The opioid prescribing practices of surgeons: A comprehensive review of the 2015 claims to Medicare Part D

Background The Centers for Disease Control and Prevention have declared that the United States is amidst a continuing opioid epidemic, with drug overdose–related death tripling between 1999 and 2014. Among the 47,055 overdose-related deaths that occurred in 2014, 28,647 (60.9%) of them involved an opioid. Methods To determine if there are specific trends in opioid prescribing practices of specific groups of surgeons to better describe any regional or subspecialty trends that exist, the Part D Prescriber Public Use File was used to evaluate all prescription drug orders for Medicare beneficiaries with a Part D prescription drug plan for the 2015 calendar year. Only those providers with the specialty description corresponding to a surgical specialty were included in this study, using the provider's Part B claims. Results A total of 65,277,932 claims made to Part D by 90,253 surgeons in the 2015 service year were analyzed in this study, demonstrating statistically significant differences in the opioid prescribing practices of surgeons from different states, cities, practice settings, and subspecialties (P < .05). During this year, these surgeons' opioid medication claims cost the health care system $133,091,997.81 in drug benefits. Conclusion All health professionals with opiate prescribing privileges are entrusted with and responsible for the use of these medications; therefore, physicians have a crucial role in ensuring safe and effective use of this treatment option and the deterrence of its abuse. This is true in particular for surgeons given the acuity level and context of their practice.


INTRODUCTION
The Centers for Disease Control and Prevention (CDC) have declared that the United States is amidst a continuing opioid epidemic, with drug overdose-related death tripling between 1999 and 2014 [1,2]. During this same period, sales of prescription opioids in the United States have nearly quadrupled, with patients older than 40 years more likely to be prescribed opioids as well as more likely to use opioids than younger adults (ages of 20 and 39 years) [5]. Prescribing rates among surgeons (37% of all opioids prescribed) are second only to the prescription rates of pain medicine providers [6]. Surgeons' high rate of opioid prescription is likely motivated by the acuity of their pain treatment and the strong evidence that demonstrates the efficacy of opioid combinations in the treatment of postoperative pain [7][8][9].To this end, we have aggregated and analyzed provider-level Part D data from the Centers for Medicare and Medicaid Services (CMS) and the CDC with the goal of understanding the individual opioid prescribing practices of different surgical subspecialties; different practice environments; and cities, states, and regions to better describe potential foci that may help inform surgeons, policy makers, and the health care stake holders at large.

METHODS
There were 44.1 million people enrolled in Medicare Part D in the 2015 calendar year. This includes those on Medicare who 65 years and older and those on Medicaid who are younger than 65 years with permanent disabilities and have access to the Part D drug benefits. The Part D Prescriber Public Use File (PUF) is based on all beneficiaries enrolled in the Medicare Part D prescription drug program, which includes approximately 70% of all Medicare beneficiaries, an estimated 41.8 million persons. The PUF was used to query data on prescription drug events (PDEs) incurred by all Medicare beneficiaries with a Part D prescription drug plan for the 2015 calendar year. These data included Surgery Open Science 2 (2020) 96-100 Definition of an Opioid Drug. The list of drugs included in data analysis for an Opioid Drug referred to the Prescriber Drug Category List for opioids, which is based upon drugs in the Medicare Part D Overutilization Monitoring System. This list is originally published by the CDC (https://www.cms.gov/Medicare/Prescription-Drug-Coverage/ PrescriptionDrugCovContra/RxUtilization.html).
Definition of Urbanized Cities. The Census Bureau's urban-rural classification was used to define urban and rural areas. To qualify as an urban area, the territory identified according to criteria must encompass at least 2,500 people, at least 1,500 of which reside outside institutional group quarters. The Census Bureau identifies 2 types of urban areas: Urbanized Areas (UAs) of 50,000 or more people and Urban Clusters (UCs) of at least 2,500 and less than 50,000 people. Both UAs and UCs were counted as urban cities. Rural cities encompassed all population, housing, and territory not included within an urban area.
Death Rates Adjusted for Age. Deaths were classified using the International Classification of Diseases, Tenth Revision. Deaths by drug poisoning were identified using associated cause-of-death codes X40-X44, X60-X64, X85, and Y10-Y14. Death rates adjusted for age were calculated as the number of deaths per 100,000 persons using the direct method and the 2000 standard population. Death by drug overdose data were obtained from the National Center for Injury Prevention and Control, Division of Unintentional Injury Prevention's public database, a branch of the CDC. All calculated data were in accordance with the CDC's calendar year data for 2015.
Data Analysis. All analyses were performed to reflect the entire cohort. All statistical analyses, paired t test, and univariate analysis of variance were performed using R Statistical Software (Version 3.1.1, 2013; Vienna, Austria). were analyzed in this study. Provider subspecialty opioid prescribing practices varied significantly (P b .0001), with hand surgeons having a statistically significant higher rate of opioid prescription as compared to all their peers (61.0% of all prescriptions written to Part D beneficiaries, P b 0.0001, Fig. 1). Orthopedic surgeons had an opioid prescription rate of 48.6%, significantly greater than all specialties excluding hand surgeons (P b .0001). Although significantly less than hand surgeons and orthopedic surgeons, neurosurgeons had an opioid prescription rate of 40.6%, which was significantly greater than all other specialties other than surgical oncology (P b .0001). The mean rates of opioid prescription by state are summarized in Fig. 1 by surgical subspecialty. The overall mean rate of opioid prescription for all surgeons in this study was found to be 27.1% (Fig. 1  practices have been summarized in Supplemental Table 1 to provide a more detailed understanding of opioid prescribing practices in individual cities.

