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Drug Authorization for Sofosbuvir/Ledipasvir (Harvoni) for Chronic HCV Infection in a Real-World Cohort: A New Barrier in the HCV Care Cascade

  • Albert Do ,

    Contributed equally to this work with: Albert Do, Yash Mittal

    ‡ These authors are co-first authors on this work.

    Affiliation Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States of America

  • Yash Mittal ,

    Contributed equally to this work with: Albert Do, Yash Mittal

    ‡ These authors are co-first authors on this work.

    Affiliation Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States of America

  • AnnMarie Liapakis,

    Affiliations Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States of America, Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America, Liver Transplantation Program, Yale-New Haven Hospital, New Haven, CT, United States of America

  • Elizabeth Cohen,

    Affiliation Liver Transplantation Program, Yale-New Haven Hospital, New Haven, CT, United States of America

  • Hong Chau,

    Affiliation Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America

  • Claudia Bertuccio,

    Affiliation Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America

  • Dana Sapir,

    Affiliation Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America

  • Jessica Wright,

    Affiliation Apothecary and Wellness Center, Yale-New Haven Hospital, New Haven, CT, United States of America

  • Carol Eggers,

    Affiliation Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America

  • Kristine Drozd,

    Affiliation Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America

  • Maria Ciarleglio,

    Affiliation Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America

  • Yanhong Deng,

    Affiliation Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America

  • Joseph K. Lim

    joseph.lim@yale.edu

    Affiliations Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States of America, Yale Liver Center, Section of Digestive Diseases, New Haven, CT, United States of America, Liver Transplantation Program, Yale-New Haven Hospital, New Haven, CT, United States of America

Abstract

Background

New treatments for hepatitis C (HCV) infection hold great promise for cure, but numerous challenges to diagnosing, establishing care, and receiving therapy exist. There are limited data on insurance authorization for these medications.

Materials and Methods

We performed a retrospective chart review of patients receiving sofosbuvir/ledipasvir (SOF/LED) from October 11-December 31, 2014 to determine rates and timing of drug authorization. We also determined predictors of approval, and those factors associated with faster decision and approval times.

Results

Of 174 patients prescribed HCV therapy during this period, 129 requests were made for SOF/LED, of whom 100 (77.5%) received initial approval, and an additional 17 patients (13.9%) ultimately received approval through the appeals process. Faster approval times were seen in patients with Child-Pugh Class B disease (14.4 vs. 24.7 days, p = 0.048). A higher proportion of patients were initially approved in those with Medicare/Medicaid coverage (92.2% vs. 71.4%, p = 0.002) and those with baseline viral load ≥6 million IU/mL (84.1% vs. 62.5%, p = 0.040). Linear regression modeling identified advanced fibrosis, high Model of End Stage Liver Disease (MELD) score, and female gender as significant predictors of shorter decision and approval times. On logistic regression, Medicare/Medicaid coverage (OR 5.96, 95% CI 1.66–21.48) and high viral load (OR 4.52, 95% CI 1.08–19.08) were significant predictors for initial approval.

Conclusions

Early analysis of real-world drug authorization outcomes between October-December 2014 reveals that nearly one in four patients are initially denied access to SOF/LED upon initial prescription, although most patients are eventually approved through appeal, which delays treatment initiation. Having Medicare/Medicaid and advanced liver disease resulted in a higher likelihood of approval as well as earlier decision and approval times. More studies are needed to determine factors resulting in higher likelihood of denial and to evaluate approval rates and times after implementation of restrictive prior authorization guidelines.

Introduction

Treatment of chronic hepatitis C (HCV) infection in the United States has been revolutionized with the development of novel direct-acting antiviral (DAA) therapies. DAA therapy has demonstrated better tolerability, adherence, as well as rates of sustained virologic response (SVR) and cure compared to antecedent interferon (IFN)-based therapies [14]. This advance has expanded the population of individuals with HCV infection who are potentially treatable. Owing to its efficacy, the American Association for the Study of Liver Disease (AASLD) and the Infectious Disease Society of America (IDSA) have modified their recommendations to include the combination of sofosbuvir and ledipasvir (SOF/LED) as first-line therapy for HCV genotype-1 infection, the most prevalent strain seen in the United States [3, 58].

