Quantitative Sensory Testing in Chronic Pain Patients Undergoing Opioid Treatment and Opioid Tapering
Condition: Analgesic Drug Dependence; Sensory Deficit
MeSH terms: Chronic Pain; Substance-Related Disorders
Study type: Interventional

Summary: 
      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: 
      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.
    

Intervention name(s): sensory testing (Heat, cold, and pressure); Promis Survey
Intervention type(s): Behavioral; Behavioral
Intervention description(s): sensory threshold measurement is the point at which the participant feels pain due to either heat, cold, or pressure; PROMIS computer adaptive survey in anxiety, depression, pain behavior, fatigue, pian interference, physical function, sleep disturbance, self efficacy
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic