Patients' and caregivers' maximum acceptable risk of death for non-curative gene therapy to treat Duchenne muscular dystrophy.

BACKGROUND: Gene therapy offers an etiologically targeted treatment for genetic disorders. Little is known about the acceptance of mortality risk among patients with progressive, fatal conditions. We assessed patients' and caregivers' maximum acceptable risk (MAR) of mortality for gene therapy when used to treat Duchenne muscular dystrophy (DMD). METHODS: The threshold technique was used to assess tolerance for mortality risks using a hypothetical vignette. Gene therapy was described as non-curative and resulting in a slowing of progression and with a 10-year benefit duration. MAR was analyzed using interval regression for gene therapy initiated "now"; in the last year of walking well; in the last year of being able to bring arms to mouth; and in newborns (for caregivers only). RESULTS: Two hundred eighty-five caregivers and 35 patients reported the greatest MAR for gene therapy initiated in last year of being able to lift arms (mean MAR 6.3%), followed by last year of walking well (mean MAR 4.4%), when used "now" (mean MAR 3.5%), and when used in the newborn period (mean MAR 2.1%, caregivers only). About 35% would accept ≥200/2000 risk in the last year of being able to lift arms. Non-ambulatory status predicted accepting 1.8 additional points in MAR "now" compared with ambulatory status (p = 0.010). Respondent type (caregiver or patient) did not predict MAR. CONCLUSION: In this first quantitative study to assess MAR associated with first-generation DMD gene therapy, we find relatively high tolerance for mortality risk in response to a non-curative treatment scenario. Risk tolerance increased with disease progression. Patients and caregivers did not have significantly different MAR. These results have implications for protocol development and shared decision making.

Randomized phase 2 trial and open-label extension of domagrozumab in Duchenne muscular dystrophy.

We report results from a phase 2, randomized, double-blind, 2-period trial (48 weeks each) of domagrozumab and its open-label extension in patients with Duchenne muscular dystrophy (DMD). Of 120 ambulatory boys (aged 6 to <16 years) with DMD, 80 were treated with multiple ascending doses (5, 20, and 40 mg/kg) of domagrozumab and 40 treated with placebo. The primary endpoints were safety and mean change in 4-stair climb (4SC) time at week 49. Secondary endpoints included other functional tests, pharmacokinetics, and pharmacodynamics. Mean (SD) age was 8.4 (1.7) and 9.3 (2.3) years in domagrozumab- and placebo-treated patients, respectively. Difference in mean (95% CI) change from baseline in 4SC at week 49 for domagrozumab vs placebo was 0.27 (-7.4 to 7.9) seconds (p = 0.94). There were no significant between-group differences in any secondary clinical endpoints. Most patients had ≥1 adverse event in the first 48 weeks; most were mild and not treatment-related. Median serum concentrations of domagrozumab increased with administered dose within each dose level. Non-significant increases in muscle volume were observed in domagrozumab- vs placebo-treated patients. Domagrozumab was generally safe and well tolerated in patients with DMD. Efficacy measures did not support a significant treatment effect. Clinicaltrials.gov identifiers: NCT02310763 and NCT02907619.

Patient and economic burdens of postherpetic neuralgia in China.

