Elevated Pain Sensitivity in Chronic Pain Patients at Risk for Opioid Misuse

Abstract

This study employed quantitative sensory testing (QST) to evaluate pain responses in chronic spinal pain patients at low risk and high risk for opioid misuse, with risk classification based on scores on the Screener and Opioid Assessment for Patients with Pain-Revised (SOAPP-R). Patients were further sub-grouped according to current use of prescription opioids. Of the 276 chronic pain patients tested, approximately 65% were taking opioids; a median split was used to further categorize these patients as being on lower or higher doses of opioids. The highrisk group (n= 161) reported higher levels of clinical pain, had lower pressure and thermal pain thresholds at multiple body sites, had lower heat pain tolerance, and rated repetitive mechanical stimuli as more painful relative to the low-risk group (n= 115; p’s< .01). In contrast, QST measures did not differ across opioid groups. Multiple linear regression analysis suggested that indices of pain-related distress (i.e., anxiety and catastrophizing about pain) were also predictive of hyperalgesia, particularly in patients taking opioids. Collectively, regardless of opioid status, the high-risk group was hyperalgesic relative to the low-risk group; future opioid treatment studies may benefit from the classification of opioid risk, and the examination of pain sensitivity and other factors that differentiate high- and low-risk groups.

Changes in Pain Sensitivity and Pain Modulation During Oral Opioid Treatment: The Impact of Negative Affect

“…QST has been recommended as both a phenotyping and outcome measure in clinical trials of analgesics [26,41], and we have used these standardized psychophysical tests in a number of prior studies [23,42,43].…”

“…Mechanical force was applied using a 0.5 cm 2 probe covered with polypropylene pressure-transducing material; pressure was increased at a steady rate of 30 kPA/s until the subject indicated that the pressure was "first perceived as painful." Subjects then underwent an assessment of mechanical temporal summation using weighted pinprick stimulators, as in previous studies [23]. The lowest-force stimulator that produced a sensation of discomfort (128 or 256 mN for most subjects) was used to apply a train of 10 stimuli to the skin on the dorsum of the hand at the rate of 1 per second.…”

“…Such findings suggest that opioid-induced maladaptive sensory changes might be restricted to subgroups of patients, which could conceal OIH effects when analyzing grouplevel effects. For example, important biopsychosocial factors such as pain-related catastrophizing and negative affect (NA) are known to shape individual differences in a variety of pain responses, and some recent data from our lab suggests that they may systematically place patients at elevated risk for the development of OIH [23]. Interestingly, patients scoring very high on measures of psychological distress tend to be systematically excluded from RCTs, even though this subgroup of patients is highly prevalent within the chronic pain population [24,31,43].…”

Evaluation of How Depression and Anxiety Mediate the Relationship between Pain Catastrophizing and Prescription Opioid Misuse in a Chronic Pain Population

“…Studies have found that young age, a history of substance abuse [7,8], higher levels of pain [9], and increased pain sensitivity [10] act as predictors in the development of prescription opioid misuse and addiction. Research has also shown that psychological constructs, such as cognitive styles and negative affect, play a crucial role in the development of opioid misuse and abuse.…”

“…It has long been observed that, among chronic pain patients, those who score higher on catastrophizing scales tend to be at a much higher risk for prescription opioid misuse [9,10,13] These patients are unable to generate effective thoughts about how to deal with constant pain and often report helplessness and increased levels of pain severity [14], pain sensitivity [15], and negative affect [10].…”