Strong Correlation Between Nonopoid Substance Abuse Disorders and Therapeutic Opioid Addiction

Patients with such disorders 28 times more likely to become addicted to opioids

Thomas A. Robinson, J.D., the Feature National Columnist for the LexisNexis Workers’ Compensation eNewsletter, is a leading commentator and expert on the law of workers’ compensation.

It has been known for some time now that people with prior substance abuse disorders are at risk for addiction to prescription opioids. According to a recent study published in The Journal of Pain, persons with nonopioid substance abuse disorders are 28 times more likely to develop therapeutic opioid addiction (“TOA”) when undergoing long-term opioid therapy than persons without such disorders. Moreover, the study suggests that the stronger the opioid dose during such treatment therapy, the more likely the patient will develop TOA. The researchers observe that their study, therefore, demonstrates the importance of obtaining a detailed and accurate substance use history prior to prescribing opioids and suggests further that opioid prescriptions should be avoided or at least severely limited in for patients who do not show clear improvement in pain or functional impairment. [See See Huffman, Kelly L., PhD, et al., “Nonopioid Substance Use Disorders and Opioid Dose Predict Therapeutic Opioid Addiction,” The Journal of Pain, 16:2, February 2015, pp. 126–34]

Epidemic of Prescription Opioid Abuse and Addiction

As noted by the researchers, the number of opioid prescriptions to patients with chronic noncancer pain has increased significantly since the late 1980s. Prescription opioids are now the leading cause of unintentional drug overdose deaths. Health care providers face an uneasy dilemma, note the researchers. They must weigh the potential benefits of long-term opioid therapy with the risk of misuse or addiction and yet, according to the researchers, there is “a dearth of reliable information on the prevalence of misuse in those who receive it.”

Study Methodology

The study sought, therefore, to examine the risk of TOA in a group of patients undergoing long-term opioid therapy at the time of admission to a pain rehabilitation program. Utilizing data related to 352 outpatients with chronic noncancer pain who were admitted to such a rehab program between January 2010 and March 2011, the researchers included cases in which the patients were either undergoing long-term opioid therapy at the time of admission or had been weaned from opioids as part of chemical dependency treatment (or by virtue of running out of opioids) directly before admission. Patients were excluded if:

"1) they had a history of nonmedicinal opioid use that preceded the introduction of therapeutic opioids; 2) they had abused therapeutic opioids but did not meet full criteria for TOA; or 3) the diagnosis of TOA could not be excluded or made conclusively…"

Factors such as gender, race/ethnicity, disability status, or comorbid conditions—e.g., chronic disease, psychiatric illness, and substance use disorders—were not used as exclusionary factors. After exclusions, data related to 199 participants remained in the study.

Addiction All Too Common Among Patients Receiving Long-Term Opioid Treatment

Of these remaining study participants, 87 were diagnosed with TOA (43.72%). In patients who had no known history of substance abuse, the percentage was lower—one in four were determined to have TOA. Patients with a known substance abuse history fared much worse; more than four out of five developed TOA. Age and sex appeared to be an important factor,  with young males being particularly susceptible to developing TOA. Marital status did not appear to be related to TOA development.

The researchers constructed a binary model that included both opioid dose and lifetime history of a substance abuse disorder as predictor variables. The results yielded a final model in which both life history of substance abuse disorder and morphine equivalence dosage at admission showed a highly statistically significant association with TOA, after adjustment for age and gender. Using this model, the researchers determined that those patients with a lifetime history of a substance use disorder were 28 times more likely to develop TOA than those without such a history. Moreover, increased dosage of opioids also increased the odds of TOA. For example, the researchers determined that where dosage was increased by 50-mg, the result was to increase the odds of TOA by 73 percent.  Dosage increases in the 100-mg range increased the TOA risk by 300 percent.

Addiction High Even Among Those With No Prior Abuse History

Although the researchers found the prevalence of total TOA in the study higher than that shown in other studies, they suggested that their number was probably conservative, since they had excluded patients with a clear history of nonmedical opioid use and those patients who had abused prescription opioids but who had not met full TOA criteria. There was some element of self-selection; many of the patients studied had been referred to the pain rehabilitation clinic “precisely because of difficulties with medication use.” The researchers added that study participants also underwent rigorous and comprehensive diagnostic evaluations.  Those evaluations likely resulted in the detection of a number of substance abuse disorders where the patients’ actual symptoms were subtle. According to the researchers, earlier studies that had relied upon physician reporting or retroactive medical record analysis tended to report only the most severe cases of TOA.

Study Limitations

The researchers acknowledge that the results of their study may not be generalizable to other patient populations.  For example, while patient populations with long-term intractable pain tend also to report high levels of distress and many have additional comorbidities, such as depression, anxiety, and posttraumatic stress disorder, patients with short-term pain issues may not be so susceptible to TOA. The researchers also acknowledged that patients with substance use disorders were likely overrepresented in the study sample since the pain rehabilitation program that treated the patients was well-known and had an excellent reputation for successful treatment. Studies using larger patient populations are needed. The results of those studies might be different, indicated the researchers.  They countered, however, that the very particularity of their study population could be viewed as a strength. They also noted that their study did not address the question of whether higher doses of opioids lead to addiction or rather that addiction leads to higher doses. They allowed that both situations could be true.

