Abstract
Purpose:
Opioids are commonly prescribed for acute pain after surgery. However, it is unclear whether these prescriptions are usually modified to account for patient age and, in particular, opioid-related risks among older adults. We therefore sought to describe postoperative opioid prescriptions filled by opioid-naïve adults undergoing four common surgical procedures.
Methods:
This retrospective cohort study used individually-linked surgery and prescription opioid dispensing data from Ontario, Canada to create a population-based sample of 135,659 opioid-naïve adults who underwent one of four surgical procedures (laparoscopic cholecystectomy, laparoscopic appendectomy, knee meniscectomy or breast excision) between 2013 and 2017. Patient age, in years, was categorized as 18–64, 65–69, 70–74 and 75 and over. Postoperative opioid prescriptions were identified as those filled on or within 6 days of surgical discharge date. For those who filled a prescription, we assessed the total morphine milligram equivalent (MME) dose, types of opioids and any subsequent opioid prescriptions filled within 30 days of surgical discharge date. Results were presented stratified by surgical procedure.
Results:
For three of the four surgical procedures we assessed, the proportion of patients who filled a postoperative opioid prescription decreased with age (p<0.001 for trend) and there was a small shift in the type of opioid (more codeine or tramadol and less oxycodone; p<0.001 for trend). However, the total MME dose of the initial prescription(s) filled showed minimal age-related trends.
Conclusions:
The proportion of opioid-naïve patients filling postoperative opioid prescriptions decreases with age. However, postoperative opioid prescription dosage is not typically different in older adults.
Keywords: Surgery, Analgesics, Opioid, Adult
INTRODUCTION
In Canada and the United States, roughly one in five older adults (aged ≥ 65 years) is dispensed an opioid each year.1, 2 However, due to decreased drug metabolism, increased risk of polypharmacy and prevalence of cognitive impairment and co-morbid conditions, older adults are also considered to be at higher risk of opioid-related harm.3–5 When considering opioids for older adults, prescribers are advised to start low (dose) and go slow (titrate).4–6 Although empirical evidence to translate these recommendations into clinical practice is lacking, when prescribing opioids to older adults, starting at 25% to 50% of the recommended dose for a younger adult has been suggested.7–10 Yet clinicians must also balance the risks against concerns of undertreated pain in this population.7,10
Pain after surgery is one of the most common indications for initiating opioids,11,12 yet there is relatively little evidence to guide opioid prescribing in this setting. Guidelines on the management of postoperative pain recommend individualized care, but acknowledge gaps in evidence and offer no recommendations specific to older adults.13 The American College of Surgeons National Surgical Quality Improvement Program/American Geriatrics Society best practices guideline on perioperative management of older adults states: “….use of [opioid analgesic] medications beyond the minimum doses needed to achieve adequate analgesia should be avoided.”14
A review of studies reporting age-related patterns of postoperative pain and analgesic consumption found mixed results.15 To date, few studies have been able to assess age-related patterns of postoperative opioid use; they are often restricted to individuals either over or under age 65, and sometimes a subset of opioid medications, all reflecting eligibility for health care coverage.16–19 As such, our objective was to use a population-based cohort of adults (age 18 years and over) to describe opioid prescriptions filled after surgery and in relation to patient age. We hypothesized that, given concerns about higher risk of opioid-related harm in older adults,3–5 patterns would reflect prescribers’ tendency to tailor opioid prescriptions for older adults. More specifically, with increasing age, the proportion of patients who fill a prescription would decrease. Also, among those who fill a prescription, both the total morphine milligram equivalent (MME) of the initial prescription and likelihood of a subsequent opioid prescription (within 30-days) would also decrease with age. We also expected age-related trends in the type of opioid prescriptions filled, but had no prespecified hypotheses except that tramadol may be less common among older adults, in part because of potential drug interactions4,5 but also because itis not included in the Ontario Drug Benefits program (Ontario’s public drug program that covers most of the cost of many prescription drug products for older adults).20
METHODS
We conducted a population-based cohort study of adults (aged ≥ 18 years) undergoing four common surgical procedures (laparoscopic cholecystectomy, laparoscopic appendectomy, knee meniscectomy or breast excision), between July 2013 and March 2017, in Ontario, Canada. We chose these procedures as they are frequently performed, low-risk procedures.21 Discharge Abstract Database, Same Day Surgery and Narcotics Monitoring System (NMS) data were linked using unique encoded identifiers and analyzed at ICES (formerly known as the Institute for Clinical Evaluative Sciences). NMS contains all opioid dispensing data irrespective of how the prescription was paid for,22 and, for those residents who are eligible for universal health coverage (nearly the entire population of approximately 14 million), can be individually-linked to other health data.
