Overprescription of Opioids Following Outpatient Anorectal Surgery: A Single Institution Study

Abstract

BACKGROUND:

Surgeons contribute to the opioid epidemic by overprescribing opioids for postoperative pain. Excess, unused opioids may be diverted for misuse/abuse.

OBJECTIVE:

To characterize opioid prescribing and use among patients undergoing outpatient anorectal procedures and to assess adequacy of postoperative pain management.

DESIGN:

Retrospective cohort study, prospective cross-sectional survey.

SETTINGS:

Patients treated by colorectal surgeons in an academic medical center between January 2018-September 2019.

PATIENTS:

627 patients who underwent an outpatient anorectal procedure were included.

MAIN OUTCOME MEASURES:

Opioids prescribed at discharge, opioid prescription refills, patient reported outcomes regarding opioid use and adequacy of postoperative pain management in terms of pain intensity and pain interference. Opioids were standardized to 5mg oxycodone pills. Patient reported outcomes were assessed using previously validated instruments.

RESULTS:

The majority of patients underwent fistula surgery (n=234) followed by exam under anesthesia (EUA; n=183), hemorrhoidectomy (n=131), incision and drainage (I&D) (n=51),and pilonidal excision (n=28). Most patients received opioids (78% fistula, 49% EUA, 87% hemorrhoidectomy, 71% I&D, 96% pilonidal). EUAs received the fewest opioid pills (median 10, range 3-50) followed by fistula (median13, range 1-50), I&Ds (median 15, range 3-120), pilonidals (median 15, range 3-60) and hemorrhoidectomies (median 28, range 3-60). Regardless of procedure, the majority of patients used less than five opioid pills postoperatively. Pilonidal patients had the largest number of excess unused pills (median 14, range 0-30) followed by fistula and I&D (median 7, ranges 0-30 and 5-17, respectively), hemorrhoidectomy (median 6, range 0-50) and EUA (median 2, range 0-23). While hemorrhoidectomy patients reported higher pain levels following discharge, most reported minimal interference with day to day activities due to pain regardless of procedure performed.

LIMITATIONS:

Recall bias, sample bias.

CONCLUSIONS:

The majority of patients do not need more than five to ten 5mg oxycodone equivalents to achieve adequate pain management after outpatient anorectal surgical procedures. See Video Abstract at http://links.lww.com/DCR/B347

INTRODUCTION

The United States is in the midst of a deadly opioid epidemic. The death rate for opioid overdoses has more than quadrupled from 2000 to 2016, culminating in over 60,000 deaths attributable to opioids in 2016 alone.¹ It is estimated that over 11.8 million people in the US misused opioids during 2016 – accounting for 4.4% of the total US population over the age of 12.² Over-prescription of opioids by physicians is a major contributor to the epidemic as it provides the opportunity for misuse or diversion of opioids by patients and others in the community. In 2017, US physicians wrote greater than three times more prescriptions for opioids than they did in 1999.³

Surgeons contribute to the opioid epidemic by overprescribing opioids to treat post-operative pain. Recent studies have found that, as a whole, surgeons often prescribe more opioids than are needed to manage postoperative pain after discharge.^4-6 These unused opioids remain in the community available for misuse as patients generally do not dispose of them appropriately.^6,7 Guidelines on standardized postoperative opioid prescriptions for common general surgery procedures were recently published and their implementation has been shown to decrease the amount of opioids prescribed.^8,9 To date, little work has examined opioid prescribing habits and use in the colorectal surgical population. Outpatient anorectal procedures, such as hemorrhoid or anal fistula surgeries, are commonly performed in colorectal surgical practice and anecdotally it is standard practice for patients to be discharged with an opioid prescription. A 2018 study found that over 70% of opioid pills prescribed to patients undergoing anorectal procedures went unused, however this study only included 42 patients.¹⁰

We sought to characterize patterns of postoperative opioid prescribing and use among patients undergoing outpatient anorectal procedures with colorectal surgeons at our institution. In addition, we evaluated post-discharge use of opioids by patients and assessed the adequacy of pain management after discharge using previously validated patient reported outcome measures assessing pain intensity and interference of pain with daily activities. The overall goal of our study was to inform ongoing efforts to reduce excess postoperative opioid prescribing while ensuring adequate post-discharge pain management.