BACKGROUND: Little is known about the patient-reported and economic burdens of postherpetic neuralgia (PHN) among China's urban population. METHODS: This noninterventional study was conducted among adults ≥40 years with PHN who were seeking medical care at eight urban hospitals in China. At one study site, patients completed a questionnaire evaluating the patient-reported disease burden (N=185). The questionnaire consisted of validated patient-reported outcomes including the Brief Pain Inventory (BPI), 5-dimension, 3-level EuroQol (EQ-5D-3L), Medical Outcomes Study Sleep Scale, and Work Productivity and Activity Impairment Questionnaire for Specific Health Problems. Questions on non-pharmacologic therapy and out-of-pocket (OOP) expenses were also included. At all study sites, physicians (N=100) completed a structured review of patient charts (N=828), which was used to derive health care resource utilization and associated costs from the societal perspective. Annual costs in Chinese Yuan Renminbi (RMB) for the year 2016 were converted to US dollars (US$). RESULTS: Patients (N=185, mean age 63.0 years, 53.5% female) reported pain of moderate severity (mean BPI score 4.6); poor sleep quantity (average of 5.3 hrs per night) and quality; and poorer health status on the EQ-5D-3L relative to the general Chinese population. Respondents also reported average annual OOP costs of RMB 16,873 (US$2541) per patient, mainly for prescription PHN medications (RMB 8990 [US$1354]). Substantial work impairment among employed individuals resulted in annual indirect costs of RMB 28,025 (US$4221). In the chart review, physicians reported that patients (N=828) had substantial health resource utilization, especially office visits; 98% had all-cause and 95% had PHN-related office visits. Total annual direct medical costs were RMB 10,002 (US$1507), mostly driven by hospitalizations (RMB 8781 [US$1323]). CONCLUSION: In urban China, PHN is associated with a patient-reported burden, affecting sleep, quality-of-life, and daily activities including work impairment, and an economic burden resulting from direct medical costs and indirect costs due to lost productivity. These burdens suggest the need for appropriate prevention and management of PHN.

The Epidemiology of Herpes Zoster and Postherpetic Neuralgia in China: Results from a Cross-Sectional Study.

INTRODUCTION: Few studies have examined the epidemiology of herpes zoster (HZ) and postherpetic neuralgia (PHN) in China. The aim of this study was to estimate the prevalence of HZ and PHN in China, and to examine the clinical characteristics of patients identified with PHN. METHODS: This was a cross-sectional study conducted in 24 hospitals in seven cities in China. Prevalence of HZ and PHN was determined by physician (n = 100) chart review of patients (n = 36,170) aged ≥ 40 years seeking medical care over a 30- to 60-day period. The health history of patients identified with PHN was obtained and included time since diagnosis of HZ or PHN, time since onset of PHN-related pain, and the methods used for diagnosing HZ and PHN. RESULTS: The prevalence rates of HZ and PHN were 7.7% [95% confidence interval (CI) 7.5-8.0] and 2.3% (95% CI 2.2-2.5), respectively. Of patients with HZ, 29.8% developed PHN. Rates of HZ and PHN increased with age and were highest in patients aged ≥ 70 years (10.6% and 4.1%, respectively). The majority of patients with PHN were diagnosed with HZ (80.9%) and PHN (83.8%) for < 1 year, and had experienced PHN-related pain for < 1 year (80.5%). Patient description and clinical examination were most commonly used to diagnose HZ and PHN. CONCLUSION: These results provide current estimates of the prevalence of HZ and PHN in the general adult population in urban China. These rates are similar to previously reported rates in China and worldwide, and highlight the global nature of HZ and PHN. FUNDING: Pfizer Inc.

Priorities when deciding on participation in early-phase gene therapy trials for Duchenne muscular dystrophy: a best-worst scaling experiment in caregivers and adult patients.

PURPOSE: Several gene therapy trials for Duchenne muscular dystrophy initiated in 2018. Trial decision making is complicated by non-curative, time-limited benefits; the progressive, fatal course; and high unmet needs. Here, caregivers and patients prioritize factors influencing decision making regarding participation in early-phase gene therapy trials. METHODS: We conducted a best-worst scaling experiment among U.S. caregivers and adults with Duchenne (N = 274). Participants completed 11 choice sets, choosing features they cared about most and least when deciding whether to participate in a hypothetical gene therapy trial. We analyzed the data using sequential conditional logistic regression. RESULTS: Participants prioritized improved muscle function in trial decision making. Concerns about participation limiting later use of gene transfer and editing were also important, as were improved lung and heart function. Low risk of death fell near the middle. Participants cared least about muscle biopsies and potential for randomization to placebo. Adults with Duchenne and caregivers of non-ambulatory children significantly prioritized improved lung function compared to caregivers of ambulatory children. CONCLUSION: Our data demonstrate prioritization of anticipated benefits and opportunity costs relative to potential harms and procedures in gene therapy trial decision making. Such data inform protocol development, education and advocacy efforts, and informed consent.

A cost-consequence analysis of parecoxib and opioids vs opioids alone for postoperative pain: Chinese perspective.

