Mélanie Racine

A systematic literature review of 10 years of research on sex/gender and experimental pain perception – Part 1: Are there really differences between women and men?

Summary Relatively limited support is provided to the hypothesis that healthy women have greater pain sensitivity than men in most experimental pain modalities. Abstract The purpose of this systematic review was to summarize and critically appraise the results of 10 years of human laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian and conducted in multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. The first set of results (122 articles), which is presented in this paper, examined sex difference in the perception of laboratory‐induced thermal, pressure, ischemic, muscle, electrical, chemical, and visceral pain in healthy subjects. This review suggests that females (F) and males (M) have comparable thresholds for cold and ischemic pain, while pressure pain thresholds are lower in F than M. There is strong evidence that F tolerate less thermal (heat, cold) and pressure pain than M but it is not the case for tolerance to ischemic pain, which is comparable in both sexes. The majority of the studies that measured pain intensity and unpleasantness showed no sex difference in many pain modalities. In summary, 10 years of laboratory research have not been successful in producing a clear and consistent pattern of sex differences in human pain sensitivity, even with the use of deep, tonic, long‐lasting stimuli, which are known to better mimic clinical pain. Whether laboratory studies in healthy subjects are the best paradigm to investigate sex differences in pain perception is open to question and should be discussed with a view to enhancing the clinical relevance of these experiments and developing new research avenues.

A systematic literature review of 10 years of research on sex/gender and pain perception - Part 2: Do biopsychosocial factors alter pain sensitivity differently in women and men?

Summary Ecological validity of laboratory findings in healthy humans about the role of certain biopsychological factors on sex differences in pain perception needs to be assessed/improved. Abstract This systematic review summarizes the results of 10 years of laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian to access multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. The second set of results presented in this review (129 articles) examined various biopsychosocial factors that may contribute to differences in pain sensitivity between healthy women and men. The results revealed that the involvement of hormonal and physiological factors is either inconsistent or absent. Some studies suggest that temporal summation, allodynia, and secondary hyperalgesia may be more pronounced in women than in men. The evidence to support less efficient endogenous pain inhibitory systems in women is mixed and does not necessarily apply to all pain modalities. With regard to psychological factors, depression may not mediate sex differences in pain perception, while the role of anxiety is ambiguous. Cognitive and social factors appear to partly explain some sex‐related differences. Finally, past individual history may be influential in female pain responses. However, these conclusions must be treated with much circumspection for various methodological reasons. Furthermore, some factors/mechanisms remain understudied in the field. There is also a need to assess and improve the ecological validity of findings from laboratory studies on healthy subjects, and perhaps a change of paradigm needs to be considered at this point in time to better understand the factors that influence the experience of women and men who suffer from acute or chronic pain.

Predictors of suicidal ideation in chronic pain patients: An exploratory study

Objectives:To explore whether chronic pain (CP) patients who report suicidal ideation (SI) present a distinctive profile with regard to their sociodemographic characteristics, physical health, psychological well-being, cognitions, and use of antidepressants, illicit drugs, and alcohol for pain relief. Methods:Eighty-eight CP patients completed self-administered questionnaires during their intake assessment at 3 pain clinics located in the province of Québec (Canada). Patients reporting active or passive SI on the Beck Depression Inventory were compared with patients reporting no SI. Between-group univariate analyses were performed using profile variables to compare patients with and without SI. Significant variables were then entered into multiple logistic regression analyses to identify significant independent predictors of SI. Results:Twenty-four percent of patients reported having had SI. Unemployed/disabled patients were 6 times more likely to report SI. Poor sleep quality was the only predictor of SI among the physical variables. For psychological well-being, depressive symptoms did not significantly predict SI. However, the poorer the patients perceived their mental health to be the more likely they were to report SI. Pain-related helplessness was the only predictor for SI among the cognitive variables. Patients who had used illicit drugs as a form of pain relief at any time since pain onset were 5 times more likely to report SI. Similar results were obtained for those who were on antidepressants. Discussion:Some factors associated with SI seem pain specific, whereas others are more generally associated with SI. Better identification and understanding of these factors is essential for the development of targeted suicide prevention programs for at-risk CP patients.

