Opioid Use Among Veterans Undergoing Major Joint Surgery Managed by a Multidisciplinary Transitional Pain Service

Abstract

Background:

Chronic post-surgical pain and opioid use is a problem among patients undergoing many types of surgical procedures. A multidisciplinary approach to perioperative pain management known as a Transitional Pain Service (TPS) may lower these risks.

Methods:

This retrospective cohort study was conducted at the Salt Lake City VA Medical Center to compare patients undergoing elective primary or revision total knee, hip, or shoulder replacement or rotator cuff repair in the year before (2017) and after (2018) implementation of a TPS. The primary outcome is the proportion of patients taking opioids 90-days after surgery. Secondary outcomes include new-chronic opioid use after surgery as well as the proportion of previous chronic opioid users who stopped or decreased opioid use after surgery.

Results:

At 90 days after surgery, patients enrolled in TPS were significantly less likely to be taking opioids (13.4%-TPS vs 27.3%-pre-TPS; P=0.002). This relationship remained statistically significant in a multivariable logistic regression analysis where the TPS group had 69% lower odds of post-operative chronic opioid use compared to the pre-intervention group (OR:0.31;95%CI:0.14-0.66; P=0.03). Opioid naïve patients enrolled in TPS were less likely to have new chronic opioid use after surgery (0.7%-TPS vs 8.4%-pre-TPS; P=0.004). Further, patients enrolled in TPS with existing chronic opioid use prior to surgery were more likely to reduce or completely stop opioid use after surgery (67.5%-TPS vs 45.3%-pre-TPS; P=0.037) as compared to pre-TPS.

Conclusions:

These data suggest that a TPS is an effective strategy for preventing new chronic opioid use and reducing overall opioid use following orthopedic joint procedures in a VA hospital.

Introduction

Despite many advances over the past decade, perioperative pain management strategies continue to be inadequate for a high percentage of surgical patients. Ranges from 10-49% have been reported for patients experiencing chronic post-surgical pain (CPSP)^1–5, which is defined generally as pain in the surgical area that lasts beyond the expected time frame of surgical healing. Analgesic therapies are often only marginally effective, and/or have significant deleterious effects associated with them. Consequently, as many as 14% of previously opioid naïve patients go on to develop chronic opioid use after surgery^6–13.

Historically, perioperative pain management has fallen primarily under the direction of the surgical team whereby pain management is discussed briefly with the patient, but typically without any standardized education or coordination with primary care providers after surgery. When patients have ongoing surgical pain beyond the normal follow-up period, primary care and emergency room providers are frequently tasked with deciding whether to continue opioids and other pain medications. Together, these factors can lead to fragmentation of perioperative pain management and inappropriate continuation of opioid medications.

One solution to address fragmentation of perioperative pain management is to deliver opioid education, risk modification, cognitive-behavioral therapy, and prescribing recommendations by a single transitional pain service (TPS). This type of multidisciplinary pain approach has been previously described, although other TPS programs have not been designed to engage surgical patients beginning in the preoperative period^14–16. In 2018, we designed and implemented a novel TPS at the Salt Lake City VA Medical Center (SLC VAMC) that engages at-risk patients starting in the preoperative period and follows them until up to six months after surgery. The goals of this TPS are to: 1) reduce pain suffering through education, risk modification, cognitive interventions, and optimization of pharmacologic and non-pharmacologic therapy, 2) eliminate the development of new chronic opioid use after surgery, and 3) assist prior chronic opioid users to decrease or completely taper off opioid use after surgery.

This study was designed to evaluate whether implementation of a TPS would reduce opioid use among veterans undergoing major joint surgery, a patient population at high risk for CPSP¹⁷. We hypothesized that a multidisciplinary approach to pain management would decrease fragmentation during care transitions and significantly reduce opioid use after orthopedic surgery for both chronic opioid users and opioid naïve patients.

