No moderating impact of a medically unexplained etiology on the relationship between psychological profile and chronic pain

Stressful life events and low back pain in older men: A cross-sectional and prospective analysis using data from the MrOS study

BACKGROUND

Stressful life events, such as loss of a partner, loss of a pet or financial problems, are more common with increasing age and may impact the experience of pain. The aim of the current study is to determine the cross-sectional and prospective association between stressful life events and low back pain reporting in the Osteoporotic Fracture in Men Study, a cohort of older men aged ≥65 years.

METHODS

At a study visit (March 2005-May 2006), 5149 men reported whether they had experienced a stressful life event or low back pain in the prior 12 months. Following that visit, data on low back pain patients were gathered through triannual questionnaires every 4 months for 1 year. Multivariable logistic regression analyses estimated the association of stressful life events with recent past low back pain or future low back pain.

RESULTS

N = 2930, (57%) men reported at least one stressful life event. The presence of a stressful life event was associated with greater odds of any low back pain (OR = 1.42 [1.26-1.59]) and activity-limiting low back pain (OR = 1.74 [1.50-2.01]) in the same period and of any low back pain (OR = 1.56 [1.39-1.74]) and frequent low back pain (OR = 1.80 [1.55-2.08]) in the following year.

CONCLUSION

In this cohort of men, the presence of stressful life events increased the likelihood of reporting past and future low back pain.

SIGNIFICANCE

Stressful life events such as accident or illness to a partner are common in later life and may impact the experience of pain. We present cross-sectional and prospective data highlighting a consistent association between stressful life events and low back pain in older men. Further, there is evidence to suggest that this relationship is upregulated by an individual's living situation. This information may be used to strengthen a biopsychosocial perspective of an individual's pain experience.

Illness perceptions and illness behaviours in back pain: A cross-sectional cluster analysis

BACKGROUND

Individuals' perceptions of back pain may shape what they do in response to manage their pain, for example, self-care, medication and seeking healthcare. Illness perceptions encompass a variety of beliefs such as how long pain is expected to last and whether treatments are perceived to control pain. Whether these beliefs meaningfully cluster and whether these clusters are associated with how people manage their back pain are currently unknown.

METHODS

1,343 individuals with back pain from a general population sample completed the brief Illness Perceptions Questionnaire and measures about their pain and illness behaviours. Using a two-stage cluster analysis, we identified four distinct clusters of individuals. Logistic regression was used to investigate relationships between cluster membership and illness behaviours.

RESULTS

After adjustment for socio-demographic characteristics, pain severity, interference and duration, relative to a low threat illness perception cluster, a high threat cluster was more likely to have contacted a general practitioner (OR: 3.03, 95% CI: 1.75, 5.23) and a moderate threat-high treatment control cluster was more likely to have consulted a physical therapist (OR: 2.21, 95% CI: 1.26, 3.87). Both the moderate threat-high treatment control cluster and high threat cluster were also less likely to have reported self-care (OR: 0.64, 95% CI: 0.43, 0.95; OR: 0.53, 95% CI: 0.34, 0.83, respectively).

CONCLUSIONS

The cluster analysis provided a meaningful classification of individuals based on their cognitive illness perceptions of their back pain, as these clusters were associated with different illness behaviours. Interventions which modify clusters of illness perceptions may be effective in influencing how individuals respond to back pain.

SIGNIFICANCE

Within a general population setting, we identified four clearly distinct groups of people based on the perceptions they held about their back pain. These groupings seemed to reflect meaningful characterisations as they differed based on the characteristics of their pain (e.g., severity and duration) and, after adjustment for these characteristics, were associated with different ways of managing pain. Interventions which focus on targeting the sets of illness perceptions that people hold may be effective in influencing how individuals manage back pain.

Establishing Central Sensitization-Related Symptom Severity Subgroups: A Multicountry Study Using the Central Sensitization Inventory

OBJECTIVES

The goal of this study was to identify central sensitization-related symptom severity subgroups in a large multicountry sample composed of patients with chronic pain and pain-free individuals using the Central Sensitization Inventory (CSI).

