Human Studies

To examine the change in the Patient Activation Measure and physical and psychosocial outcome measures in a military interdisciplinary intensive outpatient program for persistent pain. Pre- and post-intervention measures, which were also stratified by gender and baseline activation, included patient-reported outcomes and physical function assessment, obtained from 2017 to 2018 program database. The majority of the participants were male (70.9%), with an average age of 29.18 years and pain duration of 4.78 years (n = 103). Patient activation, majority of the patient reported outcomes and functional assessments improved in the overall sample with fewer changes in females on the Defense and Veterans Pain Rating Scale. Improvements were noted on the Patient Activation Measure and majority of the other outcome measures suggesting that service members with persistent pain at any level of patient activation or baseline function, may benefit from an intensive outpatient program.

Previous studies have found a negative association between a conditioning pain modulating (CPM) response and pain catastrophizing among pain-free subjects. This study investigated the difference in CPM response between patients with chronic low back pain (CLBP) and healthy controls, and the association between pain catastrophizing and the CPM response.

Chronic pain (CP) was associated with impaired cognitive performance in several cross-sectional studies conducted in older adults; however, fewer longitudinal studies assessed this link which remains still debated. With a prospective design, the present analysis was aimed at evaluating the relationship between CP and the change in several tests assessing memory, attention, verbal fluency and processing speed. The study population was selected from the PAQUID study, a cohort of community dwellers aged 65 and over; 693 subjects receiving a pain assessment were included. CP was evaluated using a questionnaire administered at 3-year follow-up. Cognitive performances were assessed every 2-3 years between 3 and 15 years assessing general cognition (MMSE), verbal and visual memory (word paired associate test and Benton test) attention and speed processing (Wechsler DSST, Zazzo's cancellation task) language skills and executive functions (Isaacs set test). The link between CP and the change in cognitive function was assessed with latent process mixed models controlled for age, gender, education, comorbidities, depression and analgesic drugs. The association between CP and each of the cognitive scores was then tested with the same procedure. A significant relationship was observed between CP and poorer 15-year scores on global cognitive performance (p=0.004), and specifically DSST (p=0.002) associated with a higher slope of decline (p=0.02). CP is associated with higher cognitive decline, in particular in processing speed. This result reinforces the importance of actively treating CP with pharmacological and non-pharmacological strategies to prevent its consequences, including cognitive consequences.

Sex-related differences can influence outcomes of randomized clinical trials and may jeopardize the effectiveness of pain management and other therapeutics. Thus, it is essential to understand the mechanistic and translational aspects of sex differences in placebo outcomes. Recently, studies in healthy participants have shed light on how sex-related placebo effects might influence outcomes, yet no research has been conducted in a patient population. Herein, we used a tripartite approach to evaluate the interaction of prior therapeutic experience (e.g. conditioning), expectations, and placebo effects in 280 chronic (orofacial) pain patients (215 women). In this cross-sectional study, we assessed sex differences in placebo effects, conditioning as a proxy of prior therapeutic effects, and expectations evaluated before and after the exposure to positive outcomes, taking into account participant-experiment sex concordance and hormonal levels (estradiol and progesterone assessed in premenopausal women). We used mediation analysis to determine how conditioning strength and expectations impacted sex differences in placebo outcomes. Independent of gonadal hormone levels, women showed stronger placebo effects than men. We also found significant statistical sex differences in the conditioning strength and reinforced expectations whereby reinforced expectations mediated the sex-related placebo effects. Additionally, the participant-experimenter sex concordance influenced conditioning strength, reinforced expectations, and placebo effects in women but not in men. Our findings suggest that women experience larger conditioning effects, expectations and placebo response emphasizing the need to consider sex as a biological variable when placebo outcomes are parts of drug development trials and in pain management.

Frequent exposure to patient distress is associated with higher prevalence of clinician distress and symptoms of burnout. Patients with chronic pain often present with high levels of emotional distress. The current study examined the prevalence of burnout symptoms among a multidisciplinary sample of pain clinicians in Australia, the relationship between clinician confidence managing emotions and symptoms of burnout, and clinicians' perspectives on sources of stress and wellbeing at work. One hundred and seventy-six clinicians from 58 multidisciplinary pain clinics across Australia completed a survey including the 22-item Maslach Burnout Inventory, a measure of clinician confidence managing patient emotions and their own emotions, and open-ended questions probing clinician perspectives on sources of stress and wellbeing at work. High levels of emotional exhaustion and depersonalisation were reported by 21.6% and 14.2% of respondents, respectively. These burnout symptoms were predicted by clinician confidence managing their own emotions. Low levels of personal accomplishment were reported by 18.8% of respondents and were predicted by clinician confidence managing patients' emotions. Consistent with these quantitative findings, qualitative data revealed that emotionally challenging patient encounters were common sources of stress. Working with a multidisciplinary team and supportive relationships with colleagues were commonly reported sources of clinician wellbeing. The results of this study are discussed in light of previous reports of burnout in pain medicine physicians. Implications for clinician training in pain management and the prevention of burnout in pain clinicians are discussed.