Saturday, August 24, 2013

Remarkably Low Opioid Abuse in Pain Patients

A recently reported study evaluated the prevalence, characteristics, associated healthcare resource utilization and costs of diagnosed abusers of prescription opioids in a large managed care population. While such analgesic abuse may be a growing problem, the prevalence rates of abuse and addiction among patients with pain appear to be surprisingly low and not supportive of the so-called “epidemic” claimed by many sources.

For this new study, Carl L. Roland, PharmD and colleagues identified all patients aged ≥12 years with prescription opioid abuse in the Thomson MarketScan Commercial and Medicare Supplemental research databases spanning January 1, 2005 to September 30, 2010 [Roland et al. 2013]. Diagnoses of “opioid abuse” were based on ICD-9-CM (International Classification of Disease, 9th Revision, Clinical Modification) codes denoting opioid abuse, opioid addiction, and/or poisoning (eg, overdose) with opioid agents (excluding heroin). The databases included information on 70.5 million persons in the United States. For comparative analyses, opioid abusers were matched 1:3 on demographic variables with non-abusers.

Writing in the May/June 2013 edition of the Journal of Opioid Management, Roland et al. report that the overall prevalence of diagnosed “opioid abuse” during 2005-2010 was 0.195%, and there had been more than a twofold increase from 2005 to 2010 (0.067% to 0.145%). Prevalence was calculated as the number of unique individuals with an ICD-9-CM coding divided by the total number of unique enrolled patients for the period of interest, reported as a percentage.

During 2005-2010, diagnosed opioid abuse was more prevalent in males (0.220%), those aged 18-25 years (0.271%), and those from the Northeast region of the U.S. (0.231%). Furthermore, abuse was more common in patients with a comorbidity of pain (0.462%) and in those prescribed opioids for pain (0.924%).

In comparative analyses, a total of 15,398 opioid abusers were matched to 46,194 non-abuser controls. As might be expected, medical comorbidities were significantly (p < 0.0001) higher in opioid abusers versus non-abusers. Also, healthcare resource utilization was significantly greater for abusers than non-abusers, and total all-cause-costs were higher for abusers than non-abusers.

The authors conclude that prescription opioid abuse — ie, abuse, addiction, poisoning — has increased over time and such behaviors are associated with significantly greater health resource utilization and costs compared with non-abusers. They further state that results from this present study affirm those of other research using similar methodologies but different databases.

COMMENTARY:
First, it must be noted that this study was sponsored by and the entire research team was employed by Pfizer Inc., New York, NY. Some readers may question whether data collection and interpretation might have been biased by commercial conflicts of interest of some sort.

Secondly, there may be some doubts as to whether ICD-9-CM codes used for classifying opioid abuse and addiction were sufficiently sensitive and specific for purposes of this study. Along with that, proper attribution of coding depended on clinician recognition of opioid abuse or addiction, and the extent of their training and skills in doing this was unknown.

Despite these concerns, it is astounding that the prevalence of opioid abuse — representing abuse/addiction/poisoning combined — during 2005-2010 in this very large population of patients with pain was <0.2%. Specifically among those prescribed opioid analgesics, the rate was <1.0%. Even with a large margin of error, and potential biases, these data would seems to belie recent declarations of an opioid abuse/addiction “epidemic” — at least among patients being treated with opioids for pain conditions.

Controversies surrounding prescription-opioid abuse and addiction were discussed in a lengthy UPDATE [here]. Review studies have noted opioid abuse/addiction rates of 0% to 50% among patients in pain treatment, and opponents of opioid treatment for chronic pain often claim 30% of patients may become addicted to those analgesics. Certainly, this is still a poorly defined and frequently confusing topic and, most certainly, data in this latest study suggest that the prevalence of “abuse” denoted by ICD-9-CM codes, which also encompass addiction, is of small proportions.

REFERENCE: Roland CL, Joshi AV, Mardekian J, et al. Prevalence and cost of diagnosed opioid abuse in a privately insured population in the United States. J Opioid Management. 2013(May/June);9(3):161-175 [abstract here].

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