METHODS

A large, pooled international (N = 8 countries) sample of chronic pain patients plus healthy subjects (total N = 2,620) was randomly divided into two subsamples for cross-validation purposes. First, a hierarchical cluster analysis (HCA) was performed using CSI item-level data as clustering variables (test sample; N = 1,312). Second, a latent profile analysis (LPA) was conducted to confirm the optimal number of CSI clusters (validation sample; N = 1,308). Finally, to promote implementation in real-world clinical practice, we built a free online Central Sensitization Inventory Symptom Severity Calculator.

RESULTS

In both HCA (N = 1,219 valid cases) and LPA (N = 1,245 valid cases) analyses, a three-cluster and three-profile solution, respectively, emerged as the most statistically optimal and clinically meaningful. Clusters were labeled as follows: (i) Low Level of CS-Related Symptom Severity, (ii) Medium Level of CS-Related Symptom Severity, and (iii) High Level of CS-Related Symptom Severity.

CONCLUSIONS

Our results indicated that a three-cluster solution clearly captured the heterogeneity of the CSI data. The calculator might provide an efficient way of classifying subjects into the cluster groups. Future studies should analyze the extent to which the CSI cluster classification correlates with other patient-reported and objective signs and symptoms of CS in patients with chronic pain, their associations with clinical outcomes, health-related costs, biomarkers, (etc.), and responsiveness to treatment.

Patient's perceptions of physical examination in the setting of chronic pain

INTRODUCTION

Despite its clinical utility, progressive reliance on imaging technology can lead to devaluing the physical examination in patients with chronic pain. The primary objective of this study was to determine whether chronic pain patients have a positive or negative perception of the physical examination.

METHODS

After institutional ethics committee approval, 120 adult patients as a convenience sample who attended a chronic pain clinic were included. Participants completed a 10-item survey regarding their overall perception of the physical examination. Kruskal-Wallis and Mann-Whitney U test analyses were conducted to explore associations between test items and patient ages, gender, employment, pain diagnosis, and duration of pain. All cross-tabulations of categorical variables were analyzed using Fisher's exact test for associations.

RESULTS

The majority of participants were male (51%), aged 50-70 (44%). The most common pain diagnosis was back pain (62%). Most patients (77%) indicated that the overall experience of being examined was highly positive. Patients believe in the value of the physical examination as a diagnostic tool (97%). Patients believe in the relational value of the physical examination (92%). Age, gender, employment, pain diagnosis, and duration of pain were not associated with a more positive perception of the physical examination.

CONCLUSION

Patients with chronic pain indicate that the physical examination is a highly positive aspect of their care. There are some negative aspects of been examined which physicians should be aware of. This study adds to our knowledge regarding the physical exam in chronic pain patients. It will inform practice and training.

Whether chronic pain is medically explained or not does not moderate the response to cognitive-behavioural therapy

OBJECTIVES

To determine whether pain-related treatment outcomes, following an online Cognitive Behavioural Therapy (CBT) intervention for chronic pain, were moderated by the pain etiology of a medically explained or unexplained origin.

METHODS

Data were available from 471 participants who completed the online pain management program between March 2013 and August 2014. Participants' pain symptoms were classified as being medically explained symptoms (MES: n = 292) or medically unexplained symptoms (MUS: n = 222) via analysis of clinical data. Outcome variables were pain-related disability, average pain intensity, depression and anxiety.

RESULTS

Moderation analyses were non-significant for all dependent variables. Between group differences (CBT and control) were larger for depression in those classified with MES, compared with MUS (MUS: mean change = -3.50 [95% CI = -4.98 to -2.22]; MES: mean change = -5.72 [95% CI = -7.49 to -4.09]). However, between group differences were small for pain intensity (MUS: mean change = -0.03 [95% CI = -0.83 to 0.81]; MES: mean difference = -1.12 [95% CI = -1.84 to 0.40]).

CONCLUSION

The therapeutic outcomes examined in this study associated with an online CBT program do not appear to be altered by whether the participants' pain symptoms are medically explained or unexplained.