We included the patient’s first eligible procedure during the study period. We excluded individuals who: (1) filled a methadone or buprenorphine prescription or filled another opioid prescription with total duration ≥ 7-days,23 in the previous year (i.e., to create an opioid-naïve cohort); (2) were not discharged home (e.g., were transferred to another hospital and thus their opioid prescriptions would not be captured in the Narcotics Monitoring System);22 (3) had a hospital length of stay ≥ 4-days (i.e., to exclude those who may have experienced significant surgical complications);16 or (4) died prior to 30 days after surgical discharge (i.e., to ensure complete follow-up).
The primary outcome was postoperative opioid prescription filled for oral tablet forms of any of: codeine, fentanyl, hydromorphone, meperidine, morphine, oxycodone, pentazocine, tapentadol or tramadol, filled within 7 days16,21 (i.e., on the hospital discharge date or within 6 days subsequent). The secondary outcomes, defined only for the subset who filled a postoperative opioid prescription, were the characteristics of the first prescription(s) filled during these 7 days: (1) total MME,24 treated as continuous and categorized as ≤ 150 or >150 to reflect dose and duration guidance for opioid prescribing for people with acute pain (i.e., ≤ 50 MME/day for 3 days or less)25 and (2) type of opioid (categorized as whether the prescription(s) included the most commonly dispensed opioids, i.e., indicators for each of codeine, oxycodone, hydromorphone or tramadol).12 Among those who filled a postoperative opioid prescription, we also assessed whether they filled a subsequent opioid prescription(s) within 30 days of the hospital discharge date. We also conducted a sensitivity analysis to assess our primary outcome using opioids filled within 30 days.23
We characterized patients by age, in years, as adults (18–64) or older adults (65–69, 70–74 and ≥ 75). We used proportions (with 95% confidence intervals and test for trend) to describe categorical outcomes and medians and interquartile ranges to describe total MME – all stratified by surgical procedure.
The use of data was authorized under section 45 of Ontario’s Personal Health Information Protection Act, which does not require Research Ethics Board review. Analyses were conducted using SAS (version 9.4; SAS Institute Inc, Cary, NC).
RESULTS
Patient characteristics
After exclusions (Supplementary Figure S1), the cohort consisted of 135,659 surgical patients. The age- and sex-profile of the patients, as well the type of surgery (inpatient vs. outpatient) varied by surgical procedure (Supplementary Table S1). Overall, roughly 20% were over the age of 65 but older adults accounted for a disproportionately smaller number of appendectomies and knee meniscectomies. Women accounted for nearly all breast excisions and the majority of laparoscopic cholecystectomies, but men underwent more knee meniscectomies. Most of the procedures were done as outpatient surgery, except appendectomies which were almost always inpatient.
Postoperative opioid prescription
Across all surgeries, roughly three quarters of patients filled a postoperative opioid prescription (Supplementary Table S1). Except for knee meniscectomies, the proportion who filled a prescription decreased with age (Figure 1). However, among those who filled a prescription, the median and interquartile ranges of the total MME of the initial prescription(s) were similar across age categories for all surgical procedures (Table 1 and Supplementary Figure S2). The proportion who filled a prescription with an initial dose >150 MMEs decreased with age for all procedures except knee meniscectomy (Table 1). Among those who filled a prescription, the type of opioid also varied by age (Table 1). Except for breast excision, the proportion who received codeine increased with age. Except for knee meniscectomy, the proportion who received oxycodone decreased with age. Tramadol was not less common among older adults. Contrary to our hypothesis, the proportion who filled a subsequent opioid prescription within 30 days decreased with age only for breast excision and increased with age for laparoscopic cholecystectomy (Table 1). The sensitivity analysis assessing our primary outcome using opioids filled within 30 days (Supplementary Figure S3) was consistent with the primary analysis (Figure 1).
Figure 1.
Proportion of patients filling a postoperative opioid analgesic prescription within 7-days, with 95% confidence intervals and p-value for trend test, by surgical procedure and age group (years), opioid-naïve adults, in Ontario, Canada, 2013–2017
Table 1.
