The postmastectomy pain syndrome: an epidemiological study on the prevalence of chronic pain after surgery for breast cancer

The prevalence of the postmastectomy pain syndrome (PMPS) and its clinical characteristics was assessed in a group of patients who had undergone surgery for breast cancer at the Department of Surgery, Odense University Hospital, within the period of 1 May 2003 to 30 April 2004. The study included 258 patients and a reference group of 774 women. A questionnaire was mailed to the patients 1½ year after surgery and to the women in the reference group. The PMPS was defined as pain located in the area of the surgery or ipsilateral arm, present at least 4 days per week and with an average intensity of at least 3 on a numeric rating scale from 0 to 10. The prevalence of PMPS was found to be 23.9%. The odds ratio of developing PMPS was 2.88 (95% confidence interval 1.84–4.51). Significant risk factors were as follows: having undergone breast surgery earlier (OR 8.12), tumour located in the upper lateral quarter (OR 6.48) and young age (OR 1.04). This study shows that, although recent advances in the diagnostic and surgical procedures have reduced the frequency of the more invasive surgical procedures, there still is a considerable risk of developing PMPS after treatment of breast cancer

Epidemiology of physician-diagnosed neuropathic pain in Brazil

Margarita Udall,1 Ian Kudel,2 Joseph C Cappelleri,3 Alesia Sadosky,1 Kristen King-Concialdi,2 Bruce Parsons,1 Patrick Hlavacek,1 Markay Hopps,1 P Arline Salomon,4 Marco D DiBonventura,2 Patricia Clark,5,6 João Batista Santos Garcia7 1Pfizer Inc, New York, NY, USA; 2Health Outcomes Practice, Kantar Health, New York, NY, USA; 3Pfizer Inc, Groton, CT, USA; 4Pfizer Inc, Bosques de las Lomas, Mexico; 5Clinical Epidemiology Unit, Hospital Infantil de México Federico Gómez, Mexico City, Mexico; 6Faculty of Medicine UNAM, Mexico City, Mexico; 7Pain and Palliative Care Department, Federal University of Maranhão, Maranhão, 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. Keywords: neuropathic pain, Brazil, quality of life, pain, work productivity and activity impairmen

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

Marco D DiBonaventura,1 Alesia Sadosky,2 Kristen Concialdi,1 Markay Hopps,2 Ian Kudel,1 Bruce Parsons,2 Joseph C Cappelleri,3 Patrick Hlavacek,2 Andrea H Alexander,2 Brett R Stacey,4 John D Markman,5 John T Farrar6 1Health Outcomes Practice, Kantar Health, 2Pfizer Inc, New York, NY, 3Pfizer Inc, Groton, CT, 4University of Washington, Seattle, WA, 5University of Rochester School of Medicine and Dentistry, Rochester, NY, 6University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, US 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. Keywords: neuropathic pain, prevalence, pain types, epidemiolog

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

Ian Kudel,1 Markay Hopps,2 Joseph C Cappelleri,3 Alesia Sadosky,2 Kristen King-Concialdi,1 Ryan Liebert,1 Bruce Parsons,2 Patrick Hlavacek,2 Andrea H Alexander,2 Marco D DiBonaventura,4 John D Markman,5 John T Farrar,6 Brett R Stacey7 1Health Outcomes Practice, Kantar Health, New York, NY, USA; 2Pfizer Inc, New York, NY, USA; 3Pfizer Inc, Groton, CT, USA; 4Pfizer Inc, New York, NY, USA; 5University of Rochester Medical Center School of Medicine and Dentistry, Rochester, NY, USA; 6Department of Biostatistics and Epidemiology University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA; 7UW Center for Pain Relief, University of Washington, Seattle, WA, USA 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. Keywords: activity impairment, functional status, health-related quality of life, neuropathic pain, pain medication use, physician diagnosis, work impairmen