Much attention has been focused on the opioid epidemic and the risk of death associated with these drugs. However, this class of medications is associated with other serious adverse events including gastrointestinal (GI) complications, cardiac events, infections, and falls and fracture, which are all particularly problematic in the vulnerable older adult breast cancer (BC) survivor population.

A retrospective cohort study examined the risk of opioid-related serious adverse drug events (ADEs) among older female breast cancer survivors. Using data from 2007 to 2016 from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Medicare Linked Database, which is a population-based cancer registry that includes 28% of U.S. population, investigators estimated the immediate risk of opioid-related ADEs associated with time-dependent daily opioid exposure in the year after active BC treatment.

To be eligible for inclusion in the study, women aged 66 to 90 years had to be diagnosed with an initial cancer, which had to be a stage 0 to III primary BC, between January 1, 2008 and December 31, 2015. Women also had to be enrolled in Medicare Parts A and B for 12 months prior to and for 12 months following their BC treatment and in Medicare Part D for 3 months prior and 12 months after their BC treatment. Exclusion criteria included those who had died, had developed a second cancer within the 12 months of follow-up, did not complete 12 months of follow-up prior to December 31, 2016, or had had an opioid prescription filled 3 months before their BC diagnosis.

Outcome measures included time-dependent daily binary measures to indicate the occurrence of a serious opioid-related ADE on a given day within the 12-month follow-up period. These outcome measures included both substance misuse (defined as opioid dependence, abuse, or poisoning) as well as serious infection, GI events, falls and fractures, cardiovascular events, and all-cause hospitalization. Medicare Part D data were used to determine daily exposure versus no exposure to prescription opioids during the study period.

The study included 38,310 women with a mean age of 74.3 years. There were 0.237 (CI, 0.229-0.245) ADEs associated with opioid use per 1,000 person-days that were not related to opioid misuse. The overall risk of opioid misuse was low at 0.010 (CI, 0.008-0.011) ADEs related to substance use per 1,000 person-days. Overall, ADEs associated with opioid use were 23.7-fold more common than that of opioid misuse. However, opioid exposure was associated with a 14.62 higher immediate risk of ADEs related to substance misuse. Current opioid exposure was associated with a 2.5-fold higher increase of a serious ADE that was not related to substance misuse and a 2.77-fold increase in the immediate risk of all-cause hospitalization. Overall, there were 0.675 (CI, 0.662-0.689) all-cause hospitalizations per 1,000 person-days with a 2.77-fold increase in the immediate risk of all-cause hospitalization.

Other significant findings associated with opioid exposure included a two- to threefold increase in the immediate risk of other ADEs related to opioid use but not misuse. Among these were a 2.87-fold increase in an adverse GI event, a 2.34-fold increase in falls and fracture risk, a 2.38-fold increase in the risk of a cardiovascular event, and a 3.26-fold increase in the risk of serious infection. A dose-response relationship was found between opioid use and the risk of serious ADEs with risk increased 3.4-fold in those with a current opioid supply of >50 morphine-equivalent doses and 2.3-fold higher in those receiving 1 to 49 morphine milligram equivalents.

As opioid stewards, pharmacists can play an active role in minimizing unnecessary long-term opioid therapy by encouraging prescriber adherence to CDC guidelines, which recommend limiting the dose and duration of opioid therapy and by encouraging patients to discard unused opioid medication.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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