PURPOSE: The use of parecoxib plus opioids for postoperative analgesia in noncardiac surgical patients seems to be cost-saving in Europe due to a reduction in opioid use and opioid-related adverse events. Given the lack of information on postoperative analgesic use in Asia, this study assessed the economic consequences of the addition of parecoxib to opioids vs opioids alone to treat postsurgical pain in China. METHODS: A cost-consequence economic evaluation assessed direct medical costs related to opioid-related clinically meaningful events (CMEs) utilizing dosing information and reported frequency of events from a Phase III, randomized, double-blind, global clinical trial (PARA-0505-069) of parecoxib plus opioids vs opioids alone for 3 days following major orthopedic, abdominal, gynecologic, or noncardiac thoracic surgery requiring general or regional anesthesia. The cost of CMEs was calculated using information on resource utilization and unit costs provided by a panel of clinical experts in China. Sensitivity analyses were performed to test the robustness of the results. RESULTS: Patients treated with parecoxib plus opioids reported fewer CMEs (mean 0.62 vs 1.04 events per patient [P<0.0001]) compared with opioids alone for the 3-day postoperative period. This suggested a potential savings of 356 Chinese yuan (¥) per patient over the 3 days (total cost of ¥1,418 for parecoxib plus opioids vs ¥1,774 with opioid use alone). CONCLUSION: Fewer CMEs with parecoxib plus opioids suggest a reduction in medical resource utilization and reduced costs compared to opioids alone when modeling analgesic use in non-cardiac surgery patients in China.

Epidemiology of physician-diagnosed neuropathic pain in Brazil.

OBJECTIVES: Estimate the prevalence of neuropathic pain (NeP) among chronic pain patients attending Brazilian hospitals and pain clinics in São Paulo, Ceara, and Bahia and explore clinical characteristics by subtypes: painful diabetic peripheral neuropathy (pDPN), central neuropathic pain (CNP), chronic low back pain with a neuropathic component (CLBP-NeP), postherpetic neuralgia (PHN), post-traumatic neuropathic pain (PTN), and post-surgical neuropathic pain (PSN). METHODS: Physicians screened patients reporting chronic pain for ≥3 months (n=2,118) for probable NeP, using the Douleur Neuropathique 4 questionnaire and physician assessment, and reported their NeP subtype(s), symptoms, and medications. Identified NeP patients completed a questionnaire including treatment experiences, quality of life EuroQol 5 Dimensions [EQ-5D]), pain severity and interference (Brief Pain Inventory [BPI]), and Work Productivity and Activity Impairment scales. Descriptive analyses were performed by NeP subtype. RESULTS: The prevalence of probable NeP was 14.5% (n=307). NeP patients were mostly female (80.5%), middle-aged (mean [M]=52.5, SD=13.9), and Pardo (44.3%). Of those diagnosed with an NeP subtype (n=209), the largest proportions were CLBP-NeP (36.8%), followed by pDPN (18.7%), CNP (17.7%), PTN (17.2%), PSN (13.4%), and PHN (3.3%). Across subtypes, the most widely reported symptoms were numbness (range: 62.2%-89.7%) and hyperalgesia (range: 32.1%-76.9%) and the most commonly prescribed pain analgesics were NSAID (range: 18.2%-57.1%), opioids (range: 0.0%-39.3%), and antiepileptics (range: 18.2%-57.1%). PTN and PSN patients reported the least favorable EQ-5D index scores (M=0.42, SD=0.19) and BPI-Pain Severity scores (M=7.0, SD=1.9), respectively. Those diagnosed with CNP had the least favorable BPI-Pain Interference scores (M=6.0, SD=2.7). Patients with PHN reported the least impairment based on EQ-5D index scores (M=0.60, SD=0.04). Those with pDPN had the most favorable BPI scores (BPI-Pain Severity: M=4.6, SD=2.3; BPI-Pain Interference: M=4.7, SD=2.7). CONCLUSION: Evaluation of chronic pain patients in Brazil yielded a 14.5% probable NeP prevalence. NSAIDs and opioids were commonly used, and there was a high incidence of NeP-related symptoms with varying levels of dysfunction across subtypes.