However, care provision requires successful completion of numerous steps along a care continuum [9]. It has been recently estimated that only 16% of chronic HCV-infected individuals are prescribed antiviral treatment and only 9% achieve SVR [10] although this represents data from the interferon era and precedes the advent of all-oral anti-HCV regimens. The concept of a care cascade (diagnosis, linkage to care, retention in care, prescription of antiretroviral therapy, and viral suppression) has been utilized as a means for identifying care gaps and setting goals in patients with human immunodeficiency virus (HIV) infection, HCV-HIV co-infection, and recently for HCV mono-infected individuals as well [1115]. Recently, barriers to completion of therapy have been reported which include but are not limited to diagnosis, knowledge of treatment options, completion of pre-treatment paperwork, lack of insurance coverage, medical eligibility, lack of program infrastructure for vulnerable populations, and medication costs [1620]. To this effect, some interventions to improve access have also been proposed, such as provision for self-referral and shortened treatment duration [21, 22].

Among the steps in HCV treatment provision, pre-authorization (also known as prior authorization, prior approval, or pre-certification) is the process by which a health insurance provider determines that specific treatment is medically necessary, and which allows for insurance coverage of treatment cost. It is currently known that DAA therapy is expensive with prices ranging from $63,000 to $300,000 per treatment course. The wholesale cost of a 12-week treatment course of SOF/LED is $94,500, amounting to $1,125 per pill [23]. As this results in prohibitive cost and limited availability, pre-authorization often requires that patients have advanced fibrosis (grade F3 or beyond) or cirrhosis to be given treatment priority [24].

Currently there are limited data on rate and timing of insurance pre-authorization after SOF/LED prescriptions are written. In this study, we aim to perform a retrospective observational study reporting real-life data of drug approval rates in a cohort of patients with HCV infection who received prescription for SOF/LED treatment over a 3-month period. We also aim to determine factors associated with pre-authorization approval, time to pre-authorization decision, and time to pre-authorization approval. We hypothesize that the majority of patients for whom a pre-authorization request is filed will ultimately receive approval, and that insurance pre-authorization will be within the recommended guidelines for treatment for those with the highest need (i.e. advanced liver disease). However, we also hypothesize that there will be a proportion of patients who are ultimately not approved, as well as some who are approved only after appeal.

Materials and Methods

Study Subjects

As part of the SOF/LED acquisition process, all patients had pre-authorization requests sent to their insurance coverage providers. We reviewed the medical charts of all patients at Yale Liver Center who had an insurance pre-authorization request for SOF/LED filed between October 11, 2014 and December 31, 2014. Patients were then excluded if they received a prescription for HCV treatment other than combination SOF/LED.

Outcomes

For each patient, we recorded the insurance provider of pre-authorization request. Those without Medicare or Medicaid insurance carriers were categorized as having private insurance coverage. If a patient was listed as having both Medicaid/Medicare and another insurance provider, they were considered to have a private insurance provider. We recorded approval, denial, or pending status of pre-authorization initial request and appeal as of March 1st, 2015. If an individual was denied treatment and appeal was sought, date of appeal request and date of appeal decision were recorded.