METHODS

Study population

We evaluated opioid prescribing and use among adult patients who underwent an outpatient anorectal procedure performed by one of six staff colorectal surgeons at the University of Wisconsin between January 2018 and September 2019. Anorectal procedures were defined as anorectal fistula surgeries, incision and drainage (I&D) of anorectal abscess, excisional hemorrhoidectomy, exam under anesthesia (EUA) with or without biopsies, and excision of pilonidal disease. The patient reported outcomes survey was administered at the postoperative clinic visit. Preliminary analyses indicated that over 85% of the patients undergoing outpatient anorectal procedures came to their postoperative clinic visit at our institution. This study was determined to be quality improvement and exempt from institutional review board (IRB) oversight by the University of Wisconsin Health Sciences IRB.

Postoperative analgesia

It is standard of care in our colorectal surgery group for patients undergoing anorectal procedures (with the exception of EUAs) to receive a field block of local anesthesthetic. Extended release local anesthestics, such as liposomal bupivacaine, are not curently approved for this indication in our institution and thus were not administered to any patients included in this study. While gabapentin is frequently used for inpatients, it is not routinely administered for outpatient procedures such as those included in this study. A one-time dose of Toradol is administered postoperatively by anesthesia on a case by case basis. Of the patients included in this study, 33% received Toradol. Postoperatively, all patients undergoing an anorectal procedure were counselled to take daily and as needed sitz baths as well as scheduled acetaminophen alternating with ibuprofen unless contraindicated due to other medical conditions. Patients were also advised to use heat and/or ice packs for symptom relief as needed. Finally, patients were instructed to take opioids as needed for pain that was not adequately managed using the above methods. Opioids were prescribed by a resident or attending physician.

Data collection and survey administration

Prospective data abstraction was performed by automated data abstraction as well as manual chart review of the electronic medical record (EMR) for all patients in the study. We abstracted basic demographic and clinical information, details of the surgical procedure performed, and information regarding postoperative opioid prescriptions written at discharge as well as refills. Patients with three or more active opioid prescriptions in the six months prior to surgery were classified as chronic opioid users in our analysis. Patients who received additional opioid prescriptions in the 30 days following surgery were classified as having received a refill. Generally refills are prescribed by advance practice providers in the colorectal surgery clinic during working hours and by in-house resident physicians on nights and weekends. Due to the way refill data was collected, patients who received opioid prescriptions within 30 days of surgery from the Emergency Department or other physicians who used the UW Health electronic medical record were recorded as having had a refill prescribed.

Patients were queried about their postoperative opioid usage, pain intensity, and how much pain interfered with their daily activities at their first postoperative clinic visit beginning in April 2018, usually at 3 weeks postoperatively. A previously described survey instrument was used to determine whether patients filled their opioid prescription and how many opioid pills patients used after discharge.⁴ Briefly, patients were asked if they took any opioid pills after coming home from the hospital and were given the options of none, very few (less than 5 pills taken), about half of all pills, nearly all (less than 5 pills left) or all pills. We used previously validated measures from the Patient Reported Outcomes Measurement Information System (PROMIS®) to assess pain intensity (PROMIS Item Bank v.1.0 – Pain Intensity – Scale) and pain interference with daily activities (PROMIS Item Bank v.1.0 – Pain Interference – Short Form 4a).¹¹ Surveys were administered verbally to 10% of the study population by medical assistants (MAs) in the colorectal surgery clinic and responses entered into the EMR. The total population of patients was not surveyed due to logistical difficulties related to staffing. All colorectal surgery clinic MAs were trained in administration of the surveys however inconsistent availability of medical assistants, high staff turnover and use of float medical assistants from non-colorectal surgery clinics meant that the surveys were often not administered. No patients were specifically included or excluded from survey participation and no patient refused to answer the survey.