Postoperative opioid prescription(s) characteristics and subsequent opioid prescription(s), by surgical procedure and age group, opioid-naïve adults, in Ontario, Canada, 2013–2017
| Age (years) | ||||||
|---|---|---|---|---|---|---|
| 18–64 | 65–69 | 70–74 | 75+ | ptrend | ||
| Laparoscopic cholecystectomy | (n = 43 238) | (n = 3694) | (n = 2563) | (n = 2930) | ||
| Total dose, MME | Median (IQR) | 135 (113–225) | 135 (113–225) | 135 (113–188) | 135 (108–188) | |
| >150, n (%) | 15 938 (36.9) | 1277 (34.6) | 835 (32.6) | 918 (31.3) | <0.001 | |
| Type of opioid, prescription(s) included: | Codeine, n (%) | 16 451 (38.1) | 1477 (40.0) | 1110 (43.3) | 1314 (44.8) | <0.001 |
| Oxycodone, n (%) | 13 295 (30.8) | 1077 (29.2) | 664 (25.9) | 768 (26.2) | <0.001 | |
| Tramadol, n (%) | 8858 (20.5) | 780 (21.1) | 522 (20.4) | 557 (19.0) | 0.161 | |
| Hydromorphone, n (%) | 4031 (9.3) | 317 (8.6) | 233 (9.1) | 254 (18.8) | 0.140 | |
| Subsequent opioid prescription filled within 30-days, n (%) | 2089 (4.8) | 128 (3.5) | 94 (3.7) | 117 (4.0) | <0.001 | |
| Laparoscopic appendectomy | (n = 19 333) | (n = 559) | (n = 326) | (n = 335) | ||
| Total dose, MME | Median (IQR) | 135 (113–225) | 135 (113–188) | 135 (100–188) | 135 (80–150) | |
| >150, n (%) | 6323 (32.7) | 180 (32.2) | 96 (29.5) | 83 (24.8) | 0.002 | |
| Type of opioid, prescription(s) included: | Codeine, n (%) | 6120 (31.7) | 187 (33.5) | 115 (35.3) | 121 (36.1) | 0.019 |
| Oxycodone, n (%) | 6540 (33.8) | 173 (31.0) | 89 (27.3) | 69 (20.6) | <0.001 | |
| Tramadol, n (%) | 3709 (19.2) | 105 (18.8) | 66 (20.3) | 86 (25.7) | 0.012 | |
| Hydromorphone, n (%) | 2501 (12.9) | 82 (14.7) | 52 (16.0) | 50 (14.9) | 0.043 | |
| Subsequent opioid prescription filled within 30-days, n (%) | 1106 (5.7) | 32 (5.7) | 11 (3.4) | 16 (4.8) | 0.134 | |
| Knee meniscectomy | (n = 6720) | (n = 472) | (n = 239) | (n = 141) | ||
| Total dose, MME | Median (IQR) | 225 (135–300) | 225 (135–300) | 225 (135–300) | 225 (150–360) | |
| >150, n (%) | 4593 (68.4) | 337 (71.4) | 160 (67.0) | 98 (69.5) | 0.655 | |
| Type of opioid, prescription(s) included: | Codeine, n (%) | 3539 (52.7) | 269 (57.0) | 153 (64.0) | 87 (61.7) | <0.001 |
| Oxycodone, n (%) | 2465 (36.7) | 178 (37.7) | 71 (29.7) | 53 (37.6) | 0.340 | |
| Tramadol, n (%) | 858 (12.8) | 49 (10.4) | 27 (11.3) | 18 (12.8) | 0.341 | |
| Hydromorphone, n (%) | 398 (5.9) | 22 (4.7) | * | * | * | |
| Subsequent opioid prescription filled within 30-days, n (%) | 314 (4.7) | 32 (6.8) | 13 (5.4) | 7 (5.0) | 0.234 | |
| Breast excision | (n = 16900) | (n = 3045) | (n = 2318) | (n = 2269) | ||
| Total dose, MME | Median (IQR) | 135 (113–188) | 135 (113–188) | 135(113–180) | 135 (90–180) | |
| >150, n (%) | 5803 (34.3) | 1068 (35.1) | 788 (34.0) | 625 (27.6) | <0.001 | |
| Type of opioid, prescription(s) included: | Codeine, n (%) | 7402 (43.8) | 1250 (41.1) | 960 (41.2) | 1098 (48.4) | 0.072 |
| Oxycodone, n (%) | 4491 (26.6) | 788 (25.9) | 573 (24.7) | 471 (20.8) | <0.001 | |
| Tramadol, n (%) | 3734 (22.1) | 757 (24.9) | 581 (25.1) | 507 (22.3) | 0.026 | |
| Hydromorphone, n (%) | 1171 (6.9) | 217 (7.1) | 169 (7.3) | 165 (7.3) | 0.406 | |
| Subsequent opioid prescription filled within 30-days, n (%) | 1033 (6.1) | 160 (5.3) | 117 (5.1) | 94 (4.1) | <0.001 | |
Abbreviation: IQR, interquartile range; MME, morphine milligram equivalent;
suppressed (n<6)
DISCUSSION
In our population-based sample of opioid-naïve adults undergoing four common surgeries, we found age-related patterns of opioid prescriptions filled after surgery that suggested these prescriptions are variably modified due to patient age. For three of the four surgical procedures we assessed, the proportion who filled a postoperative opioid prescription decreased with age. There were also some small shifts in the type of opioid dispensed; our data suggest that, with increasing age, oxycodone becomes less common and codeine and/or tramadol are filled instead (potential explanations include perceptions of lower risk for the latter medications compared to “strong” opioids).2 However, the total MME dose of the initial prescriptions filled showed minimal age-related trends.
