response (SVR). PWID were significantly less likely to initiate treatment, whereas individuals with AUD waited longer before starting the treatment. Both people with AUD and PWID were significantly less likely to complete HCV treatment.

CONCLUSIONS

Overall, SVR was achieved in the majority of the participants treated. However, PWID need better linkage to care and treatment, whereas PWID and AUD need more support for treatment completion.

High Sustained Virologic Response Rates of Glecaprevir/Pibrentasvir in Patients With Dosing Interruption or Suboptimal Adherence

INTRODUCTION

Pangenotypic, all-oral direct-acting antivirals, such as glecaprevir/pibrentasvir (G/P), are recommended for treatment of hepatitis C virus (HCV) infection. Concerns exist about the impact on efficacy in patients with suboptimal adherence, particularly with shorter treatment durations. These post hoc analyses evaluated adherence (based on pill count) in patients prescribed 8- or 12-week G/P, the impact of nonadherence on sustained virologic response at post-treatment week 12 (SVR12), factors associated with nonadherence, and efficacy in patients interrupting G/P treatment.

METHODS

Data were pooled from 10 phase 3 clinical trials of treatment-naive patients with HCV genotype 1-6 without cirrhosis/with compensated cirrhosis (treatment adherence analysis) and 13 phase 3 clinical trials of all patients with HCV (interruption analysis).

RESULTS

Among 2,149 patients included, overall mean adherence was 99.4%. Over the treatment duration, adherence decreased (weeks 0-4: 100%; weeks 5-8: 98.3%; and weeks 9-12: 97.1%) and the percentage of patients with ≥80% or ≥90% adherence declined. SVR12 rate in the intention-to-treat (ITT) population was 97.7% (modified ITT SVR12 99.3%) and remained high in nonadherent patients in the modified ITT population (<90%: 94.4%-100%; <80%: 83.3%-100%). Psychiatric disorders were associated with <80% adherence, and shorter treatment duration was associated with ≥80% adherence. Among 2,902 patients in the interruption analysis, 33 (1.1%) had a G/P treatment interruption of ≥1 day, with an SVR12 rate of 93.9% (31/33). No virologic failures occurred.

DISCUSSION

These findings support the impact of treatment duration on adherence rates and further reinforce the concept of "treatment forgiveness" with direct-acting antivirals.

Barriers to initiation of hepatitis C virus therapy in Germany: A retrospective, case-controlled study

Despite the availability of highly effective and well-tolerated direct-acting antivirals, not all patients with chronic hepatitis C virus infection receive treatment. This retrospective, multi-centre, noninterventional, case-control study identified patients with chronic hepatitis C virus infection initiating (control) or not initiating (case) treatment at 43 sites in Germany from September 2017 to June 2018. It aimed to compare characteristics of the two patient populations and to identify factors involved in patient/physician decision to initiate/not initiate chronic hepatitis C virus treatment, with a particular focus on historical barriers. Overall, 793 patients were identified: 573 (72%) who received treatment and 220 (28%) who did not. In 42% of patients, the reason for not initiating treatment was patient wish, particularly due to fear of treatment (17%) or adverse events (13%). Other frequently observed reasons for not initiating treatment were in accordance with known historical barriers for physicians to initiate therapy, including perceived or expected lack of compliance (14.5%), high patient age (10.9%), comorbidities (15.0%), alcohol abuse (9.1%), hard drug use (7.7%), and opioid substitution therapy (4.5%). Patient wish against therapy was also a frequently reported reason for not initiating treatment in the postponed (35.2%) and not planned (47.0%) subgroups; of note, known historical factors were also common reasons for postponing treatment. Real-world and clinical trial evidence is accumulating, which suggests that such historical barriers do not negatively impact treatment effectiveness. Improved education is key to facilitate progress towards the World Health Organization target of eliminating viral hepatitis as a major public health threat by 2030.