Methods

TPS Intervention

The TPS intervention consists of comprehensive pain management and care coordination delivered by a multidisciplinary team. This team is made up of anesthesiologists with specialization in acute pain management, nurse practitioners with experience in both acute and chronic pain management, nurse care coordinators, and a psychologist. These multidisciplinary providers work together as an integrated team to deliver comprehensive pain management for any surgical patient at risk for CPSP and chronic opioid use. Patients are eligible for TPS engagement based on presence of individual risk factors such as a history of substance use disorder or chronic opioid use, or if they are undergoing a surgical procedure such as total joint replacement associated with a high-risk for CPSP¹⁷. TPS engagement of these patients occurs during all three main phases of a surgical episode of care: 1) the preoperative period, 2) the surgical hospitalization, and 3) postoperative recovery period up to 6 months.

(1). Preoperative Period:

Patients are identified for enrollment in TPS at the time they are scheduled for elective surgical procedures. A TPS nurse contacts each patient before surgery and performs a directed history including mental health diagnoses, pain history, opioid use history, and baseline patient-reported pain measures using Patient Reported Outcome Measurement Information System (PROMIS) instruments as well as pain catastrophizing scale (PCS) scores¹⁸. Patients receive preoperative education either through a 1-hour surgical expectations class or one-on-one visit where topics such as pain after surgery, analgesic strategies, appropriate use of opioids, and non-pharmacologic pain coping strategies are discussed. Individual sessions with a psychologist are also offered prior to surgery with a focus on Mindfulness-Based Intervention (MBI), and Acceptance and Commitment Therapy (ACT). All patients are then reviewed by the anesthesiologist and nurse practitioner prior to surgery to develop individualized plans for perioperative pain management. This may include a discussion with the patient regarding preoperative opioid taper, opioid free surgery and recovery, buprenorphine strategy, or other multimodal analgesic techniques such as peripheral nerve blocks. Any changes for opioid taper or buprenorphine use is discussed directly and done in coordination with the prescribing provider.

(2). Surgical Hospitalization Period:

Individualized pain management plans and Enhanced Recovery After Surgery (ERAS) protocols are implemented including preoperative NSAID, acetaminophen, and gabapentinoid, local infiltrative anesthesia (LIA) by the surgeon, and regional anesthesia where appropriate. Post-operative scheduled acetaminophen, NSAID, and gabapentinoid were provided with breakthrough opioids as needed for post-operative analgesia. Daily rounds are conducted on hospitalized patients by the multidisciplinary TPS team and any new pain management recommendations are made to the surgical team to include discharge medications and opioid taper plan. During their in-hospital stay, patients are offered individual sessions with a psychologist on a daily basis or more frequently for mindfulness meditation and/or relaxation techniques.

(3). Postoperative Period:

Follow-up telephone calls are made by the TPS nurse at post-discharge days 2, 7, 10, 14, 21, 28, and at least monthly until 6 months postoperative. During each call, twenty-four-hour morphine equivalent daily dose (MEDD), PROMIS scores, date of last opioid use, and number of opioid tabs remaining after date of last opioid use are recorded. Outpatient sessions with the psychologist are offered with a continuation of ACT Matrix and MBI used as well as assessment and referral for appropriate long-term mental health services. The anesthesiologist and nurse practitioner provide opioid taper support and prescribe alternative analgesic therapies when needed. Any change in medications is done through close communication and coordination with the surgical team, primary care, mental health and/or chronic pain providers. For patients with chronic pain and chronic opioid use, transition to a chronic pain team is offered and facilitated.

TPS Implementation

The TPS intervention as described above was implemented at the VA Salt Lake City Medical Center in January 2018 as a one-year pilot. During this pilot period, we enrolled all patients scheduled to undergo primary or revision total knee, hip, or shoulder surgery or rotator cuff surgery based on the established risk of CPSP and opioid use among this patient population. After a year, the TPS program was expanded to include other surgical patient populations. To support implementation, electronic decision support tools were created, including electronic medical record order sets to standardize practice, and decision-support dashboards to facilitate case review at the patient-level by all members of the TPS team.

