Quantitative Sensory Testing in Chronic Pain Patients Undergoing Opioid Treatment and Opioid Tapering

Study Overview
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Brief Summary
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Few studies have used quantitative sensory tests to study the effect of chronic opioid treatment on sensation. The investigators will test chronic pain patients who are on different MEDDs, normal volunteers, and patients undergoing an opioid taper. This will be the first study to perform sensory testing on patients while undergoing an opioid taper on an outpatient basis.

Detailed Description
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Death from drug overdoses reached a record high in 2014, with the majority involving an opioid. The United States government has labeled this an epidemic due to the progressive rise in opioid-involved deaths. In 2015, the Centers for Disease Control and Prevention determined that, on average, 650,000 opioid prescriptions are dispensed daily in the United States alone. It is well-documented and observed in clinical practice that patients on chronic opioid therapy will commonly require an escalation in opioid dose over time to maintain analgesia. The consequence of such escalations is the development of tolerance to opioids, along with other known adverse effects of opioids including respiratory depression, constipation, and potential for addiction. The drastic increase in opioid doses over the years has urged the CDC to release a report for primary care clinicians treating patients with chronic pain. This report provides a risk assessment and recommendations for prescribing opioids for non-cancer chronic pain. The guidelines state that careful reassessment of individual benefits must be considered when increasing doses to ≥50 morphine milligram equivalents (MME)/day, and that increases to ≥90 MME/day must be avoided, with recommendations for consultation with a specialist. Avoiding high opioid doses will also minimize the development of opioid-induced hyperalgesia, which is a paradoxical response to increases in opioid doses; these patients become increasingly sensitized to painful stimuli. While the precise mechanism of this condition remains to be elucidated, treatment includes reducing and tapering opioids. Interestingly, an article on patient-reported outcomes surveyed a group of 517 patients that revealed the higher opioid dose group to have greater pain intensity, poorer self-efficacy for managing pain, and more impairment in functioning and quality of life. Several studies have looked at the use of various pain testing models to investigate the effects of chronic opioid therapy and changes in pain perception. A systematic review of the literature was performed to identify clinical studies incorporating measures of hyperalgesia in patients on chronic opioid therapy. This review was aimed at finding the optimal testing modality to evaluate pain threshold and tolerance to external stimuli, including mechanical (pressure, touch, injection), thermal (cold/heat), and electrical. Although the results did not reveal any one method with sufficient power, several prospective studies evaluating hyperalgesia with heat pain ratings have shown some promising results; two studies revealing significant changes in heat responses for opioid treatment groups, and one study demonstrating lower heat pain perception values following an opioid taper. The latter study is unique in that research pertaining to changes in pain sensitivity on patients following an opioid taper is lacking. Little is known at this juncture how pain thresholds change to opioid dose reductions and following completion of a taper. The purpose of the study is to objectively measure pain threshold levels in patients without opioids, low dose opioids, high dose opioids and patients undergoing a taper from long-term opioid therapy. This study utilizes taper techniques that are commonly employed in a pain medicine practice. The innovation involves use of quantitative measures of sensitivity to evaluate patients on differing opioid doses and undergoing current taper practices.

Official Title
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Quantitative Sensory Testing in Chronic Pain Patients Undergoing Opioid Treatment and Opioid Tapering

Conditions
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Analgesic Drug Dependence, Sensory Deficit

Intervention / Treatment
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* Behavioral: sensory testing (Heat, cold, and pressure)
* Behavioral: Promis Survey


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient age between 18 and 75 History of chronic pain for at least 3 months Patients may have been selected for opioid taper by their pain physicians. Patients may or may not be on opioid therapy. They must have the ability to understand the protocol and provide voluntary, written, informed consent. Exclusion Criteria: Cancer pain Unstable medical conditions (including but not limited to history of myocardial infarction within the past year, autoimmune diseases, uncontrolled diabetes with hemoglobin A1C of greater than 10) Pregnancy Inability to adequately answer surveys History of substance abuse within 5 years Surgery within the past month Surgery planned during the next six months Use of systemic steroids.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: taper<br>participants undergoing a taper as directed by their pain physician. Interventions include sensory testing ( heat, cold, and pressure) and PROMIS surveys. | Behavioral: sensory testing (Heat, cold, and pressure)<br>* sensory threshold measurement is the point at which the participant feels pain due to either heat, cold, or pressure<br>Behavioral: Promis Survey<br>* PROMIS computer adaptive survey in anxiety, depression, pain behavior, fatigue, pian interference, physical function, sleep disturbance, self efficacy<br>|
| Placebo Comparator: non taper systemic <90<br>participants on systemic opioids < 90 MEDD (morphine equivalent daily dose) and no taper | Behavioral: sensory testing (Heat, cold, and pressure)<br>* sensory threshold measurement is the point at which the participant feels pain due to either heat, cold, or pressure<br>Behavioral: Promis Survey<br>* PROMIS computer adaptive survey in anxiety, depression, pain behavior, fatigue, pian interference, physical function, sleep disturbance, self efficacy<br>|
| Placebo Comparator: non taper systemic >90<br>participants on systemic opioids > 90 MEDD and no taper | Behavioral: sensory testing (Heat, cold, and pressure)<br>* sensory threshold measurement is the point at which the participant feels pain due to either heat, cold, or pressure<br>Behavioral: Promis Survey<br>* PROMIS computer adaptive survey in anxiety, depression, pain behavior, fatigue, pian interference, physical function, sleep disturbance, self efficacy<br>|
| Placebo Comparator: non taper intrathecal<br>Participants on intrathecal therapy and no taper | Behavioral: sensory testing (Heat, cold, and pressure)<br>* sensory threshold measurement is the point at which the participant feels pain due to either heat, cold, or pressure<br>Behavioral: Promis Survey<br>* PROMIS computer adaptive survey in anxiety, depression, pain behavior, fatigue, pian interference, physical function, sleep disturbance, self efficacy<br>|
| Sham Comparator: non opioids<br>Participants on non-opioid therapy will undergo behavioral tests and PROMIS surveys | Behavioral: sensory testing (Heat, cold, and pressure)<br>* sensory threshold measurement is the point at which the participant feels pain due to either heat, cold, or pressure<br>Behavioral: Promis Survey<br>* PROMIS computer adaptive survey in anxiety, depression, pain behavior, fatigue, pian interference, physical function, sleep disturbance, self efficacy<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heat threshold measurements | Heat threshold measurements (degrees Celsius) will be obtained using a pen-shaped temperature probe. Tests will be performed on a designated painful and non-painful body surface. Testing will completed when patient reports numeric pain rating of 5 or greater, or at a temperature >49 degrees Celsius. | 2 years | 
| Cold threshold measurements | Cold threshold measurements (degrees Celsius) will be obtained using a pen-shaped temperature probe. Tests will be performed on a designated painful and non-painful body surface. Testing will be completed when patient reports discomfort with cold stimulus, or if probe temperature reaches 0 degrees Celsius. | 2 years | 
| Pressure threshold measurements | Pressure threshold measurements (Newtons) will be obtained using a hand-held algometer. Tests will be performed on a designated painful and non-painful body surface. Testing will be completed when patient reports discomfort with pressure stimulus, or if pressure exceeds 60 Newtons. | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PROMIS surveys | PROMIS (Patient-Reported Outcomes Measurement Information System) surveys will be administered at the subject's initial, halfway and end of their evaluations. These measures include topics on anxiety, depression, pain behavior, fatigue, pain interference, physical function, sleep disturbance. The results from the surveys will be aggregated and compared to other participants' responses. | 2 years |