Characteristics of patients with neuropathic pain syndromes screened by the painDETECT questionnaire and diagnosed by physician exam.

BACKGROUND: The aim of this study was to identify the clinical characteristics, treatment usage, and health outcomes of US adults diagnosed with neuropathic pain (NeP) by experienced physicians. METHODS: Adults with scores exceeding the threshold for probable NeP (painDETECT ≥19) and diagnosed with NeP by a qualified physician completed a questionnaire that included comorbid conditions, pain symptoms and experiences, medication use, health status (3-level EuroQol 5 Dimensions (EQ-5D-3L]: health utilities index and visual analog scale), pain severity and interference with functioning (Brief Pain Inventory), and work and activity impairment (Work Productivity and Activity Impairment questionnaire). Descriptive analyses were performed for each NeP subtype. RESULTS: Participants (n=295) were predominantly female (64.4%), middle-aged (53.9%), and white (51.5%). Chronic low back pain was the most frequently diagnosed major NeP syndrome (n=166), followed by diabetic peripheral neuropathy (n=58), post-trauma neuropathy (n=47), post-surgical neuropathy (n=28), and central NeP (n=23). An additional 45 participants were diagnosed, but did not meet the criteria for the aforementioned subtypes. Participants could be diagnosed with multiple subtypes. Across each NeP subtype, patients reported high rates of comorbid disease, including arthritis (range: 39.1%-64.3%) and high blood pressure (range: 26.1%-69.0%), as well as symptomology that included numbness (range: 68.1%-91.4%) and changes in muscular strength (range: 24.1%-65.2%). The majority of patients reported back pain (range: 77.8%-95.7%) and arthritis/joint pain (range: 68.1%-78.6%). The most commonly reported types of NeP pain medication were non-steroidal anti-inflammatory drugs (range: 43.1%-70.2%), weak opioids (range: 22.2%-39.3%), and strong opioids (range: 8.7%-28.6%). All six NeP groups generally reported similar levels of dysfunction on all self-report measures. The most notable finding was that the EuroQol-5D-3L health utilities index scores for each of the six groups were lower than the US norms by a clinically important amount. CONCLUSION: These exploratory findings indicate that patients with NeP across different etiologies are medically complex and experience impaired function across multiple domains.

Characterizing classes of fibromyalgia within the continuum of central sensitization syndrome.

BACKGROUND: While fibromyalgia (FM) is characterized by chronic widespread pain and tenderness, its presentation among patients as a continuum of diseases rather than a single disease contributes to the challenges of diagnosis and treatment. The purpose of this analysis was to distinguish and characterize classes of FM within the continuum using data from chronic pain patients. METHODS: FM patients were identified from administrative claims data from the ProCare Systems' network of Michigan pain clinics between January 1999 and February 2015. Identification was based on either use of traditional criteria (ie, ICD-9 codes) or a predictive model indicative of patients having FM. Patients were classified based on similarity of comorbidities (symptom severity), region of pain (widespread pain), and type and number of procedures (treatment intensity) using unsupervised learning. Text mining and a review of physician notes were conducted to assist in understanding the FM continuum. RESULTS: A total of 2,529 FM patients with 79,570 observations or clinical visits were evaluated. Four main classes of FM patients were identified: Class 1) regional FM with classic symptoms; Class 2) generalized FM with increasing widespread pain and some additional symptoms; Class 3) FM with advanced and associated conditions, increasing widespread pain, increased sleep disturbance, and chemical sensitivity; and Class 4) FM secondary to other conditions. CONCLUSION: FM is a disease continuum characterized by progressive and identifiable classifications. Four classes of FM can be differentiated by pain and symptom severity, specific comorbidities, and use of clinical procedures.

Text Messaging to Improve Disease Management in Patients With Painful Diabetic Peripheral Neuropathy.