Covariates

Patient characteristics included age, race, body mass index, co-morbid hypertension, psychiatric illness, diabetes, renal disease, hepatitis B or HIV co-infection, and baseline biochemical markers (total bilirubin, serum creatinine, and serum international normalized ratio, INR). We recorded HCV viral characteristics, including genotype, viral load, IL28B gene variant and prior treatment regimens. Severity of HCV infection was determined by progression of hepatic fibrosis. Those with METAVIR stage 4 fibrosis on liver biopsy, clinical hepatic decompensation, or imaging findings suggesting cirrhosis with portal hypertension were classified as having cirrhosis. Advanced fibrosis included those with cirrhosis and included individuals with grade 3 fibrosis on liver biopsy, advanced fibrosis by tissue elastography, and/or an elevated FIB-4 score (>3.25) [25]. In patients with cirrhosis, Child-Pugh class and MELD scores were recorded using laboratory testing closest to the pre-authorization filing date. A subset of patients received their pre-authorization request through their transplant clinic provider. It was noted for those whom this was the case.

Statistical Analysis

T-testing was used to compare continuous variables and chi-square testing was used for categorical variables. Univariate and multivariate analyses were performed using linear and logistic regression modeling with forward selection logistic regression to identify significant predictors of pre-authorization approval and times-to-decision or approval. All data were analyzed using SAS 9.4 statistical software (Cary, NC). Full dataset with SAS code used for this analysis is available at S1 Appendix.

Ethics Statement

We obtained approval for conduct of this study by our institutional review board.

Results

A total of 174 patients with chronic HCV infection seen at the Yale Liver Center were prescribed antiviral therapy between October 11th and December 31st 2014, of whom 129 were prescribed SOF/LED. Tables 13 summarize demographic characteristics of this patient population. The mean age was 57.0 ± 9.9 years with 61.2% being males. 60.5% of the population had cirrhosis. Table 4 summarizes the outcomes of pre-authorization. Of the 128 for whom pre-authorization status was determined, 100 (77.5%) received initial approval for pre-authorization. 117 (91.4%) of 129 received approval including those who required appeal. Initially, 19 patients (14.7%) required appeal and ultimately 6 (4.7%) were denied. As of March 1st, 2015, the pre-authorization status of 5 (3.9%) are pending and 1 (0.0%) is unknown. The average time to final decision (approval or denial) was 26.1 ± 25.2 days, and in those approved the average time to decision was 22.9 ± 21.2 days.

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Table 1. Baseline demographic information for patients prescribed SOF/LED from Yale non-transplant hepatology and transplant hepatology clinics from October 1, 2014 to December 30, 2014 (n = 129).

https://doi.org/10.1371/journal.pone.0135645.t001

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Table 2. Hepatitis C virus characteristics and disease severity.

https://doi.org/10.1371/journal.pone.0135645.t002

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Table 3. Baseline characteristics of patients with cirrhosis (n = 78).

https://doi.org/10.1371/journal.pone.0135645.t003

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Table 4. Pre-authorization outcomes for patients prescribed SOF/LED between October 11th-Dec 31st, 2014 (as of March 1st 2015).

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Table 5 summarizes the time-to-decision in all subjects with outcomes data and time-to-approval in those who were approved for pre-authorization. Females were found to have a significantly lower time-to-decision than males (19.8 vs. 30.0 days, p = 0.01) with a similar but non-significant finding in time-to-approval. Those with a Medicare/Medicaid had a shorter average time-to-decision and time-to-approval though this finding was not significant (22.6 vs. 28.7 days, p = 0.18 & 19.2 vs. 25.9 days, p = 0.08, respectively). Those with Child-Pugh class B cirrhosis had a significantly shorter approval time (14.4 vs. 24.7 days, p = 0.048). Similar, non-significant findings were noted with those with advanced fibrosis and decompensated cirrhosis. Pre-authorization requests from liver transplant clinic were found to have a faster average time-to-decision and time-to-approval than pre-authorization requests from other clinics (17.9 vs. 28.9 days, p = 0.03 & 14.8 vs. 25.6 days, p = 0.02, respectively).