RESULTS
Furthermore, an analysis of rural versus urban practice environment correlation with rates of opioid prescriptions was calculated; on average, surgeons practicing in urban cities were found to have significantly greater rates of opioid prescription as compared to those practicing in rural areas (Fig. 2). To this end, the rates of opioid prescription by state were compared with the rates of age-adjusted mortality associated with drug overdose, and this relationship demonstrated a statistically significant correlation (P b .0001, equation: Opioid Claim Count = 102.882*number + 10,374.7).

DISCUSSION
The 65,277,932 claims made to Part D by 90,253 surgeons in the 2015 service year were analyzed in this study, demonstrating statistically significant differences in the opioid prescription prescribing practices of surgeons from different states, cities, practice settings, and subspecialties (P b .05). In 2015, these surgeons' opioid medication claims cost the health care system $133,091,997.81 in drug benefits. Based upon our analysis of the CDC's drug-related mortality data, these prescriptions may have cost the system much more.
The importance of high opioid prescription rates by surgeons cannot be emphasized enough because, although opiates can be the most effective pain management option in the short term, opiates present serious risks with initiation and continued use. These risks are the welldocumented and national epidemic of dependence and overdose-related mortality [10]. In the year of 2013 alone, an estimated 1.9 million people were dependent on or abused prescription opiates. Between 1999 and 2014, more than 165,000 people died from overdose deaths related to opioid pain medications [1,11,12]. Of all causes of accidental deaths, drug overdose has become the leading cause with 52,404 lethal drug overdoses in 2015 alone. Of these lethal drug overdose deaths, opioid overdose is the single greatest contributor, accounting for 20,101 deaths, or 38% in total [2]. In 2010, a Substance Abuse and Mental Health Services Administration survey reported that at least 16 million Americans had taken a prescription pain medication or non-medically indicated opioid at least 1 time in the past year, with 55% of these people also indicating that they procured the medication from a friend or relative free of cost. Furthermore, 17.3% of these people reported that they were given prescriptions for these pain reliever medications from a doctor [13]. In 2010, the New England Journal of Medicine reported a study that of the 2.4 million opioid-dependent people in the United States, 60% of their opioids were obtained either directly or indirectly from a physician prescription [14].
With regards to the distinct disparities in prescriptive tendencies between surgeon types, addressing the statistically significant rates of hand, orthopedic, and neurosurgeons could be helpful to conjecture that there is a need for improved pain management options for musculoskeletal diagnoses. Given the widespread knowledge that musculoskeletal diagnoses are commonly associated with opioid prescriptions and repeat opioid prescriptions, there is significant room for improvement of musculoskeletal pain management. Furthermore, Khalid et al found that there were no statistically significant regional differences between neurosurgeons prescribing opiates, which is interesting given the stark differences between the subspecialties most likely to prescribe opiates [16].
Of note and surprise, among the Part D beneficiary population, there are high rates of opioid prescription in urban cities at 26.4% compared to rural cities with 20.5% (P b .001) (Fig. 2). Anecdotally, there has been more focus on rural opioid addiction and overdose, which could indicate either a change as the opioid epidemic matures or a difference in opiate use in the general population compared to the CMS population.
The opioid epidemic is a complex issue affecting our country, with serious implications for public health and safety [1,15]. There are already federal, state, and institutional initiatives directed at developing appropriate responses to this crisis. For surgeons, the vast majority of our patients present with pain or pain-associated syndromes, and accordingly, most of our interventions require some course of opioid medications. As such, being aware of our prescribing practices is the first step to develop strategies to address this epidemic. The sparse number of surgical studies demonstrating optimization of opioid prescription practices is also an area of study that could use greater attention and resources with highlevel clinical studies to direct outcomes-based practice. Different surgical specialties should be aware of their rates of prescription as they compare to their peers. Likewise, different practice environments, cities, and states, although are treating many of the same conditions and providing a high standard of care, have a different approach to opioid prescription. It is our hope that the knowledge of the rates on a national context will help introspective adjustment and influence regulation and policy to help mitigate the rise in opioid-related deaths.
Study Limitations. The Part D Prescriber PUF detail file does not include claim, medication cost, or day supply associated with fewer than 11 Part D drug claims per provider; thus, the data presented here unfortunately underestimate the true Part D totals. Furthermore, most Medicare Part D beneficiaries are older (N65 years old), so these patients may represent more significant or at least advanced chronic pathology, with longer recovery times requiring more pain control than the general populace.
In conclusion, those with opioid prescribing privileges are given great responsibility, with the responsibility and authority to use these medications in safe, efficacious, and prudent manner in the treatment of their patients; therefore, physicians have an important role to play in responding to the opioid crisis. Surgeons have the opportunity to help to ensure safe and effective use and deter its abuse, especially in the acute context of their practice and among the elderly CMS population that is susceptible to opioid overdose. Further research in the opioid prescribing habits of surgical subspecialties in the general population outside of Part D plans would be highly beneficial for future studies to pursue.

Author Contribution
• Syed Ibad Khalid, MD: conceived and designed the analysis, collected the data, contributed data or analysis tools, performed the analysis, wrote the paper, approved the final version of the paper • Ryan Kelly, BS: collected the data, contributed data or analysis tools, performed the analysis • Rita Wu, BS and Amelia Y. Ni, BA BS: collected the data, wrote the paper • Ridha Khalid, MD: conceived and designed the analysis, wrote the paper, approved the final version of the paper • Owoicho Adogwa, MD, MPH: conceived and designed the analysis, wrote the paper, approved the final version of the paper • Joseph S. Cheng, MD, MS: conceived and designed the analysis, approved the final version of the paper

Conflict of Interest
• No authors have any conflicts of interest to report.

Funding Sources
• No external funding was used to support this study.