Purpose The purpose of the study was to determine the impact of educational text messages on diabetes self-management activities and outcomes in patients with painful diabetic peripheral neuropathy (pDPN). Methods Patients with pDPN identified from a large integrated health system who agreed to participate were randomized to 6 months of usual care (UC) or UC plus twice-daily diabetes self-management text messages (UC+TxtM). Outcomes included the Pain Numerical Rating Scale, Summary of Diabetes Self-Care Activities (SDSCA), questions on diabetes health beliefs, and glycated hemoglobin (A1C). Changes from baseline were evaluated at 6 months and compared between groups. Results Demographic characteristics were balanced between groups (N = 62; 53% female, mean age = 63 years, 94% type 2 diabetes), as were baseline measures. After 6 months, pain decreased with UC+TxtM from 6.3 to 5.5 and with UC from 6.5 to 6.0, with no difference between groups. UC+TxtM but not UC was associated with significant improvements from baseline on all SDSCA subscales. On diabetes health beliefs, UC+TxtM patients reported significantly increased benefits and reduced barriers and susceptibility relative to UC at 6 months. A1C declined in both groups, but neither change was significant relative to baseline. Conclusions Patients with pDPN who receive twice-daily text messages regarding diabetes management reported reduced pain relative to baseline, although this change was not significant compared with usual care. In addition, text messaging was associated with increased self-management activities and improved diabetes health beliefs and total self-care. These results warrant further investigation.

Clinical Characteristics of Fibromyalgia in a Chronic Pain Population.

OBJECTIVE: To compare fibromyalgia (FM) characteristics among patients identified in a community-based chronic pain cohort based on traditional International Classification of Diagnoses 9th revision (ICD-9) diagnostic coding, with that of patients identified using a novel predictive model. METHODS: This retrospective study used data collected from July 1999 to February 17, 2015, in multiple chronic pain clinics in the United States. Patients were assigned to the FM case group based on specific inclusion criteria using ICD-9 codes or, separately, from results of a novel FM predictive model that was developed using random forest and logistic regression techniques. Propensity scoring (1:1) matched FM patients (cases) to nonmalignant chronic pain patients without FM (controls). Patient-reported measures (eg, pain, fatigue, quality of sleep) and clinical characteristics (ie, comorbidities, procedures, and regions of pain) were outcomes for analysis. RESULTS: Nine ICD-9 clinical modification diagnoses had odds ratios with large effect sizes (Cohen's d > 0.8), demonstrating the magnitude of the difference between the FM and matched non-FM cohorts: chronic pain syndrome, latex allergy, muscle spasm, fasciitis, cervicalgia, thoracic pain, shoulder pain, arthritis, and cervical disorders (all P < 0.0001). Six diagnoses were found to have a moderate effect size (Cohen's 0.5 < d > 0.8): cystitis, cervical degeneration, anxiety, joint pain, lumbago, and cervical radiculitis. CONCLUSIONS: The identification of multiple comorbidities, diagnoses, and musculoskeletal procedures that were significantly associated with FM may facilitate differentiation of FM patients from other conditions characterized by chronic widespread pain. Predictive modeling may enhance identification of FM patients who may otherwise go undiagnosed.

Interpreting the Effectiveness of Opioids and Pregabalin for Pain Severity, Pain Interference, and Fatigue in Fibromyalgia Patients.

OBJECTIVE: To evaluate the effectiveness of opioids and/or pregabalin on patient-reported outcomes among fibromyalgia (FM) patients based on levels of improvement. METHODS: A total of 1,421 FM patients were identified, with 3,082 observational periods of opioids with or without pregabalin use between April 2008 and February 2015. Patients were categorized by opioids, and pregabalin with and without opioids; opioids were designated by morphine equivalent dose (MED) of ≤ 20 (low MED), > 20 to < 100 (moderate MED), ≥ 100 (high MED), and pregabalin doses of ≤ 150 mg, 151 to 300 mg, and 301 to 450 mg. Proportions of patients meeting clinically relevant thresholds of ≥ 30% and ≥ 50% improvement for pain interference (ability to enjoy life; activity; mood; relationships; sleep), pain severity, and fatigue were compared among treatments, and area under the curve (AUC) for improvement and worsening of effects was determined, enabling ranking of treatments. Further analysis compared pregabalin doses. RESULTS: Pregabalin without opioids resulted in the highest proportions of patients with ≥ 30% improvement on all pain items and pain interference with "ability to enjoy life," "activity" "mood," and "sleep." For the ≥ 50% threshold, pregabalin alone was highest for all pain interference items and for "average pain" and "worst pain." Pregabalin was consistently lowest across thresholds for fatigue, but showed better results combined with moderate MED opioids. Pregabalin doses recommended for treatment of FM (151 to 450 mg) generally resulted in the highest proportion of patients achieving thresholds relative to opioids. The AUC results were consistent with thresholds; pregabalin without opioids resulted in the greatest benefits with regard to improvement, with the highest ranking for overall improvement and overall effects. CONCLUSION: Pregabalin without opioids provided the most favorable outcomes overall based on ≥ 30% and ≥ 50% improvement thresholds and AUC, with support for moderate MED opioids + pregabalin in patients suffering from fatigue. While most patients took less than recommended pregabalin doses, higher doses may lead to improved outcomes.