Study Design

We used a pre-post study design to compare changes in postoperative opioid use among patients undergoing orthopedic surgery procedures before and after implementation of the TPS intervention. Patients in the pre-TPS group who had primary or revision total knee, hip, or shoulder surgery or rotator cuff surgery at the Salt Lake City VAMC between January and December 2017 were compared to patients undergoing the same surgical procedures who were enrolled in TPS during 2018. Veterans who had a second surgery or that passed away within 90 days after their joint surgery were excluded from this analysis. This study was approved by the University of Utah Institutional Review Board and VA Research Review Committee, and informed consent was waived.

TPS and pre-TPS Groups

For the pre-TPS group, medical records and state-controlled substance databases were reviewed to ascertain baseline demographics, history of substance use disorder, depression, anxiety, PTSD or other mental health diagnosis, and use of opioid medications before and after surgery. MEDD was calculated at baseline prior to surgery and at 90 days after discharge based off of active prescriptions in the medical record and/or state-controlled substance database at those time points. Number of opioid tablets prescribed at discharge was recorded. Patients were designated as chronic opioid users if they had received a prescription of opioids for either 60 continuous days prior to surgery, or if they filled 3 or more prescriptions for opioids within 180 days prior to surgery. Veterans who did not meet these criteria were considered opioid naïve. New chronic opioid use after surgery was defined as having either an active opioid prescription at 90 days post discharge or filling an opioid prescription between 90-120 days after discharge.

Patients in the TPS cohort had opioid use history and MEDD documented in TPS clinic notes using patient report as well as medical record and controlled substance database verification prior to surgery and at 90 days after discharge. Number of opioid tablets prescribed at discharge was recorded. In addition, history of mental health disorders and substance abuse history were recorded at baseline prior to surgery.

Outcome measures

The primary outcome measure for this study was the proportion of patients taking any opioid medication at 90-days after surgery. Secondary outcomes included the proportion of chronic opioid use (COU) patients who were either weaned off opioids or decreased their opioid dose as compared to pre-operative levels, the proportion of non-opioid users (NOU) patients still on opioids after 90 days, and the number of opioid tablets prescribed at discharge.

Statistical Analysis

Baseline patient characteristics were summarized stratified by the pre-TPS and post-TPS exposure groups. Continuous variables were summarized as mean, standard deviation (SD), median, interquartile range (IQR), and range; and analyzed using a t-test for approximately normally distributed variables and a Wilcoxon sum test otherwise. Categorical variables were summarized as count (%) and analyzed using a chi-squared test. A Cochran-Armitage trend test was used to compare 90-day outcomes coded as an ordinal variable (off opioids, reduced, same, increased) among the pre- and post-TPS patients that had COU. We also used a chi-squared test to compare off or reduced vs. same or increased opioid use. We first compared predictor variables between the pre-TPS and post-TPS NOU and COU groups using univariate analysis. A multivariable logistic regression model was then used to assess the relationship between TPS exposure status and post-operative COU, adjusting for age, type of procedure, number of days in hospital, and COU at baseline. Covariates were selected for adjustment in logistic regression models if they met statistical significance at the p < 0.1 level in univariate analyses. Odds ratios (ORs) were reported with 95% confidence intervals (CI) and p values. Statistical significance was assessed at the 0.05 level, and all tests were two-sided. Pre and post implemention outcomes for number of opioid tablets prescribed at discharge and percentage of new chronic opioid use are presented in a Statistical Process Control Chart¹⁹. All analyses were conducted using R v.3.6.1 (R Foundation for Statistical Computing, Vienna, Austria).

Results

A total of 164 patients met criteria for the TPS program between January and December 2018, and were compared to 172 pre-TPS patients from the year prior that underwent the same types of orthopedic procedures. This cohort included 53 (31%) pre-TPS patients and 37 (23%) patients in the TPS cohort with a history of chronic opioid use before surgery. The characteristics of patients in pre-TPS and TPS groups prior to surgery are shown in Table 1.