Analysis and Statistics

The total number of opioid pills used was calculated based on survey responses: zero pills = “none,” 5 pills = “very few (<5 pills taken),” total number of pills prescribed divided by two = “about half,” total number of pills prescribed minus 5 = “almost all (<5 pills remaining),” and total number of pills prescribed = “all.” Patients who were prescribed less than five pills and reported taking “very few” or “almost all” pills were considered to have taken all of their prescribed pills. The number of excess pills for each patient was calculated by subtracting the calculated number of pills used from the total number of pills prescribed. Opioid quantities were converted to an eqianalgesic equivalent (1 pill=5mg oxycodone) to allow comparisons between patients who received different opioid formulations.¹²

Descriptive statistics were performed using STATA v. 15.1.

RESULTS

A total of 627 patients were included in this study (Figure 1). Just over half of the patients were male (57%, Table 1). The majority of patients underwent fistula surgery (37%), followed by EUA (29%), excisional hemorrhoidectomy (21%), I&D (8%) and pilonidal excision (4%). Patients undergoing I&Ds or fistula procedures had the highest rate of preoperative opioid use (47% and 45% respectively) followed by patients undergoing EUA (28%) and excisional hemorrhoidectomy or pilonidal excision (both 7%). The indications for these procedures are listed in Table 1.

Figure 1:

Flow diagram of study participants.

Table 1:

Demographics and postoperative opioid prescriptions for patients undergoing outpatient anorectal procedures

Variables	Fistulotomy/ Sphincterotomy/Seton (N=234)		Abscess Drainage (N=51)		Hemorrhoid (N=131)		EUA (N=183)		Pilonidal (N=28)		p-value
	n	Summary	n	Summary	n	Summary	n	Summary	n	Summary
Age	234	44.2±13.9	51	44.3±12.6	131	50.0±13.5	183	49.6±13.6	28	28.1±8.2	<0.01a
Male	234	134 (57)	51	26 (51)	131	69 (53)	183	105 (57)	28	23 (82)	0.06c
Chronic Opioid Use	234		51		131		183		28		<0.01c
. Yes		43 (18.4)		13 (25.5)		3 (2.3)		17 (9.3)		0 (0.0)
. No		191 (81.6)		38 (74.5)		128 (97.7)		166 (90.7)		28 (100.0)
Indication	234		51		131		183		28		<0.01c
. Fistula		154 (66)		2 (4)		0 (0)		0 (0)		0 (0)
. Fissure		22 (9.)		1 (2)		0 (0)		27 (15)		0 (0)
. Abscess		27 (12)		25 (49)		0 (0)		4 (2)		0 (0)
. IBD		24 (10)		17 (33)		0 (0)		10 (6)		1 (4)
. Anal Dysplasia		0 (0)		0 (0)		1 (1)		69 (38)		0 (0)
. Pilonidal Disease		0 (0)		0 (0)		0 (0)		0 (0)		27 (96)
. Hemorrhoids		1 (0.4)		0 (0)		117 (89)		1 (1)		0 (0)
. Rectal Polyp		0 (0)		0 (0)		4 (3)		4 (2)		0 (0)
. Condyloma		0 (0)		0 (0)		0 (0)		16 (9)		0 (0)
. Stenosis		2 (1)		0 (0)		0 (0)		4 (2)		0 (0)
. Other		4 (2)		6 (12)		9 (7)		48 (26)		1 (1)
Opioid Rx	234	183 (78)	51	36 (71)	131	114 (87)	183	90 (49)	28	27 (96)	<0.01c
Opioid Prescribed	184		36		114		91		28		<0.01c
. Oxycodone		71 (38.6)		20 (55.6)		66 (57.9)		53 (58.2)		12 (42.9)
. Oxycodone/Acetaminophen		29 (15.8)		2 (5.6)		20 (17.5)		5 (5.5)		3 (10.7)
. Hydrocodone/Acetaminophen		79 (42.9)		10 (27.8)		28 (24.6)		33 (33.3)		13 (46.4)
. Morphine		0 (0.0)		1 (2.8)		0 (0.0)		0 (0.0)		0 (0.0)
. Tramadol		5 (2.7)		3 (8.3)		0 (0.0)		0 (0.0)		0 (0.0)
5mg Oxycodone Eq.	183		36		114		90		27
. Mean±SD		16.1±9.9		19.1±19.5		26.8±14.3		13.5±9.5		18.1±10.8	<0.01a
. Median (range)		13.3 (1-50)		15.0 (3-120)		28.3 (3-60)		10.0 (3-50)		15.0 (3-60)
Refill Needed	234	40 (17)	51	16 (31)	131	30 (23)	183	19 (10)	28	9 (32)	<0.01c

