Pain
-
There is a great deal of concern about opioid use in veterans, particularly those who served in Afghanistan (OEF) and Iraq (OIF and OND). The current study provides a detailed pharmacoepidemiologic analysis of opioid use among OEF/OIF/OND veterans from FY09 to FY12. Data from 3 data repositories from the Veterans Health Administration (VHA) were used to describe demographic, clinical, and medication characteristics associated with opioid use among OEF/OIF/OND veterans and among those with TBI. ⋯ Back pain was also strongly associated with chronic use (OR = 2.50, P < 0.0001). As pain severity increased the odds of chronic opioid use also increased: mild pain (OR = 3.76, P < 0.0001), moderate pain (OR = 6.80, P < 0.0001), and severe pain (OR = 8.49, P < 0.0001). Opioid use among OEF/OIF/OND veterans is characterized by moderate doses that are used over relatively long periods of time by a minority of veterans.
-
Review Meta Analysis
Polysubstance use and misuse or abuse of prescription opioid analgesics: A multi-level analysis of international data.
Increasing mortality and morbidity associated with opioid analgesics has led to concerns about their misuse and abuse, even when obtained through a prescription. These concerns have been most pronounced in the United States, but limited data make it difficult to determine whether it is a problem in other countries. We investigated opioid analgesic misuse and abuse in participants from the Global Drug Survey 2015 resident in the United States (N = 1334), United Kingdom (N = 1199), France (N = 1258), Germany (N = 866), and Australia (N = 1013) who had used at least 1 prescription opioid analgesic medication in the past year. ⋯ In multilevel models, country of residence accounted for less than 3% of the variance in opioid analgesic misuse or abuse. Adjusting for country of residence and sociodemographic factors, use of illicit drugs and benzodiazepines was associated with 4-fold greater odds of misuse (odds ratio 4.36, 95% confidence interval 3.29-5.93) and 6-fold greater odds of abuse compared with not using either drug (odds ratio 6.49, 95% confidence interval 4.0-10.48), although the strength of the association with abuse varied by country. Misuse and abuse by those prescribed opioid analgesics seem to be a problem that is not limited to the United States and warrant attention on an international scale.
-
Randomized Controlled Trial
Side effects can enhance treatment response through expectancy effects: an experimental analgesic randomized controlled trial.
In randomized controlled trials, medication side effects may lead to beliefs that one is receiving the active intervention and enhance active treatment responses, thereby increasing drug-placebo differences. We tested these hypotheses with an experimental double-blind randomized controlled trial of a nonsteroidal anti-inflammatory drug with and without the addition of atropine to induce side effects. One hundred healthy volunteers were told they would be randomized to either combined analgesics that might produce dry mouth or inert placebos. ⋯ A chain of mediation analysis demonstrated that the addition of atropine increased dry mouth symptoms, which increased beliefs that one had received the active medication, which, in turn, increased analgesia. In addition to this indirect effect of atropine on analgesia (via dry mouth and beliefs), analyses suggest that among those who received diclofenac, atropine directly increased analgesia. This possible synergistic effect between diclofenac and atropine might warrant future research.
-
Multicenter Study
Prevalence and incidence of chronic pain with or without neuropathic characteristics in patients with cancer.
This prospective national multicenter study was carried out to estimate the prevalence and incidence of chronic pain with or without neuropathic characteristics in patients with cancer in France. All consecutive outpatients (n = 1885) seen over 2 weeks for cancer treatment in 12 oncology units were invited to participate in the study, and 1805 were included. Patients underwent a clinical examination during visit 1, and a questionnaire was completed to detect chronic pain (defined as daily pain for at least 3 months), and to characterize its intensity, location, and neuropathic characteristics (ie, DN4 score ≥4). ⋯ Pain intensity and interference were higher in patients with neuropathic characteristics. In total, 1285 patients were included in the incidence study, 873 of whom were seen at least once, 3, or 6 months after the first visit. The incidence of chronic pain during the 6-month follow-up period ranged from 13% to 28%, depending on primary tumor location, and neuropathic characteristics were found in 19.9% of patients with chronic pain.
-
Chronic pain symptoms often change over time, even in individuals who have had symptoms for years. Studying biological factors that predict trends in symptom change in chronic pain may uncover novel pathophysiological mechanisms and potential therapeutic targets. In this study, we investigated whether brain functional connectivity measures obtained from resting-state functional magnetic resonance imaging at baseline can predict longitudinal symptom change (3, 6, and 12 months after scan) in urologic chronic pelvic pain syndrome. ⋯ In addition, we found that the brain regions with greatest contribution to the classification were preferentially aligned with the left frontoparietal network. Resting-state functional magnetic resonance imaging measures seemed to be less informative about 6- or 12-month symptom change. Our study provides the first evidence that future trends in symptom change in patients in a state of chronic pain may be linked to functional connectivity within specific brain networks.