Global evolutionary analysis of chronic hepatitis C patients revealed significant effect of baseline viral resistance, including novel non-target sites, for DAA-based treatment and retreatment outcome

Direct-acting antivirals (DAAs) have proven highly effective against chronic hepatitis C virus (HCV) infection. However, some patients experience treatment failure, associated with resistance-associated substitutions (RASs). Our aim was to investigate the complete viral coding sequence in hepatitis C patients treated with DAAs to identify RASs and the effects of treatment on the viral population. We selected 22 HCV patients with sustained virologic response (SVR) to match 21 treatment-failure patients in relation to HCV genotype, DAA regimen, liver cirrhosis and previous treatment experience. Viral-titre data were compared between the two patient groups, and HCV full-length open reading frame deep-sequencing was performed. The proportion of HCV NS5A-RASs at baseline was higher in treatment-failure (82%) than matched SVR patients (25%) (p = .0063). Also, treatment failure was associated with slower declines in viraemia titres. Viral population diversity did not differ at baseline between SVR and treatment-failure patients, but failure was associated with decreased diversity probably caused by selection for RAS. The NS5B-substitution 150V was associated with sofosbuvir treatment failure in genotype 3a. Further, mutations identified in NS2, NS3-helicase and NS5A-domain-III were associated with DAA treatment failure in genotype 1a patients. Six retreated HCV patients (35%) experienced 2nd treatment failure; RASs were present in 67% compared to 11% with SVR. In conclusion, baseline RASs to NS5A inhibitors, but not virus population diversity, and lower viral titre decline predicted HCV treatment failure. Mutations outside of the DAA targets can be associated with DAA treatment failure. Successful DAA retreatment in patients with treatment failure was hampered by previously selected RASs.

Reasons for Not Seeking Hepatitis C Treatment among People Who Inject Drugs

Despite increases in treatment uptake for hepatitis C viral infection (HCV) in Australia since the introduction of direct acting antiviral (DAA) therapy, a large proportion of HCV-infected people who inject drugs (PWID) have not sought treatment. Purpose/Objectives: To examine predictors of treatment uptake and reasons for not seeking treatment among PWID. Methods: PWID (n = 404) recruited through five needle and syringe programs in South East Queensland were interviewed about HCV testing, status and treatment, recent injecting drug use, mental health and reasons for not taking up treatment. Predictors of treatment uptake were examined using unadjusted and adjusted logistic regression analyses. Proportions were calculated for participants reporting each reason for not taking up treatment. Results: We recruited 404 PWID. Of those tested for HCV (94%), 55% were HCV antibody positive and 31% with active infection. Approximately 36% of eligible participants had begun or completed DAA treatment. In adjusted analyses, injecting drugs three or more times per day was associated with not taking up HCV treatment (p = 0.005). Common reasons for not seeking treatment ("applied a lot") included experiencing no HCV-related symptoms (25%), HCV treatment not being a priority (23%), fear of treatment side effects (18%), and no knowledge of DAA treatments (15%). Conclusions/Importance: HCV education efforts for PWID should target misperceptions and lack of awareness of DAA therapy, and highlight the likely benefits of treatment even when asymptomatic. The use of peer workers and increased investment in integrated treatment facilities will likely aid treatment uptake.

The Copenhagen test and treat hepatitis C in a mobile clinic study: a protocol for an intervention study to enhance the HCV cascade of care for people who inject drugs (T'N'T HepC)

INTRODUCTION

Injecting drug use is the primary driver of hepatitis C virus (HCV) infection in Europe. Despite the need for more engagement with care, people who inject drugs (PWID) are hard to reach with HCV testing and treatment. We initiated a study to evaluate the efficacy for testing and linkage to care among PWID consulting peer-based testing at a mobile clinic in Copenhagen, Denmark.

METHODS AND ANALYSIS

In this intervention study, we will recruit participants at a single community-based, peer-run mobile clinic. In a single visit, we will first offer participants a point-of-care HCV antibody test, and if they test positive, then they will receive an HCV RNA test. If they are HCV-RNA+, we will administer facilitated referrals to designated 'fast-track' clinics at a hospital or an addiction centre for treatment. The primary outcomes for this study are the number of tested and treated individuals. Secondary outcomes include individuals lost at each step in the care cascade.

ETHICS AND DISSEMINATION

The results of this study could provide a model for targeting PWID for HCV testing and treatment in Demark and other settings, which could help achieve WHO HCV elimination targets. The Health Research Ethics Committee of Denmark and the Danish Data Protection Agency confirmed (December 2018/January 2019) that this study did not require their approval. Study findings will be disseminated through peer-reviewed publications, conference presentations and social media.