Values presented as Mean ± SD or N (column %).

p-values:

^a=Anova

^c=Pearson's chi-square test.

Most patients received a postoperative opioid prescription. Rates varied from 96% of patients undergoing pilonidal excision to 49% of patients undergoing EUA, with patients undergoing hemorrhoidectomy, fistula procedures and I&Ds in between (87%, 78% and 71%, respectively). Of patients who received opioid prescriptions, hemorrhoidectomy patients had the highest number of pills prescribed (median 28, range 3-60) followed by I&Ds (median 15, range 3-120), pilonidal excision (median 15, range 3-60), fistula procedures (median 13, range 1-50), and EUA (median 10, range 3-50). The type of opioids prescribed are listed in Table 1. There was a wide variation in the number of pills prescribed to patients undergoing each procedure, as shown in Fig 2a. About one third of patients undergoing pilonidal excision or I&Ds received a refill of their postoperative opioid prescription, followed by 23% for excisional hemorrhoidectomy, 17% for fistula procedures, and 9% for EUA (Table 1).

Figure 2:

Opioid prescription and usage in patients undergoing common outpatient anorectal procedures.

A. Total number of opioid pills prescribed at discharge for patients undergoing listed outpatient anorectal procedures. B. Total number of opioid pills used as reported by patients at first postoperative clinic visit. C. Total number of excess opioid pills for each patient was calculated by subtracting patient reported pills used from total pills prescribed. Opioid pills in A-C were all converted to and reported as 5mg oxycodone equivalents. I&D: Incision and drainage; EUA: Exam under anesthesia.

With the exception of patients undergoing EUAs, the majority of patients surveyed reported using opioids after discharge (Table 2). Overall, patients undergoing fistula procedures, I&Ds and excisional hemorrhoidectomy used the most opioids with a median of 5 pills (ranges 0-45, 0-11.7, and 0-40 respectively), followed by EUA with 3 pills (range 0-13) and pilonidal with 2.5 pills (range 0-30). Regardless of the type of surgical procedure performed, over 50% of all patients reported using five or fewer opioid pills after discharge (Fig 2b).

Table 2:

Patient reported opioid usage and calculated number of excess pills^a

Outcomes	Fistulotomy/ Sphincterotomy/Set on (N=35)		Abscess Drainage (N=6)		Hemorrhoid (N=21)		EUA (N=20)		Pilonidal (N=4)		p-value
	n	Summary	n	Summary	n	Summary	n	Summary	n	Summary
Patients Who Took Opioids	35	21 (60)	6	4 (66)	21	15 (71)	20	7 (35)	4	3 (75)	0.36c
Pills Used	29		5		20		9		4		0.68b
. Mean ± SD		8.6±12.2		4.3±4.8		8.7±11.3		4.4±5.3		3.7±4.8
. Median (range)		5.0 (0-45)		5.0 (0-11.7)		5.0 (0-40)		3.3 (0-13.3)		2.5 (0-10)
Excess Prescription	29		5		20		9		4
. Mean ± SD		10.4±8.6		9.0±5.1		12.7±13.1		4.4±7.5		14.6±13.1	0.50b
. Median (range)		6.7 (0-30)		6.7 (5-16.7)		5.8 (0-50)		1.7 (0-23)		14.2 (0-30)

^a:Opioid pills reports at 5mg oxycodone equivalents Values presented as Mean ± SD or N (column %).

p-values:

^b=Anova

^c=Pearson's chi-square test.

