Subgroups of Pediatric Patients With Functional Abdominal Pain: Replication, Parental Characteristics, and Health Service Use

A developmental framework for understanding the influence of sex and gender on health: Pediatric pain as an exemplar

Sex differences are a robust finding in many areas of adult health, including cardiovascular disease, psychiatric disorders, and chronic pain. However, many sex differences are not consistently observed until after the onset of puberty. This has led to the hypothesis that hormones are primary contributors to sex differences in health outcomes, largely ignoring the relative contributions of early developmental influences, emerging psychosocial factors, gender, and the interaction between these variables. In this paper, we argue that a comprehensive understanding of sex and gender contributions to health outcomes should start as early as conception and take an iterative biopsychosocial-developmental perspective that considers intersecting social positions. We present a conceptual framework, informed by a review of the literature in basic, clinical, and social science that captures how critical developmental stages for both sex and gender can affect children's health and longer-term outcomes. The literature on pediatric chronic pain is used as a worked example of how the framework can be applied to understanding different chronic conditions.

A systematic review of the biopsychosocial dimensions affected by chronic pain in children and adolescents: identifying reliable and valid pediatric multidimensional chronic pain assessment tools

Pediatric chronic pain is a complex experience that is often challenging to describe and measure. Multidimensional tools that evaluate the biopsychosocial impact of chronic pain in pediatric patients can help clinicians to prioritize and tailor interdisciplinary pain care; yet, the psychometric value and clinical utility of such tools has not yet been systematically studied in the literature. The purpose of this review was to identify multidimensional biopsychosocial tools used in pediatric chronic pain, synthesize their reliability and validity evidence, and draw on this evidence to describe the relationships between chronic pain and biopsychosocial domains. The search involved 2 phases to (1) identify eligible tools and (2) conduct a measured forward citation search of tool development articles. Tool eligibility was guided by the Multidimensional Biobehavioral Model of Pediatric Pain and study eligibility was focused on primary chronic pain diagnoses unrelated to disease. Data extraction was focused on reliability and validity evidence of eligible tools, guided by the Standards for Educational and Psychological Testing. Results yielded 6 tools that included 64 eligible studies, highlighting 84 significant relationships between pain and functional interference across 11 biopsychosocial variables. All tools were shown to have good internal consistency and evidence of validity, primarily through relationships to other variables. Of the 6 tools, the most brief and easy to use were the most under studied. Further psychometric research is warranted for these tools to investigate their clinical utility and psychometric properties in guiding and prioritizing pain care for children and adolescents.

Phenotyping Chronic Musculoskeletal Pain in Male and Female Adolescents: Psychosocial Profiles, Somatosensory Profiles and Pain Modulatory Profiles

Purpose

A major limitation in treatment outcomes for chronic pain is the heterogeneity of the population. Therefore, a personalized approach to the assessment and treatment of children and adolescents with chronic pain conditions is needed. The objective of the study was to subgroup pediatric patients with chronic MSK pain that will be phenotypically different from each other based on their psychosocial profile, somatosensory function, and pain modulation.

Patients and Methods

This observational cohort study recruited 302 adolescents (10–18 years) with chronic musculoskeletal pain and 80 age-matched controls. After validated self-report questionnaires on psychosocial factors were completed, quantitative sensory tests (QST) and conditioned pain modulation (CPM) were performed.

Results

Three psychosocial subgroups were identified: adaptive pain (n=125), high pain dysfunctional (n=115), high somatic symptoms (n=62). Based on QST, four somatosensory profiles were observed: normal QST (n=155), thermal hyperalgesia (n=98), mechanical hyperalgesia (n=34) and sensory loss (n=15). Based on CPM and temporal summation of pain (TSP), four distinct groups were formed, dysfunctional central processing group (n=27) had suboptimal CPM and present TSP, dysfunctional inhibition group (n=136) had suboptimal CPM and absent TSP, facilitation group (n=18) had optimal CPM and present TSP, and functional central processing (n=112) had optimal CPM and absent TSP. A significant association between the psychosocial and somatosensory profiles. However, no association was observed between the psychosocial or somatosensory profiles and pain modulatory profiles.

Conclusion

Our results provide evidence that adolescents with chronic musculoskeletal pain are a heterogenous population comprising subgroups that may reflect distinct mechanisms and may benefit from different treatment approaches. The combination of screening self-reported questionnaires, QST, and CPM facilitate subgrouping of adolescents with chronic MSK pain in the clinical context and may ultimately contribute to personalized therapy.

Internet-delivered cognitive behavioral therapy for youth with functional abdominal pain: a randomized clinical trial testing differential efficacy by patient subgroup

