Spine Study Identifies Predictors of Chronic Narcotic Use

Using a prediction model, researchers were able to identify, with nearly 80 percent accuracy, which patients undergoing thoracolumbar spine surgery would still be taking narcotics two years postoperatively.

The prospective, observational study, presented during the North American Spine Society Annual Meeting by Erin Bigney, MA, of Canada East Spine Centre, used the Canadian Spine Outcomes and Research Network data alongside validated psychological measures.

The participants were 191 consecutively enrolled adult patients undergoing thoracolumbar spine surgery. Those who had previous spine surgery were excluded. Baseline measures included the Pain Catastrophizing Scale (PCS), Tampa Scale for Kinesiophobia, Multidimensional Scale for Perceived Social Support, Chronic Pain Acceptance Questionnaire (CPAQ), Oswestry Disability Index (ODI), numeric rating scales (NRSs) for back and leg pain, Short Form-12’s Mental Component Summary (MCS), narcotic use, and demographic variables.

The postoperative measure of interest was narcotic use at two-year follow-up. Narcotic use was collapsed into binary categories of “use” and “no use.” Chi square analysis and analyses of variance were used for categorical variables and continuous variables, respectively. Significant variables were built into a hierarchical regression to determine predictors of post­operative narcotic use. Significance was set at < 0.05.

From those data, the researchers created a regression model. The model included ODI, NRS for leg pain, time with condition, chief complaint, preoperative drug use, sex, MCS, PCS, and CPAQ data. Two years after surgery, 27.23 percent of the patients were using narcotics. The model correctly predicted use in 79.7 percent of cases and accounted for 39.6 percent of the variance in narcotic use. Above the other predictors, psychological variables accounted for 9.6 percent of the variance.

Erin Bigney, MA, reported results showing that surgeons can preoperatively predict which patients are at risk for chronic, postoperative narcotic use.

Predictions possible

The results show that surgeons can preoperatively predict which patients are at risk for chronic, postoperative narcotic use, Ms. Bigney explained. Patients with moderate to severe disability, high levels of leg pain, high scores on PCS helplessness (“There’s nothing I can do to help reduce my pain”), and low pain willingness (low preparedness of a person to experience increased pain in order to get something important done) at baseline were more likely to use narcotics two years after surgery. Postoperative narcotic use also was predicted by sex (with males at higher risk), chronicity (having symptoms for more than two years), and preoperative use of narcotics. “The majority of the conditions that predicted chronic narcotic use are not changeable or difficult to change, including [sex], pain levels, and disability. However, perception of your personal control over pain and your willingness to endure pain for increased function can be treated or altered,” Ms. Bigney said.

“As physicians, it would be valuable to be able to identify patients at risk for narcotic overuse, misuse, and dependency,” she said. “Previous research has concentrated on the effect of demographics, surgical factors, and previous narcotic use as primary predictors; however, psychological variables may be a contributing factor as well.”

Medical professionals are starting to recognize the impact of psychological variables on medical outcomes, Ms. Bigney said. “Psychological factors are instrumental in the spine patient’s postoperative quality of life, and a compromised mental health profile may set the spine patient up for failure.”

With the predictor model used in the study, “psychological factors did give significant information over and above that accounted for by the other predictor variables,” Ms. Bigney said. In fact, psychological variables were more predictive than sex or chief complaint and equally predictive as time with condition and previous narcotic use.

“This is a significant finding, as it is currently not standard practice for surgeons to investigate these variables prior to surgery.”

The holistic benefit

Managing chronic narcotic use is “imperative,” Ms. Bigney said, and it is central to the patient’s overall health and quality of life.

“Perhaps the most important part of the finding that psychological factors are predictive of postoperative narcotic use is that these factors are malleable,” she observed. “Both physical therapy and cognitive behavioral therapy, either individually or in combination, have been shown to improve patient pain catastrophizing and present surgeons with an opportunity to provide the patient with preventive resources.”

Identifying patients at risk contributes to improved outcomes. “Knowing which people will be most vulnerable to chronic narcotic use after surgery enables physicians to be selective in their prescribing procedures,” Ms. Bigney said. “By treating the patient holistically—and including them in the conversation—alternatives to narcotics, including education, cognitive-based therapy, and other medications, such as acetaminophen and nonsteroidal anti-inflammatory drugs, can be considered.”

She added that future research in this area might include a clinical trial introducing the use of physical therapy and/or cognitive behavioral therapy to reduce patient pain catastrophizing and improve pain willingness prior to surgery to determine whether those approaches lead to reduced incidence of chronic opioid use.

Ms. Bigney’s coauthors of “Preoperative Psychological Factors Significantly Add to the Predictability of Chronic Narcotic Use: A Two-Year Prospective Study” are Neil A. Manson, MD, FRCSC, of Dalhousie University; Kate Ellis, BA, of Canada East Spine Centre; Eden A. Richardson, BA, of Canada East Spine Centre; Dean A. Tripp, PhD, of Queen’s University; and Edward P. Abraham, MD, of Saint John Regional Hospital.

Terry Stanton is the senior science writer for AAOS Now. He can be reached at tstanton@aaos.org.

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