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Table 5. Time-to-decision and time-to-approval in patients receiving SOF/LED therapy.

https://doi.org/10.1371/journal.pone.0135645.t005

Table 6 summarizes proportions of unapproved and initially approved for those whom pre-authorization was sent categorized by patient characteristics. A significantly higher proportion of patients with Medicare/Medicaid were initially approved compared to those with private insurance (92.2% vs. 71.4%, p = 0.002). In addition, a significantly higher proportion of patients with a viral load ≥6 million were initially approved compared to individuals with viral load < 6 million (84.1% vs. 62.5%, p = 0.04).

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Table 6. Disapproval and initial-approval rates in patients receiving SOF/LED preauthorization request.

https://doi.org/10.1371/journal.pone.0135645.t006

Univariate linear regression modeling results are shown in Table 7. Significant associations to shorter times-to-decision and times-to-approval were noted with psychiatric disease, high FIB-4 score, and pre-authorization request from transplant clinic. Also, significantly shorter times were noted with increases in total bilirubin, INR, FIB-4 score, and MELD score. Table 8 summarizes univariate logistic regression model results. This analysis revealed that having Medicare/Medicaid (OR 4.72, 95% CI 1.63–13.67) and a high viral load (OR 3.17, 1.02–9.81) were associated with higher odds of initial approval compared to private insurance and low viremia, respectively.

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Table 7. Univariate linear regression analysis with time-to-decision and time-to-approval.

https://doi.org/10.1371/journal.pone.0135645.t007

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Table 8. Univariate logistic regression analysis for initial approval.

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Multivariate linear and logistic models are shown in Tables 916. In multivariate linear models, forward stepwise addition revealed that MELD score, female gender, and advanced fibrosis were significant predictors of a shorter time-to-decision and time-to-approval, while psychiatric disease was found to be a significant predictor of a shorter time-to-approval. These associations were persistent after controlling for age and race (Tables 1214). Forward stepwise selection logistic regression modeling revealed that having Medicare/Medicaid (OR 5.96, 95% CI 1.66–21.48) and viral load ≥6 million IU/mL (OR 4.54, 95% CI 1.08–19.08) were significant predictors of initial approval and persisted after controlling for age, gender, race, presence of cirrhosis or hypertension, and pre-authorization request from transplant clinic (Tables 15 and 16).

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Table 9. Multivariate analyses for time-to-decision (n = 123).

Stepwise linear regression model for time-to-decision.

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Table 10. Multivariate analyses for time-to-decision (n = 123).

Prediction of time-to-decision based on linear multivariate model with selected variables (from stepwise selection as above) and demographic covariates (n = 123).

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Table 11. Multivariate analyses for time-to-decision (n = 123).

Prediction of time-to-decision based on linear multivariate model with selected variables (from stepwise selection as above) and demographic covariates (n = 123).

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Table 12. Multivariate model for time-to-approval (n = 117).

Models included in final model after stepwise linear regression modeling.

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Table 13. Multivariate model for time-to-approval (n = 117).

Prediction of time-to-approval based on linear multivariate model with selected variables (from stepwise selection as above) and demographic covariates (n = 117).

https://doi.org/10.1371/journal.pone.0135645.t013

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Table 14. Multivariate model for time-to-approval (n = 117).

Prediction of time-to-approval based on linear multivariate model with selected variables (from stepwise selection as above) and demographic covariates (n = 117).

https://doi.org/10.1371/journal.pone.0135645.t014

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Table 15. Multivariate Logistic Modeling for proportion initially approved, (n = 123).

Models included in final model after stepwise logistic regression modeling.

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Table 16. Multivariate Logistic Modeling for proportion initially approved, (n = 123).

Logistic model with selected variables, including other clinically-relevant covariates, in predicting initial approval (n = 123).

https://doi.org/10.1371/journal.pone.0135645.t016

Discussion

In our cohort of patients receiving pre-authorization request for SOF/LED over a three-month period, we found that nearly one in four were denied initial approval, although most patients eventually obtained drug authorization through the appeals process. Female gender, advanced Child-Pugh class, and liver transplant clinic were associated with shorter decision or approval times. Finally, having Medicare/Medicaid and a high viral load were significant predictors for initial approval, with findings persisting after controlling for demographic covariates.

