Potential Misuse and Inappropriate Prescription Practices Involving Opioid Analgesics
Published Online: August 12, 2013
Ying Liu, PhD; Joseph E. Logan, PhD; Leonard J. Paulozzi, MD, MPH; Kun Zhang, MS; and Christopher M. Jones, PharmD
The problem of abuse and overdose of prescription drugs has emerged as a major public health issue in the United States.1 In 2010, drug overdoses killed 38,329 Americans, more than the number killed in motor vehicle traffic crashes.2 Misuse or abuse of prescription drugs also led to 1.2 million emergency department (ED) visits, compared with 1.0 million ED visits related to illicit drugs such as heroin and cocaine.3 Opioid analgesics alone or in combination with benzodiazepines or other drugs accounted for nearly half of the drug overdose deaths and more than three-fourths of prescription drug–related ED visits in 2009.2,3
The majority of prescription opioids used for nonmedical reasons are diverted from prescriptions originally written for therapeutic use.4 Yet many opioid abusers obtain them directly from a doctor and/or pharmacy, often by fabricating pain symptoms, forging prescriptions, and engaging in doctor and pharmacy shopping (ie, obtaining multiple prescriptions from multiple providers or pharmacies).4,5 Providers and payers may be in a position to help enhance the safety of prescribed opioids and protect susceptible patients from becoming addicted to or overdosing on opioids. Among patients who were prescribed opioids, those receiving multiple opioid prescriptions, overlapping opioids, overlapping opioids and benzodiazepines, and opioids at high dosage levels are at greater risk for abuse and overdose.6-8
Despite the well-documented associations between usage patterns and risk, relatively little is known about the current prescription practices for opioid analgesics and the extent to which they might be contributing to the rising prescription drug abuse problem. A small number of studies using administrative data from a limited number of health plans have described general opioid use (eg, number of opioid prescriptions received, average daily dose, total days of supply) and/or potential misuse (eg, high daily dosage, overlapping opioids, overlapping opioids and benzodiazepines).9-13 However, these studies have generally limited their analyses to long-term (>90 days) opioid users9,10 and/or populations with specific types of noncancer pain (eg, back pain, headache).11,13
This study examines indicators of potential misuse by patients or inappropriate prescription practices by providers using one of the largest fully integrated commercial claims databases in the United States. The population of interest includes all adults with at least 1 opioid prescription regardless of their length of opioid use or indication for use with the exception of pain associated with cancer. Additional analysis reports differences in these indicators between men and women. Our results could be used to inform the monitoring of opioid use and to promote efforts to improve appropriate prescription practices by providers.
We conducted secondary data analyses of the 2009 Truven Health MarketScan Commercial Claims and Encounters databases, which consisted of data from approximately 100 payers and health plans for about 50 million individuals from all 50 states.14 MarketScan contains standardized, fully integrated, enrollee-level, de-identified claims across inpatient, outpatient, and prescription drug services. Our analysis drew data primarily from the pharmaceutical claims, which included outpatient drug name, class, dosage, and quantity for about 17.8 million (10.3 million females and 7.5 million males) enrollees aged 18 to 64 years. In addition, the outpatient service claims and inpatient admission records were used to identify the underlying pain diagnoses related to opioid use. Inpatient admission records were necessary because some opioid prescriptions were prescribed to enrollees at discharge.
Overall Study Population. We identified 13,097,589 opioid prescriptions for enrollees who were aged 18 to 64 years, were continuously enrolled in 2009, and did not have a cancer diagnosis in their outpatient or inpatient service claims (Figure). Cancer diagnoses were based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes including 338.3, 140-172.9, 174-215.9, 217-229.10, and 235-239.9. A list of analyzed opioids is provided in Table 1. Buprenorphine was excluded due to its primary use for treatment of opioid dependence. We excluded 1,216,388 (9.3%) opioid prescriptions that lacked the enrollee identification (ID) or dispensing information necessary for the calculation of predetermined outcome indicators. An additional 770,446 (5.9%) refill prescriptions were excluded due to inability to identify their original diagnoses. This selection process resulted in 11,110,755 (84.8%) opioid prescriptions filled by 3,391,599 enrollees as our overall study population.
Subpopulation With Identified Diagnoses. To calculate a subset of outcome indicators that are specific to certain types of pain, we linked opioid prescription claims to the diagnoses on outpatient or inpatient service claims by matching enrollee ID and the date of service. Consistent with the existing literature,15 we linked opioid prescriptions to the outpatient services or inpatient discharges that occurred within 14 days of the prescription dispensing dates. If multiple outpatient or inpatient records existed within this interval, we linked to the ones that occurred on the day closest to the drug dispensing dates. When inpatient and outpatient dates of service overlapped, we used the outpatient claims for the linkage. Prescription refills were assigned the diagnoses on the original prescriptions. We successfully linked 7,714,067 (69.4%) of the 11,110,755 opioid prescriptions to diagnoses for 2,833,224 enrollees (85.3% of the overall study population). Of the remaining 30.6% of prescriptions, 28.0% could not be linked because the outpatient services or inpatient admissions had occurred more than 14 days prior to the prescription dispensing date or in 2008; 2.6% could not be linked because MarketScan did not have the enrollee’s outpatient service claims.
We adapted outcome indicators from clinical guidelines and those developed previously by expert panels.8,11,12,16-19 These indicators captured both general opioid use as well as potential misuse by patients or inappropriate prescription practices by providers.
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