Will prior health insurance authorization for medications continue to hinder hepatitis C treatment delivery in the United States? Perspectives from hepatitis C treatment providers in a large urban healthcare system

Background

The recent introduction of direct acting antivirals for the treatment of hepatitis C virus (HCV) has dramatically improved treatment options for HCV infected patients. However, in the United States (US) treatment uptake has been low and time to initiation of therapy has been long. We sought to examine provider perspectives of facilitators and barriers to HCV treatment delivery.

Methods

From June to August 2019, we conducted in-depth, semi-structured interviews with medical staff providing HCV care as part of a university medical center in Los Angeles, CA. In order to understand the HCV treatment process, we interviewed key staff members providing care to the majority of HCV patients seeking care at the university medical center, including hepatologists and infectious disease specialists as well as key nursing and pharmacy staff. The interviews focused on workload and activities required for HCV treatment initiation for non-cirrhotic, treatment naïve patients.

Results

Providers noted that successful HCV treatment delivery was reliant on a care model involving close collaboration between a team of providers, in particular requiring a highly coordinated effort between dedicated nursing and pharmacy staff. The HCV care team overwhelmingly reported that the process of insurance authorization was the greatest obstacle delaying treatment initiation and noted that very few patient level factors served as a barrier to treatment uptake.

Conclusions

In the US, prior authorization for HCV treatment is a requirement for most public and private insurance plans. In an era with access to therapies that allow for a cure—and until revocation of prior authorization for HCV treatment is a reality—implementing strategies that can expedite authorization to accelerate treatment access are critical. Not only will this benefit patients, but it has the potential to help expand treatment to settings that are otherwise too resource strained to successfully deliver HCV care.

Framework for community-based models for treating hepatitis C virus

Objective Although community-based models for treating hepatitis C virus (HCV) are widely recognised for reaching more people who require treatment, little is known about their organisational and operational elements. This study aimed to address this gap and develop a framework for designing, implementing and evaluating community-based models for treating HCV. Methods This study was a systematic review in which 17 databases were searched for published and unpublished studies. The final search of databases was performed in September 2017. A qualitative inductive thematic approach was used to extract and categorise organisational and operational elements of community-based models for treating HCV. Results Data analysis yielded 13 organisational and operational elements that were categorised into three domains: support for patients, support for healthcare providers and service delivery facilitation. In the support for patients domain, support was categorised into four elements: peer support, psychological assessment and support, social assessment and support and adherence support. In the support for healthcare providers domain, the elements included the provision of educational opportunities for HCV care providers, specialist mentoring, decision making support and rewarding and recognition for HCV care providers. Finally, the service delivery facilitation domain included seven elements that target service-level enablers for community-based HCV treatment, including essential infrastructure, policy implementation and collocation and collaboration with other related services. Conclusion This framework for understanding the components of models of community-based HCV treatment may be used as a guide for designing, implementing and evaluating models of care in support of HCV elimination. HCV care providers and patients need to be supported to improve their engagement with the provision of community-based treatment. In addition, evidence-based strategies to facilitate service delivery need to be included. What is known about the topic? Community-based models for treating HCV are widely recognised as having the advantage of reaching more people who require treatment. These types of models aim to remove barriers related to accessibility and acceptability associated with tertiary centre-based HCV treatment. What does this paper add? Community-based models for treating HCV use various organisational and operational elements to improve the accessibility, effectiveness and acceptability of these services. The elements we identified target three main domains: support for patients with HCV, support for HCV care providers and service delivery facilitation. The importance of these organisational and operational elements designed to improve health and health services outcomes of community-based models for treating HCV is strongly influenced by context, and dependent on both the setting and target population. What are the implications for practitioners? Health policy makers and practitioners need to consider a patient’s psychosocial and economic status and provide support when needed. To successfully deliver HCV treatment in community settings, HCV care providers need to be trained and supported, and need to establish linkages, collaborations or colocations with other related services.

