The importance of catastrophizing for successful pharmacological treatment of peripheral neuropathic pain.

OBJECTIVE: Catastrophizing may be a negative predictor of pain-related outcomes. We evaluated the impact of catastrophizing upon success of first-line pharmacotherapy in the management of neuropathic pain (NeP) due to peripheral polyneuropathy. METHODS: Patients with confirmed NeP with NeP Visual Analog Scale (VAS) pain severity score ≥4 (0-10 scale) completed the Coping Strategies Questionnaire (CSQ) catastrophizing subscale at baseline. Pharmacological therapy consisting of first-line agents gabapentin, pregabalin, or a tricyclic antidepressant was initiated. Other measures examined included the Karnofsky Performance Scale, Beck Depression Inventory, EuroQol Quality of Life Health Questionnaire, and Modified Brief Pain Inventory. At 3 and 6 months, questionnaires were repeated and adverse effect reporting was completed. Outcome measures assessed were pharmacotherapy success (≥30% relief of NeP) and tolerability over 6 months of follow-up. Bivariate relationships using Pearson product-moment correlations were examined for baseline CSQ catastrophizing subscale score and the change in the NeP VAS scores and medication discontinuation. RESULTS: Sixty-six patients were screened, 62 subjects participated, and 58 subjects (94%) completed the final follow-up visit. Greater catastrophizing was associated with poor pain relief response and greater likelihood of discontinuation of pharmacotherapy, reports of greater disability, and impaired quality of life. Duration of pain was negatively associated with likelihood of pharmacotherapy success. CONCLUSION: Catastrophizing exerts maladaptive effects on outcomes with pharmacotherapy in NeP patients. Detection of catastrophizing during clinical visits when pharmacological therapy is being considered can be a predictive factor for patient outcomes.

Public knowledge and perceptions of connected health.

RATIONALE, AIMS AND OBJECTIVES: This study aims to examine the public's knowledge and perceptions of connected health (CH). METHODS: A structured questionnaire was administered by face-to-face interview to an opportunistic sample of 1003 members of the public in 11 shopping centres across Northern Ireland (NI). Topics included public knowledge of CH, opinions about who should provide CH and views about the use of computers in health care. Multivariable analyses were conducted to assess respondents' willingness to use CH in the future. RESULTS: Sixty-seven per cent of respondents were female, 31% were less than 30 years old and 22% were over 60 years. Most respondents had never heard of CH (92%). Following a standard definition, the majority felt CH was a good idea (≈90%) and that general practitioners were in the best position to provide CH; however, respondents were equivocal about reductions in health care professionals' workload and had some concerns about the ease of device use. Factors positively influencing willingness to use CH in the future included knowledge of someone who has a chronic disease, residence in NI since birth and less concern about the use of information technology (IT) in health care. Those over 60 years old or who felt threatened by the use of IT to store personal health information were less willing to use CH in the future. CONCLUSION: Increased public awareness and education about CH is required to alleviate concerns and increase the acceptability of this type of care.

A randomized, single-blind, controlled, parallel assignment study of exercise versus education as adjuvant in the treatment of peripheral neuropathic pain.

OBJECTIVE: Some forms of chronic pain are receptive to exercise therapy for maintenance of pain relief. We evaluated the impact of a balanced exercise program in the management of human peripheral neuropathic pain compared with an educational intervention. METHODS: This was a single-center, randomized, single-blind, controlled study using an intention-to-treat protocol. Patients with confirmed neuropathic pain and a pain score ≥4 (0 to 10 scale) on visual analog scale (VAS) continued their regular pain therapies and were randomized to 6 months of either a balanced exercise program or an educational program. VAS for pain severity was the primary outcome variable. Characteristics of pain, function, mood, anxiety, sleep, and quality of life along with Single Stage Treadmill Walking Test calculating maximal oxygen consumption (VO2) formed the secondary outcome measures. RESULTS: Seventy-eight patients were screened and 54 participated, with 28 randomized to exercise and 26 randomized to education. A total of 19 (68%) and 20 patients (77%) completed exercise and education, respectively. VAS scores improved 17% for the exercise group as compared with 9% for the education group (P=0.08). The only secondary outcome measure demonstrating improvement was VO2, which improved in exercise participants (25.6±4.5 mL/kg/min at baseline vs. 28.9±3.8 mL/kg/min at 6 mo). DISCUSSION: A balanced exercise program was beneficial for exercise capacity, but produced only a medium-sized effect without statistical significance. A small sample size and unexpectedly high dropout rates may have limited our ability to demonstrate statistically significant improvement in pain relief.

Presence of neuropathic pain may explain poor performances on olfactory testing in diabetes mellitus patients.

Olfactory dysfunction in neurodegenerative conditions such as Parkinson's syndrome and Alzheimer's disease can hallmark disease onset. We hypothesized that patients with diabetes mellitus, a condition featuring peripheral and central neurodegeneration, would have decreased olfaction abilities. We examined participants with diabetic peripheral neuropathy, participants with diabetes without diabetic peripheral neuropathy, and control participants in blinded fashion using standardized Sniffin' Sticks. Diabetic peripheral neuropathy severity was quantified using the Utah Early Neuropathy Scale. Further subcategorization of diabetic peripheral neuropathy based on presence of neuropathic pain was performed with Douleur Neuropathique 4 Questionnaires. Participants with diabetes had decreased olfactory sensitivity, impaired olfactory discrimination abilities, and reduced odor identification skills when compared with controls. However, loss of olfaction ability was, at least partially, attributed to presence of neuropathic pain on subcategory assessment, although pain severity was not associated with dysfunction. Those participants with diabetes without diabetic peripheral neuropathy and those with diabetic peripheral neuropathy without neuropathic pain had similar olfactory function as controls in general. The presence of neuropathic pain, associated with limited attention and concentration, may explain at least a portion of the olfactory dysfunction witnessed in the diabetic patient population.