Table 1.

Characteristics of patients enrolled in the Transitional Pain Service (TPS) and No TPS patients undergoing the same major joint procedures during the year prior.

Variable	No TPS N=172	TPS N=164	P-value
Age, mean (SD)	65.7 (9.9)	64.2 (12.0)	0.21
Male Sex, n (%)	159 (92.4)	145 (88.4)	0.21
BMI, median (IQR)	31.0 (28-35)	31.6 (29-35)	0.39
Hx of Mental Health Disorders, n (%)	81 (47.1)	79 (48.2)	0.84
Hx of Substance Use Disorders, n (%)	25 (14.5)	22 (13.4)	0.77
Surgical Procedure, n (%)			0.38
Rotator Cuff Repair	40 (23.3)	33 (20.1)
Total Hip Arthroplasty	46 (26.7)	34 (20.7)
Total Knee Arthroplasty	66 (38.4)	72 (43.9)
Total Shoulder Arthroplasty	20 (11.6)	25 (15.2)
Hospital length of stay, median (IQR)	2.0 (1-2)	2.0 (1-2)	0.58
Opioid Use History
Chronic opioid use, n (%)	53 (30.8)	37 (22.6)	0.09
Preop MEDD, mean (SD)	15.4 (35.8)	10.3 (31.2)	0.07

Abbreviations: SD: standard deviation; BMI: body mass index; IQR: interquartile range; MEDD: Morphine equivalent daily dose; TPS: transitional pain service

After implementation of TPS there was a significant reduction in the number of opioid tablets prescribed to patients at the time of hospital discharge (TPS: 45 (25,60) vs pre-TPS: 80 (60,90); P<0.001) (Figure 1). Opioid tablets prescribed by month is shown in Figure 2. This finding was consistent for patients who were opioid naïve as well as on chronic opioid therapy before surgery.

Figure 1.

Number of opioid tablets prescribed at hospital discharge before and after implementation of a transitional pain service (TPS).

Figure 2.

Statistical Control Chart for number of opioid tablets prescribed at hospital discharge, by month, before and after implementation of a transitional pain service (TPS). Dots are average number of tabs prescribed at discharge per month. Solid horizontal line is the mean number of tabs prescribed at discharge in 2017. Two dashed horizontal lines represent 3 standard deviations from the mean of the monthy number of tabs at discharge for year 2017. In 2018, all months had an average #tabs at discharge below the central line (2017 average), 3 months (7, 9, and 12) were outside of the lower boundary (mean −3SD), suggesting special causes of variation.

The decrease in opioid use associated with the TPS intervention was found to extend beyond three months after surgery for patients who were either opioid naïve or on chronic opioids before surgery. Only 22 (13.4%) TPS patients were still on opioids after 90-days as compared to 47 (27.3%) pre-TPS patients (p=0.002). Among individuals who were opioid naïve prior to surgery, only a single patient who received the TPS intervention continued opioids beyond 90 days after hospital discharge (0.7% vs. 8.4%; P=0.004) as compared to 10 patients from the pre-TPS period. Figure 3 shows this trend over time. Similarly, the TPS intervention was effective for patients on chronic opioids before surgery. As shown in Table 2, among chronic opioid users there was a significant increase in the proportion of patients enrolled in the TPS program who either completely stopped their opioids or decreased their preoperative opioid dose (67.5% vs. 45.3%) when compared to pre-TPS (P=0.037).

Figure 3.

Statistical Control Chart for proportion of opioid naïve veterans with new persistent opioid use before and after implementation of a transitional pain service (TPS). Dots are % new chronic opioid use (COU) in each quarter. Solid horizontal line is the mean new COU% in 2017. Two dashed horizontal lines are 3 standard deviations from the mean new COU% in 2017. In 2018, new COU% in all 4 quarters were below the central line, Quarters 2~4 had new COU% outside of the lower boundary (mean −3SD), suggesting special causes of variation.