Evolutionary Pathways to Persistence of Highly Fit and Resistant Hepatitis C Virus Protease Inhibitor Escape Variants

Protease inhibitors (PIs) are important components of treatment regimens for patients with chronic hepatitis C virus (HCV) infection. However, emergence and persistence of antiviral resistance could reduce their efficacy. Thus, defining resistance determinants is highly relevant for efforts to control HCV. Here, we investigated patterns of PI resistance-associated substitutions (RASs) for the major HCV genotypes and viral determinants for persistence of key RASs. We identified protease position 156 as a RAS hotspot for genotype 1-4, but not 5 and 6, escape variants by resistance profiling using PIs grazoprevir and paritaprevir in infectious cell culture systems. However, except for genotype 3, engineered 156-RASs were not maintained. For genotypes 1 and 2, persistence of 156-RASs depended on genome-wide substitution networks, co-selected under continued PI treatment and identified by next-generation sequencing with substitution linkage and haplotype reconstruction. Persistence of A156T for genotype 1 relied on compensatory substitutions increasing replication and assembly. For genotype 2, initial selection of A156V facilitated transition to 156L, persisting without compensatory substitutions. The developed genotype 1, 2, and 3 variants with persistent 156-RASs had exceptionally high fitness and resistance to grazoprevir, paritaprevir, glecaprevir, and voxilaprevir. A156T dominated in genotype 1 glecaprevir and voxilaprevir escape variants, and pre-existing A156T facilitated genotype 1 escape from clinically relevant combination treatments with grazoprevir/elbasvir and glecaprevir/pibrentasvir. In genotype 1 infected patients with treatment failure and 156-RASs, we observed genome-wide selection of substitutions under treatment. Conclusion: Comprehensive PI resistance profiling for HCV genotypes 1-6 revealed 156-RASs as key determinants of high-level resistance across clinically relevant PIs. We obtained in vitro proof of concept for persistence of highly fit genotype 1-3 156-variants, which might pose a threat to clinically relevant combination treatments.

Transitioning from interferon-based to direct antiviral treatment options: A potential shift in barriers and facilitators of treatment initiation among people who use drugs?

BACKGROUND

Multiple barriers for accessing hepatitis C virus (HCV) treatment were identified during the interferon-based (IFN) treatment era for people who inject drugs (PWID). Whether these barriers persist since the introduction of IFN-free direct-acting antiviral (DAA) agents in Canada remains to be documented. This study examined temporal trends in HCV treatment initiation and associated factors during the transition from INF-based to all-oral DAA regimens.

METHODS

The study population was drawn from a prospective cohort of PWID in Montreal, Canada. At three-month/one-year intervals between 2011 and 2017, participants with chronic HCV infection completed an interviewer-administered questionnaire on socio-demographic characteristics, drug use and health service utilisation, including HCV treatment. Time-updated Cox multivariate regression models, stratified by DAA + INF (2011-2013) and all-oral DAA (2014-2017) availability periods, were conducted to examine associations between time to HCV treatment initiation and associated barriers and facilitators.

RESULTS

Of 308 participants (85% male, median age 42 [IQR: 33, 50]), 80 (26%) initiated HCV treatment during 915 person-years (PY). Incidence rates increased from 1.6 /100 PY (95%CI:0.9-2.6) in 2011 to 12.7 (10.6-15.1) in 2017 (p-trend = 0.0012). In multivariate analyses, visiting a primary care physician (2011-2013: aHR = 3.63[1.21-10.9]; 2014-2017: 2.52[1.10-5.77]) and frequent injection (0.23[0.05-0.99] and 0.49[0.24-0.99]) were consistently associated with treatment initiation. Participants aged >40 (2.27[1.24-4.13]), receiving opioid agonist therapy (OAT) (2.17[1.19-3.94]), and reporting prior HCV treatment (3.00[1.75-5.15]) were more likely to initiate treatment in the all-oral DAA period.

CONCLUSION

Treatment initiation increased between 2011 and 2017, but still remains low among PWID. Primary care visiting was a key facilitator regardless of the period, while engagement in OAT and health services, indicated by prior HCV treatment, increased the likelihood of treatment initiation in the DAA era. These findings suggest that access to health services is essential but not enough to scale up treatment in this population.