Cortical function and sensorimotor plasticity predict future low back pain after an acute episode: the UPWaRD prospective cohort study

Predicting the development of chronic low back pain (LBP) at the time of an acute episode remains challenging. The Understanding persistent Pain Where it ResiDes (UPWaRD) study aimed to identify neurobiological and psychological risk factors for chronic LBP. Individuals with acute LBP (N=120) participated in a prospective cohort study with six-month follow-up. Candidate predictors were selected from the neurobiological (e.g. sensorimotor cortical excitability assessed by sensory and motor evoked potentials, Brain Derived Neurotrophic Factor genotype), psychological (e.g. depression and anxiety), symptom-related (e.g. LBP history) and demographic domains. Analyses involved multivariable linear regression models with pain intensity or disability degree as continuous variables. Secondary analyses involved a multivariable logistic model with presence of low back pain at six months (thresholding pain intensity and disability degree) as a dichotomous variable. Lower sensory cortex and corticomotor excitability, higher baseline pain intensity, higher depression, stress and pain catastrophizing were the strongest predictors (R2=0.47) of pain intensity at six months. Older age and higher pain catastrophizing were the strongest predictors (R2=0.30) of disability at six months. When LBP outcome was dichotomised, sensory cortex and corticomotor excitability, BDNF genotype, depression and anxiety, LBP history and baseline pain intensity, accurately discriminated those who did and did not report LBP at six months (c-statistic 0.91). This study identifies novel risk factors for future LBP after an acute episode that can predict an individuals pain intensity and level of disability at six-month follow-up, and accurately discriminate between those who will and will not report LBP at six months.

Individual responses to topical ibuprofen gel or capsaicin cream for painful knee osteoarthritis: a series of n-of-1 trials

Objectives To determine individual responses to ibuprofen gel or capsaicin cream for painful, radiographic knee OA using a series of n-of-1 trials. Methods Twenty-two participants were allocated 5% ibuprofen gel (A) and 0.025% capsaicin cream (B) in random sequence (AB or BA). Patients underwent up to 3 treatment cycles, each comprising one treatment for 4 weeks, an individualized washout period (maximum 4 weeks), then the other treatment for 4 weeks. Differential (ibuprofen or capsaicin) response was defined when change-from-baseline pain intensity scores (0–10 NRS) differed by ≥1 between treatments in ≥2 cycles within a participant. Results A total of 104 treatment periods were aggregated. Mean pain reduction was 1.2 (95% CI: 0.5, 1.8) on ibuprofen and 1.6 (95% CI: 0.9, 2.4) on capsaicin (P = 0.221). Of 22 participants, 4 (18%) had a greater response to ibuprofen, 9 (41%) to capsaicin, 4 (18%) had similar responses, and 5 (23%) were undetermined. Conclusion Irrespective of equal efficacy overall, 59% of people displayed a greater response to one treatment over the other. Patients who do not benefit from one type of topical treatment should be offered to try another, which may be more effective. N-of-1 trials are useful to identify individual response to treatment. Clinical trial registration https://clinicaltrials.gov, NCT03146689

The Patient with Difficult Cancer Pain

Most patients with cancer pain can be managed with relatively simple methods using oral analgesics at relatively low doses, even for prolonged periods of time. However, in some clinical conditions pain may be more difficult to manage. Various factors can interfere with a desirable and favorable analgesic response. Data from several studies assessing factors of negative pain prognosis have indicated that neuropathic pain, incident pain, psychological distress, opioid addiction, and baseline pain intensity were associated with more difficult pain control. In this narrative review, the main factors that make the therapeutic response to opioids difficult are examined.