Although somewhat contrary to our hypotheses, these findings are perhaps not surprising given the lack of consensus around optimal postoperative opioid prescribing26 and time-pressures for prescribers in this setting; prescribers may be challenged to balance concerns over the safety and effectiveness of opioids against the consequences of potentially undertreating pain in this population and many may rely on standard preprinted prescriptions.
The study provides population-based data on opioid prescriptions filled after surgery. Unlike many other studies of opioid prescribing in surgical populations,16–19 our data were not restricted to a specific age range nor to a subset of opioids prescribed for pain after surgery. Our results likely generalize to other populations, including in the United States, where opioid over-prescribing after surgery is common.26 However, these findings may not extend to other surgical procedures. For example, age-related patterns were less apparent for knee meniscectomies, where older adults also made up a small proportion of the patient population; it is possible that clinicians who typically prescribe for younger patient populations are less likely to incorporate age into prescribing choices for older adults. Still, we recognize that differences in postoperative opioid prescriptions by surgical subspecialty may be attributable to surgical subspecialty practices as well as patient and procedure characteristics.19 Relatedly, the surgical procedures that formed the basis of our cohort may have selected a more robust subset of older adults and so their prescription opioid use patterns may not reflect those of other groups, such as those with cognitive impairment.27
The trends showing older adults were less likely to fill postoperative opioid prescriptions must be interpreted with caution. We could not ascertain opioid prescriptions that were written but not filled and, therefore, could not determine if clinicians were prescribing opioids to older adults less often or if older adults were less likely to accept or fill these prescriptions.28 Also, our study objective was to describe opioid prescriptions filled after surgery and in relation to patient age. As such, we did not carry out adjusted analyses accounting for patient characteristics (e.g., medical and psychiatric comorbidities), concomitant medications (including non-opioid analgesics) or anesthetic technique – all of which might affect postoperative pain and subsequent opioid needs.9 We also could not assess patients’ pain or the quantity of opioids actually consumed, as these data are unavailable. Finally, our measures to define concepts of opioid-naïve and postoperative opioid prescriptions were based on previous research, but other terminology and data definitions have been used in this area of research.16–19
Management of postoperative pain should be tailored to the individual and surgical procedure involved.13 Opioids are an important component of managing pain after surgery but they carry risks, including specifically for older adults.3–5 Clinicians must carefully balance the benefits and risks of prescribing opioids to older adults in the perioperative period. Our data describe postoperative opioid prescriptions filled by opioid-naïve adults after four common surgeries. Our results suggest, in these surgical contexts, that postoperative opioid prescription dosage is not typically altered in older adults. Evidence-based standards would encourage safe and effective postoperative opioid prescribing26 but further research is needed to first establish evidence-based prescribing practices for older adults and then support their implementation.29
Supplementary Material
Key points:
Management of postoperative pain should be tailored to the individual and surgical procedure involved. Opioids are important in this context but they carry risks, including specifically for older adults; when considering opioids for older adults, clinicians may opt to initiate opioids at lower dose.
For three of the four surgical procedures we assessed, the proportion of patients that filled a postoperative opioid prescription decreased with age, however, among those that filled a prescription, there was little evidence of age-related patterns in the initial prescription’s dose.