The distribution of excess unused pills across patients and procedure types is shown in Fig 2c. Overall, patients undergoing pilonidal excision had the most excess unused pills (median 14, range 0-30) followed by fistula procedures (median 6.7, range 0-30), I&Ds (median 6.7, range 5-16.7), hemorrhoidectomy (median 5.8, range 0-50), and EUA (median 1.7, range 0-23) (Table 2).

On average, most patients reported no or mild postoperative pain (Fig 3). Two patients undergoing EUA (10%) reported their average pain as being severe or very severe. In addition, there was one patient who underwent pilonidal excision (25%) one patient who underwent a fistula procedure (3%) and one I&D patient (25%) that reported severe pain. No patient undergoing excisional hemorrhoidectomy reported more than moderate average postoperative pain (Fig 3).

Figure 3:

Average postoperative pain for patients undergoing common outpatient anorectal procedures. Patients who had undergone the listed outpatient anorectal procedures were queried about their average postoperative pain level at their postoperative clinic visit using PROMIS pain scores. I&D: Incision and drainage; EUA: Exam under anesthesia.

A higher proportion of patients undergoing excisional hemorrhoidectomy (90%) reported that postoperative pain interfered in their daily activities compared to patients undergoing I&Ds (83%), fistula procedures (57%), EUA (50%) or pilonidal excision (50%) (Fig. 4). All patients undergoing pilonidal excision reported either no or little interference of pain in their daily activities. Patients undergoing excisional hemorrhoidectomy were the least likely to report either no or little interference of pain in their daily activities (34%), followed by I&D (50%), fistula procedures (69%) and EUA (70%).

Figure 4:

Postoperative pain interference with daily activities in patients undergoing common outpatient anorectal procedures. Patients who had undergone the listed outpatient anorectal procedures were queried about how much their postoperative pain interfered with their daily activities at their postoperative clinic visit using a PROMIS survey. I&D: Incision and drainage; EUA: Exam under anesthesia.

DISCUSSION

There is increasing evidence that surgeons contribute to the opioid epidemic through unnecessary overprescribing of opioids after surgical procedures. Our study adds to the growing literature on this subject by focusing on opioid prescribing after commonly performed outpatient anorectal procedures. We found wide variation in the number of pills prescribed between the four procedures examined, as well as within each procedure. Overall, surgeons overprescribed opioids to this population, with the majority of patients reporting taking fewer than five pills after surgery, regardless of procedure performed, despite patients bring prescribed between 6-30 pills, on average. As a result, 78% of patients undergoing outpatient anorectal procedures were left with unused, excess pills. Notably, this includes all patients that underwent pilonidal excision and 95% of patients undergoing excisional hemorrhoidectomy. This study also demonstrates that overall patients had adequate postoperative pain control with minimal interference with their everyday activities.

Our finding that surgeons overprescribe opioids to patients following anorectal procedures is not unexpected. Surgeons from all specialties routinely prescribe more opioids than patients actually require.^5,7,10,13-17 A recent paper from Swarup and colleagues specifically focused on patients undergoing anorectal procedures in a single institution and found that on average 84% of opioids prescribed to this population went unused. Our study builds on their findings with an increased sample size and by including patients with a history of opioid use prior to surgery (who were excluded from the previous study). In the six months leading up to surgery, 18% of the fistula, 26% of the I&D and 9% of the EUA patients in our study had three or more active prescriptions for opioids. This finding is notable as there is evidence that preoperative opioid use is associated with increased postoperative use following other surgical procedures.¹⁸ In addition, we included patients undergoing EUA in our study, a procedure that generally does not require much postoperative analgesia. Indeed, patients undergoing EUA in our study had the fewest number of pills prescribed compared to the other procedures studied.

