BACKGROUND: Chronic low back pain (CLBP) is the leading cause of disability in the United States. People suffering from CLBP often have multiple comorbidities including depression, anxiety, and substance use disorder (SUD). Although the opioid epidemic has intensified the search for new treatment options, both pharmacological and other, opioids still remain the most common treatment for chronic pain. Long-term opioid therapy (LTOT) has been shown to lead to opioid-induced hyperalgesia (OIH), an increased sensitivity to painful stimuli. It remains unclear, however, the extent to which reductions in opioid dose impact OIH. METHODS: This is a longitudinal cohort study whose primary aim is to determine how changes in opioid doses are associated with changes in psychosocial and quantitative sensory testing (QST) variables. Participants were 24 adults with CLBP being treated with LTOT and visits were conducted on a monthly basis for six months. All 24 participants were included in the analysis of demographic and psychosocial variables (disability, anxiety, depression, opioid misuse, pain severity, pain interference, and catastrophizing). A subset of 13 participants were included in the analysis of QST variables. RESULTS: We found that pressure pain thresholds at the thumb and the trapezius, and heat pain threshold significantly (p < 0.05) improved between visit 1 and visit 6. We also found that a decrease in morphine equivalent doses (MED) is correlated (coefficient > 0.2) with improvements in punctuate probe rating, pain pressure at the thumb, and maximum cold ratings. DISCUSSION: Our results show that reductions in opioid dose are associated with reduced pain sensitivity, even while the psychosocial variables studied (including subjective pain score, depression, and anxiety) remain stable.

<p>  </p> <p><strong>Background:</strong> Older adults have a higher prevalence of pain compared to other age groups and are more likely to become long-term opioid users. The clinical benefits of long-term opioid therapy (LTOT) are not clearly known, however, LTOT has been found to increase the risk of all-cause mortality, opioid overdose, constipation, fractures, and myocardial infarction. </p> <p><br></p> <p><strong>Objective: </strong>The study was conducted to estimate the incidence of LTOT and risk factors associated with LTOT in older adults aged 65 years and older.</p> <p><br></p> <p><strong>Methods:</strong> This was a retrospective cohort study based on Medicare claims data obtained from Research Data Assistance Center (ResDAC). Opioid naïve older adults filling an opioid prescription between 2014 and 2016 were included. The outcome was LTOT which was defined as an opioid use episode lasting longer than 90 days and having more than 60 cumulative days of supply. The independent variables (risk factors) were patient characteristics (demographics, comorbidities, substance use disorders), characteristics of initial/index opioid dispensed (opioid type, duration of action of opioid, opioid dose, number of days’ supply, concomitant medications), and pain conditions. Multivariable logistic regression was performed to assess the association between the risk factors and LTOT. To address statistical interactions among variables, secondary analyses were conducted after stratifying the dataset by pain conditions.</p> <p><br></p> <p><strong>Results:</strong> Among 162,287 opioid naive patients, 10,296 (6.3%) transitioned to LTOT. Demographic characteristics associated with LTOT were age greater than 85 years (adjusted odds ratios [AOR]: 1.1, 95% confidence interval [CI]:1.03-1.18) and being black (AOR: 1.11, 95% CI: 1.01-1.22). Risk factors related to substance use disorders included drug use disorder (AOR: 1.59, 95% CI: 1.30-1.95), alcohol use disorder (AOR: 1.26, 95% CI: 1.06-1.49), tobacco use disorder (AOR: 1.33, 95% CI: 1.21-1.45), and a history of opioid use disorder (OUD) (AOR: 1.63, 95% CI: 1.34-1.98). Patients with more than 5 comorbidities had 1.56 times higher odds (95% CI: 1.46-1.66) of LTOT compared to patients with 0-2 comorbidities. Characteristics of initial/index opioid associated with LTOT were dispensing long-acting opioids (AOR: 1.73, 95% CI: 1.22-2.46), concomitant use of benzodiazepines (AOR: 1.19, 95% CI: 1.11-1.28), gabapentinoids (AOR: 1.59, 95% CI: 1.49-1.69), and non-steroidal anti-inflammatory drugs (NSAIDs) (AOR: 1.23, 95% CI: 1.16-1.30). Starting therapy with tramadol increased the odds of LTOT compared to hydrocodone in patients with osteoarthritis and joint pain (AOR: 1.22, 95% CI: 1.06-1.41) as well as abdominal and bowel pain (AOR: 1.53, 95% CI: 1.05- 2.22). However, starting therapy with oxycodone decreased the odds of LTOT in patients with osteoarthritis and joint pain (AOR: 0.69, 95% CI: 0.53-0.90). For all pain conditions, initial opioid supply of ≥30 days led to 10-16 times higher odds of LTOT compared to days’ supply of 1-3 days.</p> <p><br></p> <p><strong>Conclusions:</strong> Higher age, black race, comorbidities, substance use disorders, and history of OUD are the patient-related risk factors of LTOT in older adults. Moreover, specific patterns of initial/index opioid prescription/dispensing such as greater number of days’ supply, dispensing long-acting opioids, and concomitant use of benzodiazepines, gabapentinoids, and NSAIDs increase the odds of LTOT. Prescribers should take these factors into consideration when prescribing opioids to older adults.</p>