The prevalence of probable neuropathic pain in the US: results from a multimodal general-population health survey.

BACKGROUND: The prevalence of neuropathic pain (NeP) has been estimated within specific health conditions; however, there are no published data on its broad prevalence in the US. The current exploratory study addresses this gap using the validated PainDetect questionnaire as a screener for probable NeP in a general-population health survey conducted with a multimodal recruitment strategy to maximize demographic representativeness. MATERIALS AND METHODS: Adult respondents were recruited from a combination of Internet panels, telephone lists, address lists, mall-based interviews, and store-receipt invitations using a random stratified-sampling framework, with strata defined by age, sex, and race/ethnicity. Older persons and minorities were oversampled to improve prevalence estimates. Results were weighted to match the total adult US population using US Census data. Demographic information was collected, and respondents who experienced physical pain in the past 12 months completed the PainDetect and provided additional pain history. A cutoff score of 19 or greater on the PainDetect was used to define probable NeP. RESULTS: A total of 24,925 respondents (average response rate 2.5%) provided demographic data (52.2% female, mean age 51.5 years); 15,751 respondents reported pain (63.7%), of which 2,548 (15.7%, 95% confidence interval 14.9%-16.5%) had probable NeP based on the PainDetect, which was 10% (95% confidence interval 9.5%-10.5%) of all respondents. Among those reporting pain, the prevalence of probable NeP among Blacks and Hispanics was consistently higher than Whites in each age- and sex group. The highest prevalence among those with pain was among male Hispanics 35-44 years (32.4%) and 45-54 years (24.2%) old. The most commonly used medications reported by those with probable NeP were nonsteroidal anti-inflammatory drugs (44.2%), followed by weak opioids (31.7%), antiepileptics (10.9%), and strong opioids (10.9%). CONCLUSION: This is the first study to provide an estimate of the prevalence of probable NeP in the US, showing significant variation by age and ethnicity.

A systematic review of the effectiveness of policies restricting access to pregabalin.

BACKGROUND: Formularies often employ restriction policies to reduce pharmacy costs. Pregabalin, an alpha-2-delta ligand, is approved for treatment of fibromyalgia (FM); neuropathic pain (NeP) due to postherpetic neuralgia (PHN), diabetic peripheral neuropathy (pDPN), spinal cord injury; and as adjunct therapy for partial onset seizures. Pregabalin is endorsed as first-line therapy for these indications by several US and EU medical professional societies. However, restriction policies such as prior authorization (PA) and step therapy (ST) often favor less costly generic pain medications over pregabalin. METHODS: A structured literature search (PubMed, past 11 years) was conducted to evaluate whether restriction policies against pregabalin support real-world economic and healthcare utilization benefits. RESULTS: Search criteria identified three claims analyses and a modeling study that evaluated patients with NeP and/or FM with and without PA restrictions; three other studies included patients with FM and NeP in plans with ST requirements, and one evaluated a mail order requirement program. All studies evaluated outcomes during follow-up periods of 6 months or longer. Overall, PA, ST, and mail order restriction policies effectively reduced pregabalin usage, but the effects were inconsistent with reducing pharmacy costs and were non-significant for total disease-related medical costs. Two studies (one PA; one ST) reported significantly higher disease-related costs in restricted plans. The modeling study failed to demonstrate cost savings with PA. Opioid usage was higher in PA-restricted plans (two studies). The US Centers for Disease Control and Prevention and several professional NeP guidelines recommend opioid use only in cases when other non-opioid pain therapies have proven ineffective. New US Government taskforce guidelines now seek to reduce opioid exposure. Additionally, in both ST studies, gabapentin utilization (a common ST edit) was significantly increased. Both studies had substantial proportions of FM and pDPN patients and the only pain condition gabapentin is approved to treat in the United States is PHN. CONCLUSION: PA and ST restriction policies significantly decrease utilization of pregabalin, but do not consistently demonstrate cost savings for US health plans. More research is needed to evaluate whether these policies may lead to increased opioid usage as found in some studies. TRIAL REGISTRATION: N/A.