Our descriptive data suggest postoperative opioid prescription dosage is not typically different in older adults.
ACKNOWLEDGEMENTS
This study was funded by the National Institute on Drug Abuse, National Institutes of Health (grant number: 1R01DA042299-01A1 to HW, BB, MDN, and DNW). This study was supported by ICES, which is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care (MOHLTC). The opinions, results and conclusions reported in this paper are those of the authors and are independent from the funding sources. No endorsement by ICES or the Ontario MOHLTC is intended or should be inferred. Parts of this material are based on data and/or information compiled and provided by the Canadian Institute for Health Information (CIHI). However, the analyses, conclusions, opinions and statements expressed in the material are those of the author(s), and not necessarily those of CIHI. We thank IMS Brogan Inc for use of their Drug Information Database. Dr. Wunsch is supported by an Excellence in Research Award from the Department of Anesthesia at the University of Toronto. Dr. Wijeysundera is supported in part by a New Investigator Award from the Canadian Institutes of Health Research, an Excellence in Research Award from the Department of Anesthesia at the University of Toronto, and the Endowed Chair in Translational Anesthesiology Research at St. Michael’s Hospital and University of Toronto. Dr. Ladha is support by a Merit Award from the Department of Anesthesia at the University of Toronto. The study sponsors had no role in study design, in the collection, analysis and interpretation of data, in the writing of the report and in the decision to submit the report for publication.
Footnotes
Conflict of Interest: Dr. Bateman has received grants from Eli Lilly and Company, GlaxoSmithKline, Pacira, Baxalta, and Pfizer to the Brigham and Women’s Hospital for unrelated work, served as a consultant to Aetion and received personal fees from Alosa Foundation. The other authors declare no competing interests.
REFERENCES
- 1.Moriya AS and Miller GE Any Use and Frequent Use of Opioids among Elderly Adults in 2015–2016, by Socioeconomic Characteristics. September 2018. Statistical Brief #515. Agency for Healthcare Research and Quality, Rockville, MD: https://meps.ahrq.gov/mepsweb/data_files/publications/st515/stat515.pdf. Accessed March 13, 2019. [Google Scholar]
- 2.Canadian Institute for Health Information. Pan-Canadian Trends in the Prescribing of Opioids, 2012 to 2016. https://secure.cihi.ca/free_products/pan-canadian-trends-opioid-prescribing-2017-en-web.pdf. Accessed March 13, 2019.
- 3.Dowell D, Haegerich TM, Chou R. CDC Guideline for Prescribing Opioids for Chronic Pain — United States, 2016. MMWR Recomm Rep. 2016;65: 1–49. [DOI] [PubMed] [Google Scholar]
- 4.Chau DL, Walker V, Pai L, Cho LM. Opiates and elderly: use and side effects. Clin Interv Aging. 2008;3: 273–278. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Falzone E, Hoffmann C, Keita H. Postoperative Analgesia in Elderly Patients. Drugs Aging. 2013;30: 81–90. [DOI] [PubMed] [Google Scholar]
- 6.Commonwealth of Pennsylvania and the Pennsylvania Medical Society. Prescribing Guidelines for Pennsylvania. Geriatric Pain. Opioid Use and Safe Prescribing https://www.health.pa.gov/topics/Documents/Opioids/OpioidGuidelinesGeriatrics.pdf. ccessed July 31, 2019.
