Natasha K. Martin
University of California, San Diego
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Featured researches published by Natasha K. Martin.
The Lancet | 2016
Jeffrey D. Stanaway; Abraham D. Flaxman; Mohsen Naghavi; Christina Fitzmaurice; Theo Vos; Ibrahim Abubakar; Laith J. Abu-Raddad; Reza Assadi; Neeraj Bhala; Benjamin C. Cowie; Mohammad H. Forouzanfour; Justina Groeger; Khayriyyah Mohd Hanafiah; Kathryn H. Jacobsen; Spencer L. James; Jennifer H. MacLachlan; Reza Malekzadeh; Natasha K. Martin; Ali A. Mokdad; Ali H. Mokdad; Christopher J L Murray; Dietrich Plass; Saleem M. Rana; David B. Rein; Jan Hendrik Richardus; Juan R. Sanabria; Mete I Saylan; Saeid Shahraz; Samuel So; Vasiliy Victorovich Vlassov
BACKGROUND With recent improvements in vaccines and treatments against viral hepatitis, an improved understanding of the burden of viral hepatitis is needed to inform global intervention strategies. We used data from the Global Burden of Disease (GBD) Study to estimate morbidity and mortality for acute viral hepatitis, and for cirrhosis and liver cancer caused by viral hepatitis, by age, sex, and country from 1990 to 2013. METHODS We estimated mortality using natural history models for acute hepatitis infections and GBDs cause-of-death ensemble model for cirrhosis and liver cancer. We used meta-regression to estimate total cirrhosis and total liver cancer prevalence, as well as the proportion of cirrhosis and liver cancer attributable to each cause. We then estimated cause-specific prevalence as the product of the total prevalence and the proportion attributable to a specific cause. Disability-adjusted life-years (DALYs) were calculated as the sum of years of life lost (YLLs) and years lived with disability (YLDs). FINDINGS Between 1990 and 2013, global viral hepatitis deaths increased from 0·89 million (95% uncertainty interval [UI] 0·86-0·94) to 1·45 million (1·38-1·54); YLLs from 31·0 million (29·6-32·6) to 41·6 million (39·1-44·7); YLDs from 0·65 million (0·45-0·89) to 0·87 million (0·61-1·18); and DALYs from 31·7 million (30·2-33·3) to 42·5 million (39·9-45·6). In 2013, viral hepatitis was the seventh (95% UI seventh to eighth) leading cause of death worldwide, compared with tenth (tenth to 12th) in 1990. INTERPRETATION Viral hepatitis is a leading cause of death and disability worldwide. Unlike most communicable diseases, the absolute burden and relative rank of viral hepatitis increased between 1990 and 2013. The enormous health loss attributable to viral hepatitis, and the availability of effective vaccines and treatments, suggests an important opportunity to improve public health. FUNDING Bill & Melinda Gates Foundation.
Hepatology | 2013
Natasha K. Martin; Peter Vickerman; Jason Grebely; Margaret Hellard; Sharon J. Hutchinson; Viviane D. Lima; Graham R. Foster; John F. Dillon; David J. Goldberg; Gregory J. Dore; Matthew Hickman
Substantial reductions in hepatitis C virus (HCV) prevalence among people who inject drugs (PWID) cannot be achieved by harm reduction interventions such as needle exchange and opiate substitution therapy (OST) alone. Current HCV treatment is arduous and uptake is low, but new highly effective and tolerable interferon‐free direct‐acting antiviral (DAA) treatments could facilitate increased uptake. We projected the potential impact of DAA treatments on PWID HCV prevalence in three settings. A dynamic HCV transmission model was parameterized to three chronic HCV prevalence settings: Edinburgh, UK (25%); Melbourne, Australia (50%); and Vancouver, Canada (65%). Using realistic scenarios of future DAAs (90% sustained viral response, 12 weeks duration, available 2015), we projected the treatment rates required to reduce chronic HCV prevalence by half or three‐quarters within 15 years. Current HCV treatment rates may have a minimal impact on prevalence in Melbourne and Vancouver (<2% relative reductions) but could reduce prevalence by 26% in 15 years in Edinburgh. Prevalence could halve within 15 years with treatment scale‐up to 15, 40, or 76 per 1,000 PWID annually in Edinburgh, Melbourne, or Vancouver, respectively (2‐, 13‐, and 15‐fold increases, respectively). Scale‐up to 22, 54, or 98 per 1,000 PWID annually could reduce prevalence by three‐quarters within 15 years. Less impact occurs with delayed scale‐up, higher baseline prevalence, or shorter average injecting duration. Results are insensitive to risk heterogeneity or restricting treatment to PWID on OST. At existing HCV drug costs, halving chronic prevalence would require annual treatment budgets of US
Archive | 2013
Natasha K. Martin; Peter Vickerman; Jason Grebely; Margaret Hellard; Sharon J. Hutchinson; Viviane D. Lima; Graham R. Foster; John F. Dillon; David J. Goldberg; Gregory J. Dore; Matthew Hickman
3.2 million in Edinburgh and approximately