Neuropathic pain: a narrative review of etiology, assessment, diagnosis, and treatment for primary care providers.

BACKGROUND: Neuropathic pain (NeP) is a distinct type of chronic pain that is a direct result of damage to the nervous system itself. Studies have shown that training on the topic of chronic pain in medical schools is lacking and many practitioners are not confident in their ability to effectively manage patients with such pain. AIMS: The purpose of this narrative review is to provide a brief high-level overview of NeP for primary healthcare providers that includes a discussion of mechanisms, prevalence, burden, assessment, and treatment. The information provided here should help primary care providers better understand this type of chronic pain.

Measurement properties of painDETECT: Rasch analysis of responses from community-dwelling adults with neuropathic pain.

BACKGROUND: painDETECT (PD-Q) is a self-reported assessment of pain qualities developed as a screening tool for pain of neuropathic origin. Rasch analysis is a strategy for examining the measurement characteristics of a scale using a form of item response theory. We conducted a Rasch analysis to consider if the scoring and measurement properties of PD-Q would support its use as an outcome measure. METHODS: Rasch analysis was conducted on PD-Q scores drawn from a cross-sectional study of the burden and costs of NeP. The analysis followed an iterative process based on recommendations in the literature, including examination of sequential scoring categories, unidimensionality, reliability and differential item function. Data from 624 persons with a diagnosis of painful diabetic polyneuropathy, small fibre neuropathy, and neuropathic pain associated with chronic low back pain, spinal cord injury, HIV-related pain, or chronic post-surgical pain was used for this analysis. RESULTS: PD-Q demonstrated fit to the Rasch model after adjustments of scoring categories for four items, and omission of the time course and radiating questions. The resulting seven-item scale of pain qualities demonstrated good reliability with a person-separation index of 0.79. No scoring bias (differential item functioning) was found for this version. CONCLUSIONS: Rasch modelling suggests the seven pain-qualities items from PD-Q may be used as an outcome measure. Further research is required to confirm validity and responsiveness in a clinical setting.

Perspectives on the impact of painful diabetic peripheral neuropathy in a multicultural population.

BACKGROUND: Since few studies have characterized painful diabetic peripheral neuropathy (pDPN) symptoms in multicultural populations, this study fielded a survey to better understand pDPN and its impact in African-American, Caucasian, and Hispanic populations. METHODS: Kelton fielded a survey by phone or Internet, in English or Spanish, among adults with pDPN symptoms in the United States between August and October 2015; African-Americans and Hispanics were oversampled to achieve at least 500 subjects for each group. Patients were required to have been diagnosed with pDPN or score ≥ 3 on ID Pain validated screening tool. The survey elicited information on pDPN symptoms and interactions with healthcare providers (HCPs), and included the Brief Pain Inventory and pain-specific Work Productivity and Assessment Questionnaire (WPAI:SHP). RESULTS: Respondents included 823 Caucasians, 525 African-Americans, and 537 Hispanics; approximately half of African-Americans and Hispanics were <40 years of age, vs 12% of Caucasians. Pain was less likely to be rated moderate or severe by African-Americans (65%) and Hispanics (49%) relative to Caucasians (87%; p < 0.05). African-Americans and Hispanics were less likely than Caucasians to report experiencing specific pDPN sensory symptoms. Significantly fewer African-Americans and Hispanics reported receiving a pDPN diagnosis relative to Caucasians (p < 0.05), and higher proportions of African-Americans and Hispanics reported difficulty communicating with their HCP (p < 0.05). WPAI:SHP activity impairment was lower in Hispanics (43%) relative to African-Americans (53%) and Caucasian (56%; p < 0.05). CONCLUSIONS: Multicultural patients reported differences in pDPN symptoms and pain relative to Caucasians, and fewer received a pDPN diagnosis. While further evaluation is needed to understand these differences, these data suggest a need to broaden pDPN educational initiatives to improve patient-HCP dialogue and encourage discussion of pDPN symptoms and their impact in a multicultural setting.