Pain control in chronic, refractory CRPS by continuous brachial plexus analgesia

We report on the outcomes of treatment for severe pain associated with long-standing, refractory CRPS in 10 female patients by continuous brachial plexus analgesia. The duration of the disease prior to treatment was 3.5 years on average, and mean baseline pain intensity was 8.3 on a numeric analogue scale (NRS). All patients met the Budapest criteria for the diagnosis of CRPS. A spinal catheter was implanted into the brachial plexus via an open axillary approach. Results: Each patient underwent a mean of 4.4 (range 2–8) spinal catheter implantations. A rapid and strong analgesic effect was observed immediately after the injection of bupivacaine solution was started: Pain decreased from a mean of 8.3 to 1.6. The duration of maintaining the catheter in the brachial plexus and achieving effective analgesia was 5.3 months (range 2–12). After the removal of the catheter, the pain returned to baseline. No patient achieved a permanent, or at least partial, reduction of pain after completing this therapy.

Subgroup analysis by baseline pain intensity (BPI) and analgesic use (BAU) in NAPOLI-1: A phase III study of liposomal irinotecan (nal IRI)±5-fluorouracil/ leucovorin (5-FU/LV) in patients (pts) with metastatic pancreatic ductal adenocarcinoma (mPDAC) previously treated with gemcitabine-based therapy.

379 Background: We report an exploratory, post hoc subgroup analysis in pts with BPI and BAU data receiving nal-IRI+5-FU/LV, nal-IRI or 5-FU/LV in NAPOLI-1 (NCT01494506). In this pivotal trial, nal-IRI+5-FU/LV improved median OS (mOS) vs. 5-FU/LV (6.1 vs. 4.2 mo [HR=0.67; p=0.012]). Methods: BPI/BAU included an average of 3-7 days pt-recorded data before randomisation. Greater values indicated greater pain for BPI using a 100 mm visual analogue scale. BAU was converted to morphine equivalent mg/day. Results: Of 417 ITT pts, 295 had BPI and 299 had BAU data. Mean and median BPI were 28.6 and 25.0, respectively, and BAU were 33.3 and 8.1 mg/day, respectively. The percentage of pts with KPS ≥ 80 was higher in ≤ mean/≤ median (n=159/148) BPI groups vs. > mean/> median (n=136/147) BPI groups (96-97 vs. 83%) and in ≤mean/≤median (n=207/150) BAU groups vs. > mean/> median (n=92/149) BAU groups (95-97 vs. 82-85%). mOS and median PFS (mPFS) were higher for nal-IRI+5-FU/LV vs 5-FU/LV in all groups, with ≤ mean/≤ median BPI or BAU showing better outcomes vs. > mean/> median BPI or BAU (Table). Conclusions: BPI and BAU appear to have a prognostic effect on outcomes in mPDAC pts in the NAPOLI-1 study. No predictive effect was observed, with nal-IRI+5-FU/LV showing higher mOS vs. 5-FU/LV in all groups. Clinical trial information: NCT01494506. [Table: see text]

Breakthrough Pain in Patients with Controlled or Uncontrolled Pain: An Observational Study

BACKGROUND: Breakthrough pain (BTP) is traditionally defined as a pain exacerbation in patients with chronic controlled pain. However, this definition has recently been challenged.OBJECTIVES: To evaluate the prevalence of unsatisfactory control in patients with chronic cancer pain, and investigate the frequency and intensity of BTP episodes.METHODS: A total of 665 patients with chronic cancer pain attending 21 pain therapy units in Italy were evaluated for baseline pain intensity and number of BTP episodes over a 30-day period. All patients started, continued or modified treatment for BTP at enrollment, according to medical judgment.RESULTS: The number of BTP events was higher in patients with uncontrolled baseline pain, although the intensity and duration of episodes were similar. In patients with uncontrolled baseline pain, the number of events decreased with time and reached values comparable with those reported in patients with controlled pain. Both the intensity of the pain and the duration of the BTP events exhibited similar values in the two groups at all time points, following increased monitoring and the prescription of analgesic medication.CONCLUSION: Patients with uncontrolled baseline pain experienced BTP flares with higher frequency, but similar intensity and duration with respect to patients with controlled pain at baseline. Notably, a close follow-up and adequate management of the BTP episodes led to an improvement of BTP in the observed patients.