The cascade of care model for HCV treatment involves numerous steps from diagnosis to successful treatment and viral eradication with patient drop-out observed at every step [11]. This analysis focused on one specific process: pre-authorization request and approval in those with a known diagnosis of HCV infection prescribed SOF/LED. Fewer than 10% patients ultimately failed to obtain access to therapy, although the appeals process led to further delay to treatment initiation. Importantly, the proportion of patients with access to drug therapy may be overestimated as this analysis was largely restricted to insured patients, all of whom had already successfully linked to specialty care in a major tertiary care university liver clinic, completed a series of pre-treatment evaluations and a formal structured HCV class, and were deemed by a specialty provider to represent an appropriate candidate with adequate motivation to initiate treatment.

The higher approval rates in patients with Medicare/Medicaid was unexpected, and could not be explained by other patient or medical variables, as this association remained significant in the multivariate model. Following Food and Drug Administration (FDA) approval of SOF/LED on October 10, 2014, updates to AASLD-IDSA HCV treatment recommendations affirmed that treatment be considered for all patients regardless of disease severity, although with the highest priority given to patients with advanced fibrosis, transplant recipients, or those with severe renal insufficiency [3]. Our hypothesis is that the higher than expected authorization rates by Medicare/Medicaid represented a time-limited anomaly driven by the absence of prior authorization guidelines until December 2014 and January 2015, through which Harvoni has been restricted by state Medicaid to patients with advanced liver fibrosis or cirrhosis (F3/F4), and selected patients at high risk for disease progression, and must be prescribed by specialty physicians [26, 27]. Restrictive prior authorization guidelines were established by many public and private payors in this state by early 2015 (Table 17). As nearly half of patients prescribed SOF/LED in this analysis had Medicare/Medicaid coverage, drug authorization rates would be expected to be lower beyond January 2015.

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Table 17. Select information requested for pre-authorization for specified insurance providers.

Exact criteria should be found in appropriate insurance pre-authorization form.

https://doi.org/10.1371/journal.pone.0135645.t017

In our cohort, patients in the liver transplant clinic were found to have shorter approval times, which may be attributable in part to overrepresentation of advanced liver disease in this population, and therefore likely be given initial approval through the pre authorization process with both public and private payors. We could not exclude the potential effect of variable access to certified specialty pharmacies with capacity to directly dispense SOF/LED medications to patients.

This is the first study to our knowledge assessing real-world access to interferon-free DAA regimens in established cohorts of patients with chronic HCV seeking antiviral therapy. These results contribute to the limited data available addressing proportion of patients successfully obtaining drug authorization through public and private insurance carriers, time to approval, and predictors for approval. Several limitations of our study warrant further investigation. We did not record data on proportion of treatment-eligible patients seeking treatment who declined to pursue SOF/LED prescription due to absence of insurance coverage, or perception of difficulty in accessing treatment due to mild liver fibrosis or other factors. Although the analysis was performed for consecutive unselected patients prescribed SOF/LED, this cohort represented a subset of patients who were deemed to be excellent candidates for treatment, and therefore selection bias by prescribing providers for individuals with anticipated approval could not be excluded. This study is also limited to authorization data in Connecticut, and state Medicaid and Medicare approval rates likely differ by states as well. Furthermore this study is focused exclusively on SOF/LED, and authorization results may be different for other FDA-approved interferon-free regimens such as sofosbuvir/simeprevir and paritaprevir/ritonavir, ombitasvir, dasabuvir, and ribavirin. Future studies are needed to clarify the variance in public and private insurance access to HCV regimens across states, stratified by liver fibrosis and other patient characteristics, the outcome of appeal requests, and approval of requests which are beyond FDA label or AASLD/IDSA recommendations.