Table 2.

90-day outcomes among patients with history of chronic opioid use who received the Transitional Pain Service (TPS) intervention as compared to standard care during prior year (No TPS).

Outcome	No TPS N=53	TPS N=37	P-value
Off or Reduced Opioid Use, n (%)	24 (45.3)	25 (67.5)	0.037a
Off all opioids, n (%)	16 (30.2)	16 (43.2)
Reduced opioid use, n (%)	8 (15.1)	9 (24.3)
Same or Increased Opioid Use, n (%)	29 (54.7)	12 (32.5)
Same opioid dose as baseline, n (%)	21 (39.6)	10 (27)
Increased opioid use, n (%)	8 (15.1)	2 (5.5)

^aChi-square test comparing Off or Reduced vs Same or Increased

As a result, fewer chronic opioid users engaged by TPS were found to have increased their opioid dose at 90-days (5.5%-TPS vs. 15.1%-Pre-TPS) following surgery. However, the trend across these ordered levels was not statistically significant (P=0.054).

Multivariable logistic regression analysis showed 69% lower odds of post-operative chronic opioid use in the TPS group compared to the pre-TPS group (OR:0.31; 95%CI: 0.14 ~ 0.66, p=0.03, Table 3).

Table 3.

Multivariable regression analysis to assess independent factors associated with chronic opioid use following orthopedic joint surgery

Variable	Odds Ratio (95% Confidence Interval)	P-value
Post-TPS vs. Pre-TPS	0.32 (0.14 – 0.69)	0.005
Age at Discharge	1.01 (0.97 – 1.05)	0.61
Type of Surgery
Hip Arthroplasty	0.86 (0.24 – 3.16)	0.82
Total Knee Arthroplasty	1.74 (0.58 – 5.77)	0.34
Total Shoulder Arthroplasty	2.25 (0.59 – 8.78)	0.24
Length of Hospital Stay	1.08 (0.82 – 1.34)	0.52
Pre-op MEDD >0	1.08 (1.06 – 1.11)	<0.001

Abbreviations: TPS: Transitional Pain Service; MEDD: Morphine milligram equivalent daily dose

Chronic opioid use at baseline was associated with over 40 times higher odds of postop chronic opioid use (OR=43.2, 95% CI: 20.1~102.1, p<0.001). In this model, patient age, type of procedure, and hospital days were not independently associated with chronic opioid use after surgery adjusting for TPS intervention and baseline chronic opioid use.

Discussion

Perioperative care coordination for pain management is commonly fragmented and increases the risk for chronic opioid use after surgery. Implementing a TPS has been suggested as one approach to address this issue and to optimize the perioperative pain management strategy^20–22. Here we describe the successful implementation of a TPS in a VA medical center that utilizes a multidisciplinary and multimodal approach across preoperative, surgical hospitalization, and postoperative transitions of care to address the problem of fragmented care coordination. Our data shows that when patients receive preoperative education and are followed closely for at least 6 months after surgery, overall post-operative opioid use can be significantly reduced for both previously opioid naïve as well as chronic opioid users. It’s noteworthy that among opioid naïve patients in this study, TPS achieved substantial reduction of new chronic opioid use after surgery. In addition, the majority of patients with prior chronic opioid use were able to transition completely off opioids within 90 days after surgery or experience a reduction in their opioid dose. Together, these findings support the role for a TPS in optimizing perioperative pain management and reducing chronic opioid use among at risk patients.

Numerous evidence-based strategies have been promoted and/or put into practice during the preoperative, intraoperative and postoperative period as a means to reduce opioid use and prevent CPSP. This includes individually tailored programs for preoperative education or pain management planning^23–25; use of multimodal analgesia including regional or neuraxial techniques or non-opioid systemic medications²⁵; use of non-pharmacologic modalities such as cognitive based intervention²⁶; as well as coordinated approach to post-discharge instructions and transitions of care²⁶. Each of these individual strategies by themselves has been shown to have some effect on improving postoperative pain management. And all of these measures are supported by current professional guidelines for the management of postoperative pain²⁷.

