The Centers for Disease Control and Prevention (CDC) has drawn concerning links between the opioid epidemic and fast-increasing rates of hepatitis C virus (HCV) among pregnant women.

Publishing their findings in Morbidity and Mortality Weekly Report, CDC investigators led by Jean Y. Ko, PhD, analyzed hospital discharge data from the Healthcare Cost and Utilization Project, in particular its National Inpatient Sample (NIS), covering 2000 to 2015. The NIS is the largest publicly available in-patient heath care database in the United States that includes individuals receiving health coverage from all types of insurers.

The researchers relied on the ICD-9-CM diagnostic codes in their investigation. Because of a recent switchover to the updated ICD-10-CM codes in U.S. health care practices, this study did not include the fifth quarter of 2015 or any more recent periods.

Between 2000 and 2015, the rate of HCV infection among mothers per 1,000 infant deliveries increased 5.1-fold, from 0.8 to 4.1 deliveries. The increase was statistically significant, meaning the shift is unlikely to have been driven by chance, between 2000 and 2004 (a 15.7% increase), 2004 to 2010 (a 6.1% increase) and 2010 to the third quarter of 2015 (a 14.9% increase).

Among deliveries in which the mother was diagnosed with opioid use disorder (OUD), the women’s hep C infection rate per 1,000 deliveries increased 2.5-fold, from 87.4 to 216.9 diagnoses, during the overall study period. This group’s diagnosis rate increased significantly, by 17.2%, between 2000 and 2004, remained statistically stable between 2004 and 2011 and increased significantly, by 7.9%, between 2011 and 2015.

As for deliveries in which the mothers were not diagnosed with OUD, the rate of HCV diagnosis per 1,000 deliveries was much lower: 0.7 in 2000 and increased by 3.7-fold, to 2.6, in 2015. The diagnosis rate was statistically stable between 2000 and 2002 and increased significantly by 5.5% between 2002 and 2011 and by 15.0% between 2011 and 2015.

The study authors broke down the degree to which certain factors were associated with an increased likelihood of women having HCV alone, OUD alone or both HCV and OUD, as opposed to having neither the virus nor OUD.

Compared with being at least 35 years old, being between 25 to 34 years old was associated with a 1.2-fold, 1.8-fold and 1.8-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively. Being younger than 25 years old was associated with a respective 1.6-fold and 1.4-fold increased likelihood of having OUD only and having HCV plus OUD.

Compared with having private insurance, having a public form of coverage, including Medicare and Medicaid, was associated with a 5.5-fold, 6.4-fold and 9.9-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively.

Compared with being Black, being white was associated with a 3.6-fold, 3.7-fold and 10.9-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively; being Native American was associated with a 5.0-fold, 5.9-fold and 8.0-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively; and being Asian or Pacific Islander was associated with a 40% reduced likelihood of having OUD only.

Compared with living in a ZIP code in which the median household income was at least $68,000, living in a ZIP code with a median income of $52,000 to $67,999 was associated with a 1.4-fold, 1.5-fold and 1.5-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively; living in a ZIP code with a median income of $42,000 to $51,999 was associated with a 2.1-fold, 1.8-fold and 1.9-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively; and living in a ZIP code with a median income no greater than $41,999 was associated with a 2.5-fold, 2.0-fold and 2.5-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively.

Finally, compared with living in the West, living in the Northeast was associated with a 1.3-fold, 2.0-fold and 4.8-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively; living in the South was associated with a 1.9-fold, 1.3-fold and 2.8-fold increased likelihood of having HCV only, OUD only and HCV plus OUD, respectively; and living in the Midwest was associated with a 1.4-fold and 2.7-fold increased likelihood of having OUD only and HCV plus OUD, respectively.

“Treatment of opioid use disorder should include screening and referral for related conditions such as HCV infection,” the study authors concluded.

To read the CDC report, click here.