In conclusion, we found that most patients filing a pre-authorization request for SOF/LED are eventually approved, but nearly 1 in 4 were denied access upon initial request, which may represent a barrier within the HCV care cascade. On multivariate analysis, advanced liver disease was associated with faster approval time, while Medicare/Medicaid and high viremia were associated with insurance approval. Further studies are warranted to investigate the impact of evolving drug authorization policies by Medicare/Medicaid and private payers on access to curative HCV therapies such as SOF/LED.

Supporting Information

Author Contributions

Conceived and designed the experiments: JL AD YM AL. Performed the experiments: JL AD YM AL HC CB JW EC CE KD. Analyzed the data: JL AD MC YD. Wrote the paper: JL AD YM AL EC HC CB DS JW CE KD MC YD.

References

  1. 1. Rose L, Bias TE, Mathias CB, Trooskin SB, Fong JJ. Sofosbuvir: A Nucleotide NS5B Inhibitor for the Treatment of Chronic Hepatitis C Infection. Ann Pharmacother. 2014;48(8):1019–29. pmid:24811396
  2. 2. Pockros PJ. Advances in newly developing therapy for chronic hepatitis C virus infection. Front Med. 2014;8(2):166–74. pmid:24871445
  3. 3. AASLD/IDSA/IAS–USA. Recommendations for testing, managing, and treating hepatitis C [updated December 19, 2014]. Available: http://www.hcvguidelines.org/.
  4. 4. Schinazi R, Halfon P, Marcellin P, Asselah T. HCV direct-acting antiviral agents: the best interferon-free combinations. Liver Int. 2014;34 Suppl 1:69–78. pmid:24373081
  5. 5. Afdhal N, Reddy KR, Nelson DR, Lawitz E, Gordon SC, Schiff E, et al. Ledipasvir and sofosbuvir for previously treated HCV genotype 1 infection. N Engl J Med. 2014;370(16):1483–93. pmid:24725238
  6. 6. Afdhal N, Zeuzem S, Kwo P, Chojkier M, Gitlin N, Puoti M, et al. Ledipasvir and sofosbuvir for untreated HCV genotype 1 infection. N Engl J Med. 2014;370(20):1889–98. pmid:24725239
  7. 7. Kowdley KV, Gordon SC, Reddy KR, Rossaro L, Bernstein DE, Lawitz E, et al. Ledipasvir and sofosbuvir for 8 or 12 weeks for chronic HCV without cirrhosis. N Engl J Med. 2014;370(20):1879–88. pmid:24720702
  8. 8. Kohli A, Osinusi A, Sims Z, Nelson A, Meissner EG, Barrett LL, et al. Virological response after 6 week triple-drug regimens for hepatitis C: a proof-of-concept phase 2A cohort study. Lancet. 2015;385(9973):1107–13. pmid:25591505
  9. 9. Institute of Medicine. Hepatitis and Liver Cancer: A National Strategy for Prevention and Control of Hepatitis B and C. Colvin HM, Mitchell AE, editors. Washington (DC): The National Academies Press; 2010.
  10. 10. Yehia BR, Schranz AJ, Umscheid CA, Lo Re V 3rd. The treatment cascade for chronic hepatitis C virus infection in the United States: a systematic review and meta-analysis. PloS one. 2014;9(7):e101554. pmid:24988388
  11. 11. Linas BP, Barter DM, Leff JA, Assoumou SA, Salomon JA, Weinstein MC, et al. The hepatitis C cascade of care: identifying priorities to improve clinical outcomes. PloS one. 2014;9(5):e97317. pmid:24842841
  12. 12. Gardner EM, McLees MP, Steiner JF, Del Rio C, Burman WJ. The spectrum of engagement in HIV care and its relevance to test-and-treat strategies for prevention of HIV infection. Clinical infectious diseases: an official publication of the Infectious Diseases Society of America. 2011;52(6):793–800.