There has been limited data, however, to show the beneficial effect when these therapeutic modalities are all bundled together into a single perioperative intervention. A multidisciplinary TPS program provides the mechanism within a health system for delivering multiple interventions to patients at high risk for CPSP^14,20. Our study demonstrates the effectiveness of a TPS that integrates preoperative education and individual pain management planning in addition to post-operative care. This is a central component of our approach based on collective evidence showing that managing patient expectations before surgery reduces patient anxiety, perioperative opioid consumption, and hospital length of stay^28–30.

The other main function of a TPS is to ensure that this personalized pain management plan is carried out across all transitions of care. A TPS coordinates care across all transitions in the inpatient and outpatient setting and effectively lowers the risk that patient information is miscommunicated among surgical and non-surgical providers²¹. This type of service is well-suited to an integrated health care system such as the VA given the shared electronic medical record system, the ability to collect and track data in both inpatient and outpatient settings, and the relative ease of communication among surgeons, primary care, and mental health providers. Moreover, coordination of care is facilitated given that most veterans who have surgery at a VA hospital typically receive all of their care through the VA healthcare system. In fact, the electronic note templates we created were designed to be utilized at other VA hospitals during future TPS dissemination, allowing common data elements to be captured and helping to guide best practices for perioperative pain management. Further, the real-time capturing of data through patient care notes allowed us to develop a provider-facing clinical decision tool that facilitated regular follow-up at specified intervals and ease of visualizing pertinent patient information in a single place.

Given the resource intensive nature of a TPS like ours, we recognize that there is a need to demonstrate scalability and cost-effectiveness. After the first year of implementation of our TPS (2018), we expanded to include Veterans having all types of surgery and have enrolled >1000 additional Veterans since that time. We are also currently performing a cost analysis study. Additional work is needed to evaluate if a model such as this would be successful and feasible at other institutions with different financial models and higher surgical volume.

Our study has several limitations to discuss. First, we used a pre-post study design that may have been confounded by temporal changes in opioid prescribing patterns and as well as regression to the mean. Second, data between time periods was not collected in the same manner. While data was collected prospectively among patients enrolled in the TPS cohort, we had to perform retrospective electronic chart abstraction among patients in the historic pre-TPS group. As such, some degree of ascertainment bias may have been introduced. Third, there may be some unmeasured confounders in our analysis that influence risk of chronic opioid use between patients enrolled in the TPS and the historic pre-TPS group and contribute to treatment selection bias. Finally, the reduction in chronic opioid use observed among patients in the TPS program may have been influenced by other VA initiatives designed to reduce opioid use implemented during the study time period.

Conclusions

The significant reduction in chronic opioid use observed in this pilot study of orthopedic surgery patients underscores the potential for a multidisciplinary TPS approach to comprehensive perioperative pain management. Future directions include evaluating TPS among other surgical patient populations as well as exploring implementation of the service for veterans who receive care through the VA but choose to have surgery outside of the VA medical system. In addition, it will be important to identify those who are at risk for prolonged opioid use and poor functional outcomes to better focus resources on those who would most benefit from a TPS.

Abbreviations:

TPS

transitional pain service

VA

Veterans Affairs

CPSP

chronic post-surgical pain

PROMIS

patient reported outcomes measurement information system

PCS

pain catastrophizing scale

MBI

mindfulness based intervention

ACT

acceptance and commitment therapy

ERAS

enhanced recovery after surgery

NSAID

non-steroidal anti-inflammatory drug

LIA

local infiltrative anesthesia

MEDD

morphine equivalent daily dose

COU

chronic opioid user

NOU

non-opioid user

SD

standard deviation

IQR

interquartile range

CI

confidence interval