Web-Based Nursing Intervention for Self-Management of Pain After Cardiac Surgery: Pilot Randomized Controlled Trial

Background Most adults undergoing cardiac surgery suffer from moderate to severe pain for up to 6 days after surgery. Individual barriers and attitudes regarding pain and its relief make patients reluctant to report their pain and ask for analgesic medication, which results in inadequate pain management. More innovative educational interventions for postoperative pain relief are needed. We developed a Web-based nursing intervention to influence patient’s involvement in postoperative pain management. The intervention (SOULAGE-TAVIE) includes a preoperative 30-minute Web-based session and 2 brief face-to-face postoperative booster sessions. The Web application generates reflective activities and tailored educational messages according to patients’ beliefs and attitudes. The messages are transmitted through videos of a virtual nurse, animations, stories, and texts. Objective The aim of this single-blinded pilot randomized trial was to investigate the preliminary effects of a virtual nursing intervention (SOULAGE-TAVIE) to improve pain relief in patients undergoing cardiac surgery. Methods Participants (N = 60) were adults scheduled for their first cardiac surgery. They were randomly assigned to the experimental group using SOULAGE-TAVIE (n = 30) or the control group using usual care, including an educational pamphlet and postoperative follow-up (n = 30). Data were collected through questionnaires at the time of admission and from day 1 to day 7 after surgery with the help of a blinded research assistant. Outcomes were pain intensity, pain interference with daily activities, patients’ pain barriers, tendency to catastrophize in face of pain, and analgesic consumption. Results The two groups were comparable at baseline across all demographic measures. Results revealed that patients in the experimental group did not experience less intense pain, but they reported significantly less pain interference when breathing/coughing (P = .04). A severe pain interference with breathing/coughing (pain ranked ≥ 7/10) was reported on day 3 after surgery by 15% of the patients in the experimental group (4/27), as compared to 44% (7/16) in the control group. On day 7 after surgery, participants in the experimental group also exhibited fewer pain-related barriers as measured by the Barriers Questionnaire-II (mean 10.6, SD 8.3) than patients in the control group (mean 15.8, SD 7.3, P = .02). No difference was found for pain catastrophizing. However, in both groups, means revealed a lower tendency to catastrophize pain before surgery as measured by the Pain Catastrophizing Scale (control group mean 1.04, SD 0.74; experimental group mean 1.10, SD 0.95) and after surgery (control group mean score 1.19, SD 0.94; experimental group mean score 1.08, SD 0.99). Finally, the experimental group consumed more opioid medication (mean 31.2 mg, SD 23.2) than the control group (mean 18.8 mg, SD 15.3, P = .001). Conclusions This pilot study provides promising results to support the benefits of this new Web-tailored approach that can increase accessibility to health education and promote pain relief without generating more costs. Trial Registration Clinicaltrials.gov NCT01084018; http://www.clinicaltrials.gov/ct2/show/NCT01084018 (Archived by WebCite® at http://www.webcitation.org/6CoTBkIoT)

The Pittsburgh Sleep Quality Index: Validity and factor structure in young people.

The Pittsburgh Sleep Quality Index (PSQI) is a widely used measure of sleep quality in adolescents, but information regarding its psychometric strengths and weaknesses in this population is limited. In particular, questions remain regarding whether it measures one or two sleep quality domains. The aims of the present study were to (a) adapt the PSQI for use in adolescents and young adults, and (b) evaluate the psychometric properties of the adapted measure in this population. The PSQI was slightly modified to make it more appropriate for use in youth populations and was translated into Spanish for administration to the sample population available to the study investigators. It was then administered with validity criterion measures to a community-based sample of Spanish adolescents and young adults (AYA) between 14 and 24 years old (N = 216). The results indicated that the questionnaire (AYA-PSQI-S) assesses a single factor. The total score evidenced good convergent and divergent validity and moderate reliability (Cronbachs alpha = .72). The AYA-PSQI-S demonstrates adequate psychometric properties for use in clinical trials involving adolescents and young adults. Additional research to further evaluate the reliability and validity of the measure for use in clinical settings is warranted.

Validity of three rating scales for measuring pain intensity in youths with physical disabilities.

There is growing evidence confirming that youths with physical disabilities are at risk for chronic pain. Although many scales for assessing pain intensity exist, it is unclear whether they are all equally suitable for youths. The aim of this study was to address this knowledge gap by comparing the validity of the Numerical Rating Scale (NRS‐11), the Wong Baker FACES Pain Rating Scale (FACES), and a 6‐point categorical Verbal Rating Scale (VRS‐6) for assessing pain intensity among youths (aged 8–20) with physical disabilities.

The Canadian STOP-PAIN project: the burden of chronic pain-does sex really matter?