- 7.Galicia-Castillo M Opioids for persistent pain in older adults. Cleve Clin J Med. 2016;83: 443–51. [DOI] [PubMed] [Google Scholar]
- 8.Gupta DK, Avram MJ. Rational opioid dosing in the elderly: dose and dosing interval when initiating opioid therapy. Clin Pharmacol Ther. 2012;91: 339–43. [DOI] [PubMed] [Google Scholar]
- 9.Davies PS. Opioids for pain management in older adults: Strategies for safe prescribing. Nurse Pract. 2017;42: 20–26. [DOI] [PubMed] [Google Scholar]
- 10.Tracy B, Sean Morrison R. Pain management in older adults. Clin Ther. 2013;35: 1659–68. [DOI] [PubMed] [Google Scholar]
- 11.Shah A, Hayes CJ, Martin BC. Factors Influencing Long-Term Opioid Use Among Opioid Naive Patients: An Examination of Initial Prescription Characteristics and Pain Etiologies. J Pain. 2017;18: 1374–1383. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Pasricha SV, Tadrous M, Khuu W, et al. Clinical indications associated with opioid initiation for pain management in Ontario, Canada: a population-based cohort study. Pain. 2018;159: 1562–1568. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Chou R, Gordon DB, de Leon-Casasola OA, et al. Management of Postoperative Pain: A Clinical Practice Guideline From the American Pain Society, the American Society of Regional Anesthesia and Pain Medicine, and the American Society of Anesthesiologists’ Committee on Regional Anesthesia, Executive Committee, and Administrative Council. J Pain. 2016;17: 131–57. [DOI] [PubMed] [Google Scholar]
- 14.Mohanty S, Rosenthal RA, Russell MM, Neuman MD, Ko CY, Esnaola NF. Optimal Perioperative Care of the Geriatric Patient. https://www.facs.org/-/media/files/quality-programs/geriatric/acs-nsqip-geriatric-2016-guidelines.ashx?la=en. Accessed July 5, 2019. [DOI] [PubMed]
- 15.Ip HYV, Abrishami A, Peng PWH, Wong J, Chung F. Predictors of Postoperative Pain and Analgesic Consumption: A Qualitative Systematic Review. Anesthesiology. 2009;111: 657–677. [DOI] [PubMed] [Google Scholar]
- 16.Alam A, Gomes T, Zheng H, Mamdani MM, Juurlink DN, Bell CM. Long-term Analgesic Use After Low-Risk Surgery: A Retrospective Cohort Study. Arch Intern Med. 2012;172: 425–430. [DOI] [PubMed] [Google Scholar]
- 17.Clarke H, Soneji N, Ko DT, Yun L, Wijeysundera DN. Rates and risk factors for prolonged opioid use after major surgery: population based cohort study. BMJ. 2014;348: g1251. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Brummett CM, Waljee JF, Goesling J, et al. New persistent opioid use after minor and major surgical procedures in us adults. JAMA Surg. 2017;152: e170504. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Bicket MC, Murimi IB, Mansour O, Wu CL, Alexander GC. Association of new opioid continuation with surgical specialty and type in the United States. Am J Surg. 2019. April 15 pii: S0002–9610(19)30127–8. [DOI] [PubMed] [Google Scholar]
- 20.Health care in Ontario. Ontario Drug Benefit program. Check medication coverage. 2019. https://www.ontario.ca/page/check-medication-coverage/ Accessed January 5, 2019.
- 21.Ladha KS, Neuman MD, Broms G, et al. Opioid Prescribing After Surgery in the United States, Canada, and Sweden. JAMA Netw Open. 2019;2: e1910734. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Ontario Ministry of Health and Long-Term Care. Narcotics Monitoring System (NMS) Pharmacy Reference Manual 2012. http://www.health.gov.on.ca/en/pro/programs/drugs/resources/narcotics_manual.pdf. Accessed January 5, 2019.
- 23.Brat GA, Agniel D, Beam A, et al. Postsurgical prescriptions for opioid naive patients and association with overdose and misuse: retrospective cohort study. BMJ. 2018;360: j5790. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Centers for Medicare & Medicaid Services. Opioid Oral Morphine Milligram Equivalent (MME) Conversion Factors. https://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovContra/Downloads/Opioid-Morphine-EQ-Conversion-Factors-Aug-2017.pdf. Accessed June 5, 2018.
- 25.Health Quality Ontario. Opioid Prescribing for Acute Pain Care for People 15 Years of Age and Older. https://www.hqontario.ca/portals/0/documents/evidence/quality-standards/qs-opioid-acute-pain-clinician-guide-en.pdf. Accessed June 5, 2019.
- 26.Neuman MD, Bateman BT, Wunsch H. Inappropriate opioid prescription after surgery. Lancet. 2019;393: 1547–1557. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Feldt KS, Ryden MB, Miles S. Treatment of Pain in Cognitively Impaired Compared with Cognitively Intact Older Patients with Hip-Fracture. J Am Geriatr Soc. 1998;46: 1079–1085. [DOI] [PubMed] [Google Scholar]
- 28.Lin JJ, Alfandre D, Moore C. Physician Attitudes Toward Opioid Prescribing for Patients With Persistent Noncancer Pain. Clin J Pain. 2007;23. [DOI] [PubMed] [Google Scholar]
- 29.Wetzel M, Hockenberry J, Raval MV. Interventions for postsurgical opioid prescribing: A systematic review. JAMA Surg. 2018;153: 948–954. [DOI] [PubMed] [Google Scholar]
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