ABSTRACT

Inconsistent results of psychological treatments for pediatric functional abdominal pain (FAP) may be due to heterogeneity of patients' pain-related psychological characteristics. This randomized controlled trial tested whether statistically derived patient subgroups (high pain dysfunctional [HPD], high pain adaptive [HPA], and low pain adaptive [LPA]) moderated response to cognitive behavior therapy (CBT) for adolescents with FAP and their parents (n = 278 dyads; patients were 66% female, mean [SD] age was 14.62 [1.88] years, and parents were 95% female). Randomization to Internet-delivered CBT vs Internet-delivered pain education (EDU) was stratified by patient subgroup. Follow-up assessments of gastrointestinal (GI) symptoms (primary outcome), abdominal pain, and pain interference were at midtreatment, posttreatment, 6 months, and 12 months. Data were analysed using linear mixed effects models. Significant treatment × subgroup × time interaction effects showed that patient subgroup significantly moderated the effect of treatment on GI symptoms (t[853 = -2.93, P = 0.003) and abdominal pain (t(844) = -2.14, P = 0.03) across the treatment period. Among HPD youth, those in CBT had significantly greater GI symptom reduction than those in EDU through posttreatment. By contrast, among HPA and LPA youth, symptom improvement did not differ by treatment condition. Furthermore, among all patients assigned to CBT, HPD youth demonstrated significantly greater reductions in GI symptoms compared with HPA and LPA youth and greater reductions in abdominal pain compared with LPA youth. All subgroups maintained symptom reductions throughout the follow-up period. Results suggest that subgrouping FAP patients may inform treatment allocation and optimize treatment response.

Place and Pain: Association Between Neighborhood SES and Quantitative Sensory Testing Responses in Youth With Functional Abdominal Pain

OBJECTIVE

Neighborhood socioeconomic status (SES) is linked to self-reported pain severity and disability but its association with evoked pain responsiveness in individuals with chronic pain remains unclear. The present study examined relations between neighborhood SES, assessed through the area deprivation index (ADI), and static and dynamic pain response indices. It was hypothesized that youth with functional abdominal pain (FAP) living in lower SES neighborhoods would exhibit lower pain threshold, lower pain tolerance, and reduced conditioned pain modulation (CPM) compared to youth living in higher SES neighborhoods.

METHODS

Participants were 183 youth with FAP and their parents. Youth completed a quantitative sensory testing protocol. Family addresses were used to compute ADI scores. Thermal stimuli for pain threshold and tolerance were delivered to participants' forearms using thermodes. CPM, an index of descending pain inhibition, was determined using a thermode as test stimulus and a hot water bath as conditioning stimulus.

RESULTS

As hypothesized, youth with FAP living in lower SES neighborhoods exhibited weaker CPM. Contrary to hypotheses, lower neighborhood SES was associated with neither pain thresholds nor with pain tolerance.

CONCLUSIONS

These findings demonstrated the independent contribution of place of residence-an often neglected component of the biopsychosocial model-to efficiency of descending pain inhibition. Understanding the mechanisms that account for such associations between place and pain could guide the development of public health and policy initiatives designed to mitigate chronic pain risk in underserved and economically marginalized communities.

Elevated fecal calprotectin is linked to psychosocial complexity in pediatric functional abdominal pain disorders

Objective

Children with functional abdominal pain disorders (FAPD) and clinical elevations in three risk areas (anxiety, functional disability, and pain) have been found to be at increased risk for persistent disability. We evaluated if the presence of these three risk factors corresponded with greater gastrointestinal inflammation (measured via fecal calprotectin; FC) compared to those with no risk factors. FC concentration differences between children with three risk factors and those with one and two risk factors were explored.

Results

Fifty-six children with FAPD (M_age = 12.23) completed measures of anxiety (Screen for Child Anxiety Related Disorders), disability (Functional Disability Inventory), and pain intensity (Numeric Rating Scale). Participants were stratified into risk groups (range: 0–3). Fisher’s exact tests were conducted to determine if children with three versus fewer risk factors were more likely to have elevated FC (≥ 50 µg/g) versus normal levels. Children with three risk factors (M_FC = 86.04) were more likely to have elevated FC compared to children with zero (M_FC = 25.78), one (M_FC = 38.59), and two risk factors (M_FC = 45.06; p’s < 0.05). Those with three risk factors had borderline elevated FC concentrations whereas those with fewer had normal FC concentrations. Findings suggest the importance of a biopsychosocial approach to help elucidate a FAPD phenotype.

Does Quantitative Sensory Testing Improve Prediction of Chronic Pain Trajectories? A Longitudinal Study of Youth With Functional Abdominal Pain Participating in a Randomized Controlled Trial of Cognitive Behavioral Treatment

OBJECTIVES

Youth with functional abdominal pain (FAP) experience significant pain-related distress and functional impairment. Although quantitative sensory testing protocols have identified alterations in pain modulatory systems that distinguish youth with FAP from healthy controls, the extent to which evoked pain responses predict subsequent trajectories of pain symptoms and disability over and above established psychosocial risk factors is unclear.

METHODS

The present study included 183 adolescents with FAP who were enrolled in a randomized controlled trial comparing an 8-week, internet-delivered program of cognitive behavior therapy (n=90) or pain education (n=93). Participants completed a quantitative sensory testing protocol before the intervention and were followed for 12-month posttreatment.

RESULTS

Whereas adolescents with FAP who exhibited stronger baseline conditioned pain modulation (CPM) reported decreases in pain-related interference over follow-up (b=-0.858, SE=0.396, P=0.032), those with weaker CPM exhibited high, relatively stable levels of pain-related interference over time (b=-0.642, SE=0.400, P=0.110). CPM status predicted changes in pain-related interference after controlling for the effects of treatment condition and psychosocial risk factors. Static measures of pain sensitivity (ie, pain threshold, pain tolerance) and temporal summation of second pain were not associated with changes in measures of abdominal pain, gastrointestinal symptom severity, or pain-related interference over follow-up.

DISCUSSION

The present findings contribute to a growing literature on the predictive utility of quantitative sensory testing indices and suggest that CPM may complement existing psychosocial risk measures in determining individualized pain-related risk profiles.