Dramatic Surge in Opioid Use Among Cardiac Surgery Patients

Over a 15-year period, there was a dramatic surge in the number of patients with opioid use disorder (OUD) who underwent cardiac surgery, new research reports.

Investigators analyzed data from more than 5.7 million US patients who underwent cardiac surgery and found a nine-fold increase of OUD from 1998 to 2013 among these cardiac patients.

Although mortality rates were similar among patients with and without OUD, cardiac patients with OUD had higher rates of blood transfusions, mechanical ventilation, and prolonged postoperative pain. They also had a significantly longer length of hospital stay, and cost per patient was significantly higher.

"Cardiac surgery in patients with OUD is safe but associated with elevated complication rates and greater resource utilization compared with cardiac surgery patients overall," Edward Soltesz, MD, MPH, surgical director at the Kaufman Center for Heart Failure Treatment and Recovery, Cleveland Clinic, Ohio, told Medscape Medical News.

"Our findings suggest that patients need not be denied cardiac surgery in urgent situations as a result of opioid use, but close postoperative monitoring is indicated," Soltesz said.

The study was published online December 5 in JAMA Surgery.

Limited Research

"Opioid use disorder has been a growing problem across the country for several years now," Soltesz said.

"At Cleveland Clinic, we see many of these patients who are here for cardiac issues or procedures and we wanted to better understand the patients with OUD as well as how their outcomes are affected when they undergo cardiac surgery," he reported.

Previous studies have focused on negative outcomes from prescription opioid overdose that can occur postoperatively, but studies specifically focusing on surgical outcomes are "limited," the researchers write.

To investigate this question, they analyzed data from the Healthcare Cost and Utilization Project National Inpatient Sample (NIS) database (January 1998 to December 2013), which is managed by the Agency for Healthcare Research and Quality.

The NIS database includes unweighted data from more than 7 million hospitalizations per year and weighted data from more than 35 million hospitalizations, representing a 20% stratified random sample of all discharges in a given year.

The researchers focused on patients who underwent isolated coronary artery bypass graft (CABG), valve surgery, aortic surgery, or a combination of these.

Patient-level variables included age, sex, race/ethnicity, insurance status, income level, admission status, and discharge disposition.

Primary outcomes included mortality, complications, length of stay, hospital charges excluding professional fees, cost, and discharge outcomes.

Complications included stroke, blood transfusion, wound infection, renal complication, cardiac complication, gastrointestinal tract complication, pulmonary embolism, deep vein thrombosis, pneumonia, mechanical ventilation, prolonged postoperative pain, and sepsis.

Younger Patients

Of 5,718,552 patients undergoing CABG, valve surgery, or aortic surgery between 1998 and 2013, 0.2% met the criteria for OUD.

Patients with OUD were younger than those without OUD (mean age, 48 years vs 66 years, respectively; P < .001).

The prevalence of OUD was considerably lower in older age groups: of participants at least 65 years old, 9.5% had OUD and 57.0% did not have OUD (P < .001).

Compared to patients without OUD, those with OUD were more likely to undergo valve surgery (47.5% vs 15.1%; P < .001) or aortic surgery (2.2% vs 1.3%; P < .001), and were more likely to have an urgent admission status (64.0% vs 33.6%; P < .001). However, they were less likely to undergo CABG (42.7% vs 71.7%; P < .001) or a combination of these procedures (7.6% vs 11.9%; P < .001).

In patients with OUD compared with those without OUD, admission status was significantly more likely to be emergent (64.0% vs 33.5%; P < .001).

During the 15-year study period, the number of cardiac surgery patients with a history of OUD significantly increased by nine-fold, from 0.06% to 0.54% of all annual cases (P < .001).

Although mortality rates did not significantly change during those years, overall morbidity increased from 56% to 74%.

Impaired Wound Healing

In an unadjusted analysis, in-hospital mortality was found to be statistically comparable between patients with and without OUD (3.1% vs 3.5%, respectively).

However, all complications were significantly higher in patients with OUD — with the exception of wound infection and gastrointestinal tract complications.

For patients with OUD, the median length of stay was significantly higher, as was the median total cost.

Moreover, patients with OUD were more likely to be discharged to long-term skilled inpatient facilities rather than home (odds ratio, 1.56; 95% CI, 1.47 - 1.72; P < .001).

There was an increased risk of mortality in black and Hispanic patients with OUD and those located in a Western region.

Being hospitalized at a facility which performed more than 200 surgeries per year had a protective effect on mortality. Moreover, there were no mortalities for case volumes greater than 2000 cardiac surgeries per year.

"A number of different mechanisms have been postulated to explain the increased risks of postoperative complications in patients with OUD," Soltesz said.

"Aside from the risk of withdrawal, with all its attendant physiologic consequences, patients with OUD have impaired wound healing and increased requirement for analgesics, both of which can contribute to any number of postoperative complications," he explained.

Patient Group "Challenging"

Commenting on the study for Medscape Medical News, Alexander Brescia, MD, cardiothoracic surgeon at the University of Michigan, Ann Arbor, said that previous research in all types of surgery, including cardiac surgery, has focused on long-term effects of persistent opioid use that began after the procedure.

In other words, it focused on surgery as the cause for the initial exposure to prescriptions opioids.

"In contrast, this study importantly characterizes patients who have already been using opioids prior to surgery," said Brescia, who was not involved with the research.

These patients "present a challenge for pain management after surgery, and identifying the specific risks in this population is important for all physicians treating these patients," he added.

The findings "suggest that it may be valuable to incorporate opioid use leading up to surgery, meaning opioid use as defined by the authors, into assessing a patient's risk prior to surgery," he said.

Brescia described preoperative risk assessment as "a highly important and detailed process prior to cardiac surgery," adding that the study "highlights an area in risk assessment that is not routinely quantified in practice, but perhaps should be."

The investigators conclude that "trends in patient volume and morbidity reported in our study suggest that cardiac surgeons are likely to encounter this population of patients more often now than in the past and should be prepared to adequately manage the perioperative factors specific to them."

The study authors and Brescia have disclosed no relevant financial relationships.

JAMA Surg. Published online December 5, 2018. Abstract

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