Long-Term Prescription Opioid Use Linked to Higher Risk of Hepatitis C

James Wilton, MPH

Prescription opioid use is associated with a significant risk of hepatitis C virus (HCV) seroconversion, according to new research.

A team, led by James Wilton, MPH, British Columbia Centre for Disease Control, assessed the link between medically dispensed long-term prescription opioid therapy for noncancer pain and HCV seroconversion among individuals who were initially injection drug use-naïve.

The Risk of HCV

The initiation of injection drugs occurs more frequently among individuals prescribed opioid therapies for noncancer pain. This could potentially increase the spread of HCV.

In the population-based, retrospective cohort, the investigators examined 382,478 individuals tested for hepatitis C in British Columbia with linkage to outpatient pharmacy dispensations.

The majority of participants were female (n = 224,373; 58.7%), born before 1974 (n = 201,944; 52.8%), and younger than 35 at baseline (n = 196,298; 53.9%).

Each participant had an initial negative test result for HCV followed by 1 additional test between 2000-2017. The patients also had no history of substance use at baseline and were followed up with for 2,057,668 person-years.

Each individual was followed up with from baseline to the last HCV-negative test or the estimated date of seroconversion.

Exposures included episodes of prescription opioid use for noncancer pain, defined as acute or long-term. The investigators also treated prescription opioid exposure status as time-varying in the survival analyses.

In the secondary analyses, the investigators stratified long-term exposure by intensity of use and by average daily dose in morphine equivalents (MEQ).

The investigators sought main outcomes of the association between time-varying prescription opioid status and HCV seroconversion, which was assessed using multivariable Cox regression models.

Analyzing Opioid Use

There was a total of 1947 HCV seroconversions, with 41,755 participants (10.9%) exposed to long-term prescription opioid therapy at baseline or during follow-up. In addition, the HCV seroconversion rate per 1000 person-years was 0.8 among participants who were prescription opioid-naïve/acute (n = 1489; 76.5% seroconversions; 0.4% seroconverted within 5 years).

This rate increased to 2.1 with long-term prescription opioid therapy (n = 458; 23.5% seroconversions; 1.1% seroconverted within 5 years).

Using the multivariable analysis, the team found exposure to long-term prescription opioid therapy was linked to a 3.2-fold (95% CI, 2.9-3.6) higher risk of HCV seroconversion compared to prescription opioid-naïve or acute.

Separately in the Cox models, the investigators found long-term chronic use was associated with a 4.7-fold higher risk of HCV seroconversion compared to naïve or acute use (95% CI, 3.9-5.8).

In addition, long-term higher-dose use of at least 90 MEQ was linked to a 5.1-fold higher risk compared to naïve or acute use (95% CI, 3.7-7.1).

“In this cohort study of people with more than 1 HCV test, long-term prescription opioid therapy for noncancer pain was associated with a higher risk of HCV seroconversion among individuals who were injection drug use–naive at baseline or at prescription opioid initiation,” the authors wrote. “These results suggest injection drug use initiation risk is higher among people dispensed long-term therapy and may be useful for informing approaches to identify and prevent HCV infection.”

However, the investigators said the results should not justify abrupt discontinuation of long-term therapy.

The study, “Association Between Prescription Opioid Therapy for Noncancer Pain and Hepatitis C Virus Seroconversion,” was published online in JAMA Network Open.