The Lancet | 2014
Roger Williams; R Aspinall; Mark A Bellis; Ginette Camps-Walsh; Matthew E. Cramp; Anil Dhawan; James Ferguson; Dan Forton; Graham R. Foster; Sir Ian Gilmore; Matthew Hickman; Mark Hudson; Deirdre Kelly; Andrew Langford; Martin Lombard; Louise Longworth; Natasha K. Martin; Kieran Moriarty; Philip N. Newsome; John O'Grady; Rachel Pryke; Harry Rutter; Stephen D. Ryder; Nick Sheron; Thomas Smith
50 million in Melbourne and Vancouver. Conclusion: Interferon‐free DAAs could enable increased HCV treatment uptake among PWID, which could have a major preventative impact. However, treatment costs may limit scale‐up, and should be addressed. (Hepatology 2013;58:1598–1609)
BMJ | 2012
Georgie J. MacArthur; Silvia Minozzi; Natasha K. Martin; Peter Vickerman; Sherry Deren; Julie Bruneau; Louisa Degenhardt; Matthew Hickman
Substantial reductions in hepatitis C virus (HCV) prevalence among people who inject drugs (PWID) cannot be achieved by harm reduction interventions such as needle exchange and opiate substitution therapy (OST) alone. Current HCV treatment is arduous and uptake is low, but new highly effective and tolerable interferon‐free direct‐acting antiviral (DAA) treatments could facilitate increased uptake. We projected the potential impact of DAA treatments on PWID HCV prevalence in three settings. A dynamic HCV transmission model was parameterized to three chronic HCV prevalence settings: Edinburgh, UK (25%); Melbourne, Australia (50%); and Vancouver, Canada (65%). Using realistic scenarios of future DAAs (90% sustained viral response, 12 weeks duration, available 2015), we projected the treatment rates required to reduce chronic HCV prevalence by half or three‐quarters within 15 years. Current HCV treatment rates may have a minimal impact on prevalence in Melbourne and Vancouver (<2% relative reductions) but could reduce prevalence by 26% in 15 years in Edinburgh. Prevalence could halve within 15 years with treatment scale‐up to 15, 40, or 76 per 1,000 PWID annually in Edinburgh, Melbourne, or Vancouver, respectively (2‐, 13‐, and 15‐fold increases, respectively). Scale‐up to 22, 54, or 98 per 1,000 PWID annually could reduce prevalence by three‐quarters within 15 years. Less impact occurs with delayed scale‐up, higher baseline prevalence, or shorter average injecting duration. Results are insensitive to risk heterogeneity or restricting treatment to PWID on OST. At existing HCV drug costs, halving chronic prevalence would require annual treatment budgets of US
Journal of Hepatology | 2011
Natasha K. Martin; Peter Vickerman; Graham R. Foster; Sharon J. Hutchinson; David J. Goldberg; Matthew Hickman
3.2 million in Edinburgh and approximately
Hepatology | 2012
Natasha K. Martin; Peter Vickerman; Alec Miners; Graham R. Foster; Sharon J. Hutchinson; David J. Goldberg; Matthew Hickman
50 million in Melbourne and Vancouver. Conclusion: Interferon‐free DAAs could enable increased HCV treatment uptake among PWID, which could have a major preventative impact. However, treatment costs may limit scale‐up, and should be addressed. (Hepatology 2013;58:1598–1609)
Clinical Infectious Diseases | 2013
Natasha K. Martin; Matthew Hickman; Sharon J. Hutchinson; David J. Goldberg; Peter Vickerman
Liver disease in the UK stands out as the one glaring exception to the vast improvements made during the past 30 years in health and life expectancy for chronic disorders such as stroke, heart disease, and many cancers. Mortality rates have increased 400% since 1970, and in people younger than 65 years have risen by almost five-times. Liver disease constitutes the third commonest cause of premature death in the UK and the rate of increase of liver disease is substantially higher in the UK than other countries in western Europe. More than 1 million admissions to hospital per year are the result of alcohol-related disorders, and both the number of admissions and the increase in mortality closely parallel the rise in alcohol consumption in the UK during the past three decades. The aim of this Commission is to provide the strongest evidence base through involvement of experts from a wide cross-section of disciplines, making firm recommendations to reduce the unacceptable premature mortality and disease burden from avoidable causes and to improve the standard of care for patients with liver disease in hospital. From the substantial number of recommendations given in our Commission, we selected those that will have the greatest effect and that need urgent implementation. Although the recommendations are based mostly on data from England, they have wider application to the UK as a whole, and are in accord with the present strategy for health-care policy by the Scottish Health Boards, the Health Department of Wales, and the Department of Health and Social Services in Northern Ireland.
