Friday, November 23, 2012

“Misbehavior” Does Not Denote Rx-Drug Abuse

Addicted BrainIdentifying prescription drug use disorders, whether abuse or addiction, in primary care patients taking controlled substances for pain is an ongoing challenge. So called “aberrant drug-related behaviors” (ADRBs) often have been suggested as denoting a drug use disorder of some type; however, according to new research this can be false and misleading.

Working at the Boston University Medical Center, researchers conducted a cross-sectional study to determine whether ADRBs documented in electronic medical records of primary care patients prescribed opioids and/or benzodiazepines for pain could serve as a proxy for identifying Rx-drug use disorders. Ellen C. Meltzer, MD and colleagues recruited 264 English-speaking patients (ages 18–60) with chronic pain (≥3 months), receiving ≥1 opioid analgesic or benzodiazepine prescriptions during the past year [Meltzer et al. 2012].

To determine past year Rx-drug use disorder, versus no such disorder, the researchers interviewed each patient using the Composite International Diagnostic Interview (CIDI), which is based on criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). Along with that, electronic medical records for each patient were reviewed for 15 prespecified ADRBs (eg, early refill, stolen medications, etc.; see list below) in the year before and year after study entry.

Writing in the November 2012 edition of Pain Medicine the researchers report that 61 participants (23%) met DSM-IV Rx-drug use disorder criteria and 203 (77%) had no such disorder. Almost all subjects — 85% of those with and without a drug-use disorder — had one or more ADRB documented. Furthermore, there were few differences noted in the frequencies of individual misbehaviors between the 2 groups

The only statistically significant difference between groups was on “appearing intoxicated or high,” which was documented more frequently among participants with Rx-drug use disorder (N=10, 16%) compared with no disorder (N=8, 4%), P=0.002. The most frequently reported ADRB — “emergency visit for pain” — did not discriminate between those with and without drug-use disorder (N=50, 82% Rx-drug use disorder group vs N=159, 78% no disorder group, P=0.6).

The researchers conclude that, among patients with chronic pain receiving prescription opioids and/or benzodiazepines, having at least one ADRB documented in their medical record is almost universal. And, the frequencies of the various “misbehaviors” considered to be ADRBs are similar among those with and without a Rx-drug use disorder. Therefore, reliance on nonsystematic documentation of ADRBs to identify Rx-drug use disorder in primary care patients with chronic pain may not be useful.

Based on these findings, Meltzer et al. suggest that healthcare providers (and researchers in the field) should be cautious about using ADRBs as a proxy for a Rx-drug use disorder. Prospective studies that more systematically assess ADRBs are needed before the true significance of these alleged misbehaviors and their validity as evidence of some disorder can be determined.

COMMENTARY: An important message of this research appears to be that many behaviors in patients with chronic pain commonly thought to be indicative of a prescription drug use disorder may be misleading. However, there were some limitations of this study to consider, in addition to its relatively small size.

First, the study relied on practitioners’ clinical observations and their extemporaneous, or ad hoc, entries into electronic medical records, without following a structured patient interview or behavioral assessment checklist of some type. In many cases there might be various interpretations of what “aberrant behavior” means in a clinical sense. For example, does “appearing intoxicated or high” rule out pain-related cognitive dysfunction or a drug interaction of some sort?

Meltzer and colleagues note, “Experts in pain medicine define ADRBs as behaviors suggesting out of control use of medications, one hallmark of addiction.” The ADRBs used in their study included: 1) appears intoxicated/high, 2) use of someone else's medication, 3) bought medication off the street, 4) extensive time discussing medication, 5) Involvement in an accident, 6) multiple prescription locations, 7) insists non-opioids do not work, 8) tried to get scripts from other prescribers, 9) urgent visit for pain, 10) need for early refill, 11) urgent visit for opioid pain medications, 12) insists on medication by name, 13) lost medication, 14) increase in dose without authorization, 15) reports stolen medication.

At face value it can be surmised that most of the ADRBs, without further qualification, would not clearly discriminate between those with or without a drug use disorder. Indeed, for example, many more patients without a disorder (N=29, 14%) were involved in an accident than those categorized as having a disorder (N=3, 5%). Also, roughly identical numbers of patients in both groups sought early refills of prescriptions and required urgent visits for pain, and similar equivocal patterns across groups were noted for the other ADRBs.

Secondly, using DSM-IV criteria to identify substance use disorders, particularly addiction, in persons with pain can be problematic [as discussed at length in an earlier UPDATE article here]. Many behaviors that might ordinarily denote substance abuse or addiction in a person without pain can be otherwise explained by the fears, anxieties, and motivations of persons coping with chronic pain. For example, as noted in the earlier UPDATE regarding addiction:

“When patients are maintained on opioids for the treatment of pain, there is currently no satisfactory means of distinguishing true addiction from problematic behaviors caused by a variety of factors other than addiction. Unfortunately, advances in understanding the neurobiological foundation of addiction have not been matched by any improvement in physicians’ ability to recognize and diagnose the condition.”

Meltzer et al. acknowledge the possibility of a “misclassification bias” in their study, which they say might have underestimated the prevalence of Rx-drug use disorder. More likely, however, the DSM-IV criteria they used, without adjustments for behaviors in persons with pain, probably overestimated the prevalence.

Many clinicians believe that they can almost intuitively identify patients with a substance abuse or addiction disorder; frequently, they rely on their own mental checklist of aberrant behaviors to indicate such. However, in the case of persons with pain those spontaneous judgments may be wrong more often than not. This points to the need for further education of clinicians on this topic if they are to equitably and effectively prescribe pharmacotherapy in patients with chronic noncancer pain. And, researchers in the field need to be more circumspect in their use of DSM criteria for assessing substance-use problems in persons with pain.

REFERENCE: Meltzer EC, Rybin D, Meshesha LZ, et al. Aberrant Drug-Related Behaviors: Unsystematic Documentation Does Not Identify Prescription Drug Use Disorder. Pain Med. 2012;13:1436–1443 [abstract here].

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