Effects of Pregabalin in Patients with Neuropathic Pain Previously Treated with Gabapentin: A Pooled Analysis of Parallel-Group, Randomized, Placebo-controlled Clinical Trials.

OBJECTIVES: This analysis compared the therapeutic response of pregabalin in patients with neuropathic pain (NeP) who had been previously treated with gabapentin to the therapeutic response in patients who had not received gabapentin previously. METHODS: Data were pooled from 18 randomized, double-blind, placebo-controlled trials of pregabalin in patients with NeP. Pregabalin-mediated changes in pain and pain-related sleep interference scores, patient global impression of change scores at endpoint, and the occurrence of adverse events were compared between patients who had received gabapentin previously (+GBN) and patients who had not received gabapentin previously (-GBN). RESULTS: There were no significant differences between the -GBN and +GBN cohorts with regard to the extent of pain relief and relief of pain-related sleep interference for any dose of pregabalin (150, 300, 600, or 150 to 600 mg/day) at any time point (6, 8, or 12 weeks). Additionally, there was no significant difference in the distribution of patient global impression of change scores at study endpoint, or the occurrence of adverse events, between the -GBN and +GBN cohorts. DISCUSSION: The findings presented here support the idea that pregabalin may be used successfully to treat patients with NeP who may be refractory, respond inadequately, or are intolerant to gabapentin. These findings highlight the importance of tailoring treatment of NeP based on individual patient response to different treatments, including the trial of multiple agents within the same mechanistic class.

Psychometric validation of the electronic chronic pain questions (eCPQ) in a primary care setting.

OBJECTIVE: Collecting data that helps evaluate different types of pain may improve physicians' decision-making with regard to treatment selection and on-going monitoring of patients. To date, no chronic pain assessments have been widely implemented in primary care. The aim of this study was to psychometrically validate the electronic Chronic Pain Questions (eCPQ) in a primary care setting. RESEARCH DESIGN AND METHODS: All men and women ≥18 years arriving at two similar primary care clinics in southeastern Michigan were invited to participate. Clinic staff verbally administered the eCPQ to patients and recorded their answers into the electronic medical record (EMR) prior to physician consultation with results available for physician review. Concurrent validity was assessed using Spearman correlations between eCPQ and patient-completed ancillary measures. Known-group validity was assessed by stratifying patients on self-reported chronic pain as well as by pain diagnosis (i.e. ICD-9 codes). To compare patients with chronic pain versus no chronic pain t-tests and chi-square tests were performed. Reproducibility was assessed between interviewer- and self-administration over time. RESULTS: A total of 534 patients were invited to participate and 455 patients consented to take part in the study (85.2% response rate); 395 patients had analyzable eCPQ data; 70.1% were Caucasian; 68.1% female; mean age was 43.4; 52.7% (n = 208) self-reported chronic pain. Correlations between eCPQ and ancillary measures supported concurrent validity. Excellent discrimination between groups was evidenced based on self-reported chronic pain and ICD-9 diagnosis. Patients with self-reported chronic pain reported significantly (p < .0001) higher pain ratings and greater interference with usual activities, sleep, and mood than those without chronic pain. Test-retest reliability between modes (interviewer- vs. self-administration) was excellent as was reproducibility based on self-administration of the eCPQ at two separate time points. Key limitations: Discriminant validity was determined by comparing participants based on ICD codes. Utilizing ICD codes to identify individuals with chronic pain may not be a reliable approach as it is dependent upon providers accurately and consistently entering chronic pain diagnoses in the EMR. CONCLUSIONS: The eCPQ has sound psychometric measurement properties, including concurrent validity, discriminant validity, and reproducibility. The eCPQ appears to be useful to identify patients with chronic pain and to assess and monitor symptoms over time.