Global Burden of Hepatitis, HIV Linked to Injection Drug Use

Preventive interventions and treatment efforts must be prioritized to lessen the global burden of human immunodeficiency virus (HIV), hepatitis B (HBV), and hepatitis C (HCV) as a result of injection drug use, according to research published in Lancet Infectious Diseases.

Louisa Degenhardt, PhD, of the National Drug and Alcohol Research Center at the University of South Wales in Sydney, Australia, and colleagues used the Global Burden of Disease (GBD) study to measure the burden of HBV and HCV—including cirrhosis and liver cancer—and HIV at the country, regional, and global level between 1990 and 2013. The researchers used Cause of Death Ensemble modeling (CODEm) and a disease epidemiology modeling (DisMod-MR 2.0) to model morbidity and mortality among injection drug users. Additionally, a cohort method was used to recalibrate individuals’ accumulated risk of HBV and HCV based on injection drug use history.

Primary outcomes were estimates of disease burden through years of life lost (YLL), years of life lived with disability (YLD) deaths, and disability-adjusted life-years (DALYs).

The researchers noted that on a global level, the number of DALYs attributable to injection drug use for HIV, HBV, and HCV quadrupled between 1990 and 2013, from 2.6 million to 10 million. Viral hepatitis as a result of injection drug use was a larger contributor to disease burden than HIV, while HCV was the largest contributor by what the researchers found was a “substantial margin.” HCV burden accounted for 7.05 million DALYs (95% uncertainty interval [UI] 5.88 million-8.15 million) in 2013. Nearly all HCV-related burden was linked to liver cirrhosis (3.85 million DALYs, 95% UI 2.49 million-3.84 million); comparative HIV and HBV burdens were 2.82 million DALYs (95% UI 2.39 million-3.81 million) and  0.22 million DALYs (95% UI 0.10 million-0.34 million), respectively. Most disease burden was due to YLLs, rather than YLDs, the researchers noted.

“We estimated that regions in Asia jointly accounted for nearly two-thirds of global HBV burden and for half of the global HCV burden attributable to injection drug use,” Dr Degenhardt and colleagues wrote.

They went on to note that in eastern Asia, the contribution to global burden was particularly high, at 44% for HBV and 34% for HCV; comparatively, sub-Saharan Africa accounted for 5% each for HBV and HCV, although global burden for HIV was 46%. North America accounts for 9% of HBV burden, 11% of HCV burden, and 2% of HIV burden, and Eastern Europe accounts for an estimated 7% of HBV burden, 9% of HCV burden, and 20% of HIV burden. Highest age-standardized DALY rates for HIV linked to injection drug use were in Eastern Europe and sub-Saharan Africa.

“Globally, in 2013, more than 10 million DALYs were estimated to be attributable to previous exposure to HIV, HBV, and HCV via injection drug use,” the researchers wrote. “This represents a 4 times increase in DALYs since 1990…The majority of attributable burden was due to HCV infection and its consequences.”

Dr Degenhardt and colleagues noted that cost-effective HBV, HCV, and HIV interventions are available to reduce the global burden of these infections, and that recent development of “much more effective and less toxic drugs” to treat HCV infection should improve previous extremely low rates of HCV treatment among injection drug users.

“Barriers to treatment include low diagnosis rates, unwarranted restrictions on treatment access, and medicine costs,” the researchers concluded. “Case-finding, referral, and active management are crucial for the prevention of morbidity in people with a history of injection drug use.”

Limitations

• Limitations of the GBD study include gaps in data and variable data quality, as well as contention relating to the modeling used to generate consistent disease-specific models.
• Specific to this study, the limited amount of data on population-level injection drug use and the risk of HIV, HBV, and HCV resulted in estimation uncertainty—especially countries within Africa where limited data exist on rates of injection drug use and the prevalence of infection.

Funding for this study was provided by the Bill & Melinda Gates Foundation and the Australian National Health and Medical Research Council.

Disclosures: Dr Degenhardt reports receiving educational grants from Reckitt Benckiser, Mundipharma, and Indivior. Dr Hickman reports receiving honoraria from Jansen, Gilead, AbbVie, and MSD. Dr Strang reports receiving funding from Merck, grants and consultancy payments from Martindale Pharma, Mundipharma, and Braeburn Pharma, and a grant from the European Monitoring Center for Drugs and Drug Addiction (EMCDDA); he is also named in a patent issued to Euro-Celtique and has contributed to a patent application from King’s College London.

Reference

Degenhardt L, Charlson F, Stanaway J, et al. Estimating the burden of disease attributable to injecting drug use as a risk factor for HIV, hepatitis C, and hepatitis B: findings from the Global Burden of Disease Study 2013. Lancet Infect Dis. 2016; doi: 10.1016/S1476-3099(16)30325-5.