A recent study by researchers at the University of California, Los Angeles, found high rates of mortality and morbidity in patients with opioid use disorder (OUD) in a large healthcare system. Their findings were reported online in the Journal of Addiction Medicine.¹

In 2014, there were more than 28,000 opioid-related deaths in the United States — a record high.² The growing opioid epidemic has accelerated efforts to identify associated risk factors and potential solutions. A substantial body of research has linked OUD with increased morbidity and mortality.

A 2015 study on 32,322 patients receiving treatment for OUD found the mortality risk to be 4-fold higher in that patient group than in the general population.³This risk decreased to 1.8-fold when patients were in methadone maintenance treatment, and increased to 6.1-fold when they were not in treatment. The main cause of death was related to drugs or alcohol (43.6%).

OUD treatment in the United States has primarily been offered in addiction treatment centers rather than in general healthcare settings. Despite the clear need for primary care physicians to address the OUD crisis, they may not feel confident in their ability or resources to treat patients with substance use disorders (SUDs).⁴ While there have been increased efforts to educate clinicians, “many do not fully appreciate the mortality risks to their patients,” and “information on the rates and causes of mortality among OUD patients in the general healthcare system is lacking,” wrote the researchers in the current study.

They examined medical records and national mortality data from 2576 adult patients with OUD in a large healthcare system to determine all-cause and cause-specific mortality rates in OUD patients vs the general population. Over a mean period of 3.7 person-years, there were 465 confirmed deaths (18.1% of the total sample), which corresponded to a crude mortality rate of 48.6 per 1000 person-years and a standardized mortality ratio of 10.3 (95% CI, 9.4–11.3).

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The results further reveal the following observations:

The top causes of death were drug overdose and disorder (19.8%), cardiovascular disease (17.4%), cancer (16.8%), and infectious disease (13.5%, including 12% hepatitis C virus [HCV])
Two clinically important indicators of overall mortality risk were HCV (hazard ratio [HR] 1.99; 95% CI, 1.62-2.46) and alcohol use disorder (HR 1.27; 95% CI, 1.05-1.55)
Tobacco use disorder (adjusted HR [AHR] 2.58; 95% CI, 1.60-4.17) was associated with an elevated risk for cardiovascular death
HCV infection (AHR 2.55; 95% CI, 1.52-4.26) was linked with cancer mortality risk
HCV (AHR 1.92; 95% CI, 1.03-3.60) and alcohol use disorder (AHR 5.44; 95% CI, 2.95-10.05) were associated with liver-related mortality risk

The mortality rates in this general healthcare setting were significantly higher than the rates seen in an SUD treatment system. “The alarmingly high morbidity and mortality among OUD patients revealed in the present study challenge healthcare systems to find new and innovative ways to expand evidence-based strategies for OUD in a variety of settings,” the researchers wrote. “Given the chronic, relapsing nature of OUD, and high medical and psychiatric comorbidity, continued care encompassing screening, early intervention, support, and monitoring is essential.”

Summary and Clinical Applicability

High rates of morbidity and mortality were observed in patients with OUD in a general healthcare setting, underscoring the need for adequate screening and treatment strategies by primary care physicians.

Limitations and Disclosures

The generalizability of these findings may be limited by the nature of the sample: predominantly white patients receiving treatment within a single health system in a specific area of the United States. In addition, the results depend on the accuracy and validity of the electronic healthcare record data.

Dr Saxon discloses the receipt of royalties as an editor for UpToDate. The remaining authors report relevant conflicts.

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