Objectives:The Canadian STOP-PAIN Project assessed the human and economic burden of chronic pain (CP) in individuals on waitlists of Canadian multidisciplinary pain treatment facilities. This article focuses on sex differences. Objectives were to (1) determine the pain characteristics and related biopsychosocial factors that best differentiated women and men with CP; and (2) examine whether public and private costs associated with CP differed according to sex. Materials and Methods:Sample consisted of 441 women and 287 men who were evaluated using self-administered questionnaires and a structured interview protocol. A subsample (233 women and 137 men) recorded all pain-related expenditures in a comprehensive diary over 3 months. Results:Results revealed that the burden of illness associated with CP was comparable in both sexes for average and worst pain intensity, pain impact on daily living, quality of life, and psychological well-being. The same was true for pain-related costs. The results of a hierarchical logistic regression analysis, in which sex was treated as the dependent variable, showed that factors that differentiated men and women were: work status, certain circumstances surrounding pain onset, present pain intensity, intake of particular types of pain medication, use of certain pain management strategies, pain beliefs, and utilization of particular health care resources. Discussion:This study suggests that women and men who are referred to multidisciplinary pain treatment facilities do not differ significantly in terms of their pain-related experience. However, the aspects that differ may warrant further clinical attention when assessing and managing pain.

Sex differences in psychological response to pain in patients with fibromyalgia syndrome.

Objectives:To examine whether men and women with fibromyalgia syndrome (FMS) differ with respect to pain severity and functioning, pain-related beliefs, or pain-related coping. We hypothesized no significant sex differences in measures of pain and functioning, but that we would observe differences between men and women in how they view and how they cope with FMS-related pain. Methods:A total of 747 women and 48 men with FMS who attended a multidisciplinary treatment program completed the study measures. Analyses of covariance were used to examine sex differences in the study measures, with a P-value of ⩽0.01 and at least a moderate effect size (Cohen d≥0.5) required for a difference to be deemed statistically significant. Results:Men and women did not differ on demographic measures except for their age, with the men in our sample being significantly younger than the women. Consistent with the study hypothesis, the results revealed no sex differences in the measures of pain and functioning. For pain-related beliefs, men were more likely to view pain as reflecting harm, and they were also more likely than women to use activity avoidance as a pain-coping strategy. Discussion:The study findings suggest that women and men with FMS may think about and cope with pain somewhat differently, and may therefore benefit from different types of psychosocial pain intervention.

Assessment of Pain Intensity in Clinical Trials: Individual Ratings vs Composite Scores

OBJECTIVES To evaluate the reliability of findings suggesting that composite scores made up of just two ratings of recalled pain may be adequately reliable and valid for assessing outcome in pain clinical trials. DESIGN Secondary analyses of data from a study where the responsivity of the outcome measures was a critical concern; that is, a study with few subjects testing the effects of a treatment that had only modest effects. Ten adults with spinal cord injury rated four domains of pain intensity (current pain and 24-hour recalled worst, least, and average pain) on four occasions before and after 12 sessions of neurofeedback treatment. We evaluated the reliability and validity of four single ratings and 16 different composite scores. RESULTS None of the single-item scales performed adequately. However, composite scores made up of two items or more yielded consistent effect size estimates. CONCLUSIONS The findings provide additional evidence that two-item composite scores may be adequate for assessing the primary outcome of pain intensity in chronic pain clinical trials. Additional research is needed to further establish the generalizability of these findings.

Cognitive Fusion and Pain Experience in Young People

Objectives:Acceptance and Commitment Therapy (ACT) has been shown to be an effective treatment for chronic pain in young people. Cognitive fusion is a key concept of ACT that is hypothesized to contribute to distress and suffering. In this study, we sought to: (1) test hypothesized associations between cognitive fusion and pain intensity, disability, and catastrophizing; and (2) examine the function of cognitive fusion as a possible mediator between catastrophizing and disability. Methods:A community sample of 281 young people (11 to 20 y) completed measures assessing cognitive fusion, pain intensity, disability, and pain catastrophizing. Results:Cognitive fusion was positively related to pain intensity (r=0.24, P<0.01), disability (r=0.32, P<0.001), and pain catastrophizing (r=0.47, P<0.001). Moreover, cognitive fusion was found to mediate the association between pain catastrophizing and disability (&bgr;=0.01, 95% confidence interval=0.002-0.024, 5000 bootstrap resamples). Discussion:The findings indicate that cognitive fusion is moderately to strongly associated with pain-related outcomes, which support the need for further research to (1) better understand the relationship between cognitive fusion and adjustment to chronic pain, and (2) determine whether the benefits of treatments such as ACT are mediated, at least in part, by reductions in cognitive fusion.