Preoperative Opioid Use Significantly Impacts Postoperative Opioid Course

Surgical patients are often given opioids postoperatively and may already be taking them preoperatively to manage chronic pain. When used appropriately, these medications can improve recovery, but prolonged use is associated with many risks, including addiction, overdose, physical injuries, and all-cause mortality.

Researchers at the Veterans Health Administration sought to determine whether peri-operative opioid use affects time to cessation of opioids postoperatively,¹ as has been previously suggested.² The researchers also sought to better define the epidemiology of perioperative opioid use.

“Despite widespread use of perioperative opioids, their clinical epidemiology and standards of care remain poorly defined,” wrote the authors. “Identifying the patterns of preoperative opioid use, and the timing and associated predictive factors for post-operative cessation has been understudied, particularly at the population-relevant levels of thousands of patients.”

The study investigators examined data from the electronic medical records for all patients who underwent surgery at 1 of 120 VA hospitals and had subsequent hospital stays of at least 1 day in the fiscal year 2011 (October 1, 2010 through September 30, 2011). Patients with metastatic cancer were excluded from the study, and the population was restricted to patients who received one or more opioid prescriptions within 90 days following their surgery. This yielded 64 391 patients who had undergone a diverse set of surgeries.

The researchers assessed patients’ preoperative opioid use for 180 days prior to hospital admission and classified it as: opioid-free; tramadol only; acute/intermittent use of short-acting (SA) opioids (≤90 days); chronic use of SA opioids (>90 days); or use of any long-acting (LA) opioid. Time to opioid cessation was calculated from the first day of post-operative opioid use to 365 days, with cessation defined as 90 consecutive days with no opioid prescriptions.

The investigators found the study population to be quite homogeneous, consisting primarily of white older men (≥55 years) residing in urban areas. The comorbidity burden was high (38% had a Charlson score >2), and many patients experienced chronic pain before (59%) and after (57%) their surgery. There was also a high prevalence of substance use (10%), nicotine use (16%), major depression (7%), and post-traumatic stress disorder (12%).

Preoperative opioid use varied widely, with 45.7% (n=29 419) opioid-free, 7.5% (n=4849) on tramadol only, 24.1% (n=15 444) on SA opioids acutely or intermittently, 17.5% (n=11 259) on SA opioids chronically, and 5.2% (n=3320) on LA opioids. Patients who were opioid-free preoperatively had the shortest time to opioid cessation postoperatively, taking a median of 15 days (interquartile range [IQR], 10 to 41 days). Patients with the longest median time to cessation were those taking SA opioids chronically (365 days; IQR, 259 to 365 days) and those taking LA opioids (365 days; IQR, 323 to 365 days), with more than half of the patients in these groups not ceasing opioids within the first 365 days following surgery.

Although use of SA opioids acutely or intermittently was associated with a substantially greater risk of prolonged opioid use than taking no opioids (hazard ratio [HR], 1.96; 95% confidence interval [CI], 1.92 to 2.00), the risk was lower than that observed for tramadol only (HR, 3.03; 95% CI, 2.94 to 3.13), chronic SA opioid use (HR, 9.09; 95% CI, 8.33 to 9.09), or LA opioid use (HR, 9.09; 95% CI, 8.33 to 10.00).

When other risk factors for prolonged postoperative use were examined, the risks were found to be substantially lower, with hazard ratios closer to 1. Such risk factors included chronic pain, substance abuse, presence of affective disorders, longer hospital stays, younger age, and increased comorbidities, among others. Only nicotine use was found to be a significant independent risk factor for extended time to cessation, and the authors note that future studies should more closely evaluate its effect on opioid cessation postoperatively.

Based on their findings, the study investigators conclude that preoperative opioid use is a better predictor for prolonged postoperative opioid use than pain, substance abuse, and affective disorder. They note that these findings may have 2 key clinical implications: 1) that examination of whether or not a patient is on an opioid regimen before surgery is not enough to determine risk, as opioid type and usage patterns can have a significant impact on risk levels; and 2) that both preoperative and postoperative interventions may require modification to ensure timely cessation of postoperative opioids.

References

1. Mudumbai SC, Oliva EM, Lewis ET, et al. Time-to-cessation of postoperative opioids: a population-level analysis of the Veterans Affairs Health Care System. Pain Med. 2016 Apr 15. pii: pnw015. [Epub ahead of print]
2. Carroll I, Barelka P, Wang CK, et al. A pilot cohort study of the determinants of longitudinal opioid use after surgery. Anesth Analg. 2012;115(3):694-702.