The Lancet Global Health | 2014
Jeffrey W. Eaton; Nicolas A. Menzies; John Stover; Valentina Cambiano; Leonid Chindelevitch; Anne Cori; Jan A.C. Hontelez; Salal Humair; Cliff C. Kerr; Daniel J. Klein; Sharmistha Mishra; Kate M. Mitchell; Brooke E. Nichols; Peter Vickerman; Roel Bakker; Till Bärnighausen; Anna Bershteyn; David E. Bloom; Marie-Claude Boily; Stewart T. Chang; Ted Cohen; Peter J. Dodd; Christophe Fraser; Chaitra Gopalappa; Jens D. Lundgren; Natasha K. Martin; Evelinn Mikkelsen; Elisa Mountain; Quang D. Pham; Michael Pickles
Objective To quantify the effect of opiate substitution treatment in relation to HIV transmission among people who inject drugs. Design Systematic review and meta-analysis of prospective published and unpublished observational studies. Data sources Search of Medline, Embase, PsychINFO, and the Cochrane Library from the earliest year to 2011 without language restriction. Review methods We selected studies that directly assessed the impact of opiate substitution treatment in relation to incidence of HIV and studies that assessed incidence of HIV in people who inject drugs and that might have collected data regarding exposure to opiate substitution treatment but not have reported it. Authors of these studies were contacted. Data were extracted by two reviewers and pooled in a meta-analysis with a random effects model. Results Twelve published studies that examined the impact of opiate substitution treatment on HIV transmission met criteria for inclusion, and unpublished data were obtained from three additional studies. All included studies examined methadone maintenance treatment. Data from nine of these studies could be pooled, including 819 incident HIV infections over 23 608 person years of follow-up. Opiate substitution treatment was associated with a 54% reduction in risk of HIV infection among people who inject drugs (rate ratio 0.46, 95% confidence interval 0.32 to 0.67; P<0.001). There was evidence of heterogeneity between studies (I2=60%, χ2=20.12, P=0.010), which could not be explained by geographical region, site of recruitment, or the provision of incentives. There was weak evidence for greater benefit associated with longer duration of exposure to opiate substitution treatment. Conclusion Opiate substitution treatment provided as maintenance therapy is associated with a reduction in the risk of HIV infection among people who inject drugs. These findings, however, could reflect comparatively high levels of motivation to change behaviour and reduce injecting risk behaviour among people who inject drugs who are receiving opiate substitution treatment.
AIDS | 2013
Thomas C.S. Martin; Natasha K. Martin; Matthew Hickman; Peter Vickerman; Emma Page; Rhiannon Everett; Brian Gazzard; Mark Nelson
BACKGROUND & AIMS Hepatitis C virus antiviral treatment is effective for individual patients but few active injecting drug users are treated. We considered the utility of antiviral treatment for primary prevention of hepatitis C. METHODS A hepatitis C transmission model among injecting drug users was developed, incorporating treatment (62.5% average sustained viral response) with no retreatment after initial treatment failure, potential re-infection for those cured, equal genotype setting (genotype 1:genotype 2/3), and no immunity. In addition, we examined scenarios with varied treatment response rates, immunity, or retreatment of treatment failures. RESULTS In the baseline scenario, annually treating 10 infections per 1000 injecting drug users results in a relative decrease in hepatitis C prevalence over 10 years of 31%, 13%, or 7% for baseline (untreated endemic chronic infection) prevalences of 20%, 40%, or 60%, respectively. Sensitivity analyses show that including the potential for immunity has minimal effect on the predictions; prevalence reductions remain even if SVR is assumed to be 25% lower among active IDU than current evidence suggests; retreatment of treatment failures does not alter the short-term (<5 years) projections, but does increase treatment gains within 20 years; hepatitis C free life years gained from treating active injecting drug users are projected to be higher than from treating non-injecting drug users for prevalences below 60%. CONCLUSIONS Despite the possibility of re-infection, modest rates of hepatitis C treatment among active injecting drug users could effectively reduce transmission. Evaluating and extending strategies to treat hepatitis C among active injectors are warranted.