  13. 13. Mugavero MJ, Amico KR, Horn T, Thompson MA. The state of engagement in HIV care in the United States: from cascade to continuum to control. Clinical infectious diseases: an official publication of the Infectious Diseases Society of America. 2013;57(8):1164–71.
  14. 14. Volk ML, Tocco R, Saini S, Lok AS. Public health impact of antiviral therapy for hepatitis C in the United States. Hepatology. 2009;50(6):1750–5. pmid:19824079
  15. 15. Hallett TB, Eaton JW. A side door into care cascade for HIV-infected patients? Journal of acquired immune deficiency syndromes. 2013;63 Suppl 2:S228–32. pmid:23764640
  16. 16. Klein SJ, Wright LN, Birkhead GS, Mojica BA, Klopf LC, Klein LA, et al. Promoting HCV treatment completion for prison inmates: New York State's hepatitis C continuity program. Public health reports. 2007;122 Suppl 2:83–8. pmid:17542460
  17. 17. Mehta SH, Lucas GM, Mirel LB, Torbenson M, Higgins Y, Moore RD, et al. Limited effectiveness of antiviral treatment for hepatitis C in an urban HIV clinic. Aids. 2006;20(18):2361–9. pmid:17117023
  18. 18. Ditah I, Al Bawardy B, Gonzalez HC, Saberi B, Ditah C, Kamath PS, et al. Lack of Health Insurance Limits the Benefits of Hepatitis C Virus Screening: Insights from the National Health and Nutrition Examination Hepatitis C Follow-Up Study. Am J Gastroenterol. 2015.
  19. 19. Mehta SH, Genberg BL, Astemborski J, Kavasery R, Kirk GD, Vlahov D, et al. Limited uptake of hepatitis C treatment among injection drug users. J Community Health. 2008;33(3):126–33. pmid:18165889
  20. 20. Oramasionwu CU, Moore HN, Toliver JC. Barriers to hepatitis C antiviral therapy in HIV/HCV co-infected patients in the United States: a review. AIDS patient care and STDs. 2014;28(5):228–39. pmid:24738846
  21. 21. Lawitz EJ, Membreno FE. Response-guided therapy in patients with genotype 1 hepatitis C virus: current status and future prospects. J Gastroenterol Hepatol. 2014;29(8):1574–81. pmid:24852401
  22. 22. Borgia SM, Rowaiye A. Increased eligibility for treatment of chronic hepatitis C infection with shortened duration of therapy: Implications for access to care and elimination strategies in Canada. Can J Gastroenterol Hepatol. 2015;29(3):125–9. pmid:25855874
  23. 23. Hepatitis C Online: Ledipasvir-Sofosbuvir 2014 [cited 2015 April 11th]. Available: http://www.hepatitisc.uw.edu/page/treatment/drugs/ledipasvir-sofosbuvir.
  24. 24. Anthem: Harvoni Prior Authorization Approval Criteria 2014 [updated October 15th, 2014; cited 2015 April 11th]. Available: http://www.anthem.com/provider/noapplication/f0/s0/t0/pw_e225443.pdf?na=pharminfo.
  25. 25. Sterling RK, Lissen E, Clumeck N, Sola R, Correa MC, Montaner J, et al. Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection. Hepatology. 2006;43(6):1317–25. pmid:16729309
  26. 26. Connecticut department of social services: Medical Assistance Program. "New hepatitis C prior authorization criteria—Sovaldi" [updated November 2014]. Available: http://www.huskyhealthct.org/providers/provider_postings/New_Hepatitis_C_Prior_Authorization_Criteria-Sovaldi.pdf.
  27. 27. Connecticut medical assistance program hepatitis C prior authorization (PA) request form- Sovaldi (sofosbuvir) [updated January 2015]. Available: https://www.ctdssmap.com/CTPortal/Pharmacy%20Information/tabId/65/~Information/Get%20Download%20File/tabid/44//Default.aspx?Filename=Sovaldi%20PA%20Request%20Form.pdf&URI=Forms/Sovaldi%20PA%20Request%20Form.pdf.