Our study additionally builds on prior published work by assessing functional pain scores in the context of postoperative opioid prescribing, rather than relying on numeric pain scales to evaluate adequacy of analgesia. Numeric pain scales have poor inter-rater reliability at the individual level. For example, at a pain level of 7 some patients may be unable to get out of bed while others may be able to run errands and go to work. When assessing recovery after surgery, the absolute number on the pain scale is not as clinically relevant as how a patient’s postoperative pain impacts their ability to move and perform their activities of daily living.¹⁹ We believe that asking patients about whether their pain impacts their activities more accurately evaluates the adequacy of postoperative analgesia. Notably, the majority of patients in our study reported minimal interference of postoperative pain on their daily activities. Of all patients included, those undergoing excisional hemorrhoidectomy were most likely to report that pain interfered “somewhat” or “a little bit.” Nevertheless, most surgeons would not recommend opioids as a first line treatment for pain that only minimally interferes with activities.

There is an apparent contradiction in the relatively high refill rate (10-32% depending on procedure) and the high percentage of patients who had excess pills. Some of this likely relates to how opioid refill data were collected, any patient who received an additional opioid prescription within 30 days of surgery were classified as receiving a refill. It is possible that some of these “refills” were not actually for postoperative pain as we do not know the indication for the prescription. Additionally, we did not exclude patients with chronic opioid use from our study and these patients had a much higher refill rate than patients who were not receiving opioids prior to surgery (41% vs 15% respectively, p<0.01, data not shown). Finally, electronic prescription of opioids is available in Wisconsin making refill prescriptions much easier for both providers and patients.

This study adds to the growing mountain of data demonstrating that surgeons prescribe too many opioids that patients do not use.^5,7,10,13-17 Overprescribing opioids does not just lead to additional pills in the community available for misuse or abuse, but also likely contributes to overuse by patients. A recent study demonstrated that as patients were prescribed more opioid pills postoperatively, they used more.¹⁷ Thus, the available data would suggest that the surgeon’s habit of prescribing extra opioids “just in case” is not a service to the patient and may lead to harm of the patient and community.

Given our findings, it seems likely that postoperative opioid use could be reduced further. Multimodal analgesic approaches could be employed that rely more on regional blocks and non-opioid pain relievers such as acetaminophen and ibuprofen.^20-22 In addition, improved patient education is needed to set expectations regarding management of postoperative pain as well as when opioids are appropriate to take.²³ Further study is needed to identify effective interventions for reducing dependence on opioids for postoperative pain management.

This study has several limitations. This is a single institution study and the results may not be applicable to other populations. Our data on opioid use as well as the pain and functional scores may not be representative of the study population as a whole as we were unable to administer our survey to all patients at their postoperative visit due to limited availability of personnel and time constraints. However, we believe the risk of sample bias is low as patients were not excluded systematically and no patients refused to answer the survey. A significant number of our patients were not naïve to opioids at the time of surgery. While many of these patients had likely received opioids due to their disease process, patients undergoing multiple fistula procedures for example, we are unable to assess the indications for these prescriptions. Additionally, while we did encourage opioids to be used only if acetaminophen or ibuprofen were ineffective, we do not know what non-opioid regimes patients were utilizing at home. Regarding refills, we do not know if any patients obtained refills outside of the UW Health system. Finally, postoperative opioid use was self-reported and may be subject to recall bias.

Overall, this study demonstrates that patients undergoing outpatient anorectal procedures receive more opioid pills than they need at discharge and that their pain is fairly well controlled. While every patient has different postoperative analgesia needs and should be evaluated on an individual basis, our data suggests that the majority of patients undergoing EUAs likely do not need any opioids postoperatively and fistula, abscess drainage, hemorrhoid or pilonidal patients do not need more than five or ten 5mg oxycodone equivalents. By bringing prescription habits more in line with patient needs, surgeons can help prevent our patients from joining the millions impacted by the opioid epidemic.