Increased gait variability in diabetes mellitus patients with neuropathic pain.

AIMS: Gait dysfunction in subjects with diabetes mellitus (DM) contributes to falling and subsequent injuries. Using a portable device (GaitMeter™), we measured gait parameters in DM patients with and without diabetic peripheral neuropathy (DPN) during flat surface walking. We hypothesized that DM patients with DPN and neuropathic pain (NeP) would have greater gait step variability than those with DPN without NeP. METHODS: Subjects with DPN and at least moderate NeP (DPN-P), DPN without NeP (DPN-NoP), DM without DPN, and control subjects without DM were assessed. Our outcome measure was gait variability for step length and velocity. DPN severity was quantified using the Toronto Clinical Scoring System and the Utah Early Neuropathy Score. Falls and their outcomes were retrospectively quantified. RESULTS: Each cohort contained≥20 subjects. Durations of DM and HbA1C were greatest amongst DPN cohorts. DPN-P participants had greater variability of step length and step velocity, except for DM only participants. DPN-P participants also reported greater risk of hospitalizations for fall-related injuries, and greater fear of falling. Modest negative relationships emerged for step length with step velocity, reported falls and pain severity. CONCLUSIONS: NeP contributes to gait variability, potentially contributing to the risk of falling in DM patients.

An enriched-enrolment, randomized withdrawal, flexible-dose, double-blind, placebo-controlled, parallel assignment efficacy study of nabilone as adjuvant in the treatment of diabetic peripheral neuropathic pain.

Cannabinoids are emerging as potential options for neuropathic pain treatment. This study evaluated an oral cannabinoid, nabilone, in the treatment of refractory human diabetic peripheral neuropathic pain (DPN). We performed a single-center, randomized, double-blind, placebo-controlled, flexible-dose study with an enriched enrollment randomized withdrawal design. DPN subjects with a pain score ≥ 4 (0-10 scale) continued regular pain medications and were administered single-blinded adjuvant nabilone for 4 weeks. Subjects achieving ≥ 30% pain relief (26/37) were then randomized and treated with either flexible-dose nabilone 1-4 mg/day (n=13) or placebo (n=13) in a further 5-week double-blind treatment period, with 30% (11/37) of subjects deemed run-in-phase nabilone nonresponders. For nabilone run-in-phase responders, there was an improvement in the change in mean end-point neuropathic pain vs placebo (mean treatment reduction of 1.27; 95% confidence interval 2.29-0.25, P=0.02), with an average nabilone dose at end point of 2.9 ± 1.1mg/day, and improvements from baseline for the anxiety subscale of the Hospital Anxiety and Depression Scale, the Medical Outcomes Study sleep scale problems index, and the European Quality of Life-5-Domains index score (each P<0.05). Nabilone run-in-phase responders reported greater global end-point improvement with nabilone than with placebo (100% vs 31%; P<0.05). Medication-related confusion led to discontinuation in 2/37 subjects during single-blind nabilone treatment. Potential unmasking occurred in 62% of both groups. Flexible-dose nabilone 1-4 mg/day was effective in relieving DPN symptoms, improving disturbed sleep, quality of life, and overall patient status. Nabilone was well tolerated and successful as adjuvant in patients with DPN.

The impact of enrollment in a specialized interdisciplinary neuropathic pain clinic.

BACKGROUND: Chronic pain clinics have been created because of the increasing recognition of chronic pain as a very common, debilitating condition that requires specialized care. Neuropathic pain (NeP) is a multifaceted, specialized form of chronic pain that often requires input from multiple disciplines for assessment and management. OBJECTIVE: To determine the impact of an interdisciplinary clinic for evaluation and treatment of patients with NeP. METHODS: Patients with heterogeneous etiologies for NeP were prospectively evaluated using an interdisciplinary approach every six months. Diagnostic evaluation, comorbidity evaluation, education, and pharmacological and/or nonpharmacological management were completed. Severity (visual analogue scale) and features of pain (Modified Brief Pain Inventory), sleep difficulties (Medical Outcomes Study - Sleep Scale), mood/anxiety disruption (Hospital Anxiety and Depression Scale), quality of life (European Quality-of-Life Five-Domain index), health care resources use, patient satisfaction (Pain Treatment Satisfaction Scale and Neuropathic Pain Symptom Inventory) and self-perceived change in well-being (Patient Global Impression of Change scale) were examined at each visit. RESULTS: Pain severity only decreased after one year of follow-up, while anxiety and quality- of-life indexes improved after six months. Moderate improvements of sleep disturbance, less frequent medication use and reduced health care resource use were observed during enrollment at the NeP clinic. DISCUSSION: Despite the limitations of performing a real-world, uncontrolled study, patients with NeP benefit from enrollment in a small interdisciplinary clinic. Education and a complete diagnostic evaluation are hypothesized to lead to improvements in anxiety and, subsequently, pain severity. Questions remain regarding the long-term maintenance of these improvements and the optimal structure of specialized pain clinics.