Human Studies

We tested whether aerobic exercise training altered morphine analgesic responses or reduced morphine dosages necessary for adequate analgesia. Chronic back pain patients were randomized to an 18-session aerobic exercise intervention (n = 38) or usual activity control (n = 45). Before and after the intervention, participants underwent three laboratory sessions (double-blinded, crossover) to assess effects of saline placebo, i.v. morphine (0.09 mg/kg), and i.v. naloxone (12 mg) on low back pain and evoked heat pain responses. Differences in evoked and back pain measures between the placebo and morphine conditions indexed morphine analgesia, with pre-post intervention changes the primary outcome. Endogenous opioid (EO) analgesia was indexed by differences in evoked and low back pain measures between the naloxone and placebo conditions. A Sex X Intervention interaction on the analgesic effects of morphine on VAS back pain intensity was observed (p = .046), with a similar trend for evoked pain threshold (p = .093). Male exercisers showed reduced morphine analgesia pre-post intervention whereas male controls showed increased analgesia (with no differences in females). Of clinical significance were findings that relative to the control group, aerobic exercise produced analgesia more similar to that observed after receiving ≈7 mg morphine pre-intervention (p's < .045). Greater pre-post intervention increases in EO function (from any source) were significantly associated with larger pre-post intervention decreases in morphine analgesia (p's < .046). The overall pattern of findings suggest that regular aerobic exercise has limited direct effects on morphine responsiveness, reducing morphine analgesia in males only.

Back pain is a leading cause of disability worldwide and is common in older adults. No clinical prediction models for poor long-term outcomes have been developed in older patients with back pain. This study aimed to develop and internally validate three clinical prediction models for non-recovery in this population. A prospective cohort study in general practice was conducted (BACE, Netherlands), including 675 patients >55 years with a new episode of care for back pain. Three definitions of non-recovery were used combining 6- and 12-month follow-up data: 1) persistent back pain; 2) persistent disability; 3) perceived non-recovery. Sample size calculation resulted in a maximum of 14 candidate predictors that were selected from back pain prognostic literature and clinical experience. Multivariable logistic regression was used to develop the models (backward selection procedure). Models' performance was evaluated with explained variance (Nagelkerke's R2), calibration (Hosmer-Lemeshow test), and discrimination (AUC) measures. The models were internally validated in 250 bootstrapped samples to correct for over-optimism. All three models displayed good overall performance during development and internal validation (i.e. R2>30%; AUC>0.77). The model predicting persistent disability performed best, showing good calibration, discrimination (AUC 0.86, 95%CI 0.83-0.89; optimism-adjusted AUC 0.85), and explained variance (R2 49%, optimism-adjusted R2 46%). Common predictors in all models were: age, chronic duration, disability, a recent back pain episode, and patients' recovery expectations. Spinal morning stiffness and pain during spinal rotation were included in two out of three models. These models should be externally validated before being used in a clinical primary care setting.

Spinal infections represent a therapeutic challenge. The often protracted course of the disease is accompanied by pain, which can lead to a chronic pain experience even after the infectious disease has been treated successfully. The aim of this study was to investigate possible risk factors of pain chronification.

To investigate whether illness perceptions, measured with the Brief Illness Perception Questionnaire, are an independent predictor of chronic low back pain and pain-related disability at 12 weeks.

To study differences in pain reports between patients with ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA), and to assess how pain sensitivity measures associate with disease and health outcomes.

Managing chronic musculoskeletal problems usually focuses on pain control using medications, but outcomes are often unsatisfactory and sometimes harmful. Information on a patient's health-related quality of life (HRQOL) may trigger a doctor to tailor management improving quality of life. The aim of this trial is to find out whether routine measurement and reporting of a patient's EuroQoL 5-Dimension 5-Level (EQ-5D-5L) HRQOL data using an electronic platform can improve HRQOL and pain in patients with chronic knee or back problems in primary care. We will also assess the acceptability of routine electronic measurements and reporting of the EQ-5D-5L in primary care settings.