Time Spent on Screening Process Should Be Worthwhile

The researchers acknowledge that their study procedures were time-consuming and that their study processes would be difficult to follow within many pain management settings. Nevertheless, they indicate that time spent on the screening process should be worthwhile. Medical care providers ignore to their patients’ detriment the fact that the TOA risk is most pronounced in patients with substance use disorders (as indicated above, 83 percent of such patients developed TOA). Taking the time to make an early determination of risk is vital since patients with substance use disorders are probably not only more likely to have chronic pain but also more likely to seek opioids for treatment. Careful monitoring of prolonged opioid use is required, say the researchers. Patients who do not achieve substantive benefit from opioid prescriptions should be transitioned to other treatment.

Workers’ Compensation Perspective

This study underscores the need for the proposed screening tools in the treatment of workers’ compensation patients. There can be little question that the appropriate use of opioid drugs to treat chronic injuries in the Workers’ Compensation System continues to be a serious problem.

In 2014, the California Division of Workers’ Compensation posted proposed treatment guidelines for the use of opioid medications in the treatment of workers’ compensation patients. Those proposed guidelines specifically recommended the use of screening tools to identify a predicted increased risk for substance misuse/abuse. In those cases, the guidelines indicated that chronic opioid treatment should only be initiated if other alternatives are not viable.

The following are real life examples of workers’ compensation patients who had a prior substance abuse problem and what happened when they were prescribed opioids to treat pain for their injuries:

History of prior substance abuse not initially taken. A nurse with a history of substance abuse was injured after a patient threw him against a wall. The original diagnosis was that of a right shoulder strain. The treating physician originally prescribed the anti-inflammatory Celebrex. Over the course of approximately six years, the employee is now claiming injury to both shoulders, both arms and neck. His current prescriptions include Ambien, Activan, Lidoderm patches, Lyrica, Norco, Oxycontin, and Morphine for “break-through” pain. Interestingly, although no history of the employee’s prior substance abuse was initially taken, approximately six months after his initial injury, the treating physician did specifically express concern over what he described as “drug seeking behavior.” This occurred after the treating physician found out that the employee was also receiving opioid medications from a different physician.

Employee doesn’t inform physicians of extensive history of drug abuse. A production worker and his employer stipulated to a work-related injury when a pallet slipped and jammed his right arm.  At hearings, the employee  frequently appeared confused and had poor memory. He had a history of criminal convictions, including multiple burglaries and drug offenses and conspiracy to manufacture methamphetamine. He admitted to substance abuse problems: alcohol, methamphetamine, marijuana, and cocaine. He requested prescription narcotic medications from his physicians but didn’t inform them of his extensive history of drug abuse. One of his physicians confronted him about using a one-month supply of Percocet 5mg tablets at twice the recommended pace. Upon re-evaluation and continued medical management of chronic right upper extremity pain, he stated he took 7 or 8 Percocet 5mg tablets a day until they were gone, and then he used illegal drugs to help with the pain. Another physician reported that the employee should not have further access to opioid medications since he was at maximum medical improvement and he clearly lacked the insight as to the appropriate use of these drugs. The physician further noted that with co-existing use of illegal drugs, there was a high risk of inappropriate utilization and/or diversion of these narcotics. The employee then sought treatment for opioid withdrawal. The judge in the case stated that the employee was “drug-seeking before his injuries and is drug-seeking now.” The judge found that the employee had not met his burden of proving that the work injury caused aggravation of his mental condition or his drug abuse propensities.

Doctor outside chain of workers’ comp physicians prescribes fentanyl and employee overdoses and dies. The employee sustained an industrial injury to his left knee as the result of a motor vehicle accident. Later that same month, he died from an overdose of pain medication. The pain medication, fentanyl, had been prescribed to him in patch form by a personal physician outside the chain of physicians authorized to treat for his work-related knee condition. Fentanyl is an opioid with a potency 50 to 100 times that of morphine. Apparently the decedent used the patches contrary to instructions and succumbed to an overdose of fentanyl. The decedent had abused drugs and alcohol in the past. Earlier that year, he sought medical care for depression, anxiety, stress, and sleeplessness. He received prescriptions for a variety of medications, including Prozac, Trazodone, Clonazepam, Xanax, Restoril, Celexa, Valium, Zoloft, Ocazepam, and Seconal. One of the physicians treating the decedent suspected that he was bipolar and told him to schedule an appointment at a mental health facility. The deceased was subsequently seen at such a facility and referred to a psychiatrist. The psychiatrist remarked that the deceased expected to be placed on antidepressants and reported his concern that the deceased was facing "a kind of decompensation with nervous exhaustion." The next day, and before he had the work-related accident in question, the decedent requested Seconal and pain medications for knee pain. With respect to the claim for death benefits, one psychiatrist opined that the decedent suffered from a pre-existing mood disorder, which led to his excessive use of drugs, effectively self-medicating his condition, both before and after the accident, and resulted in his death. The judge credited this psychiatrist’s explanation of the decedent’s death and concluded there was no persuasive evidence to establish that the decedent's work-related knee injury aggravated or accelerated his mood disorder or otherwise caused the overdose. The judge therefore denied the claims for death benefits.

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