Article ID: 25-00031
Chronic pain patients can achieve substantial improvement within six months, but some require prolonged care. This study aimed to explore differences in baseline characteristics and questionnaire responses between patients who showed significant improvement within six months (completion group) and those requiring treatment beyond six months (continuation group). A cross-sectional study was conducted among 131 patients. Patients were classified into completion group (n = 97) or continuation group (n = 34). Baseline data included demographic information (sex, age), ICD-11J classification, average pain intensity using the numeric rating scale (NRS) and scores from the Brief Pain Inventory (BPI), Pain Catastrophizing Scale (PCS), Pain Disability Assessment Scale (PDAS), Hospital Anxiety and Depression Scale (HADS), Pain Self-Efficacy Questionnaire (PSEQ), EuroQol Five Dimensions Questionnaire (EQ-5D), and Athens Insomnia Scale (AIS). There were no significant differences in age, sex, or ICD-11J classification between the groups. However, the continuation group exhibited significantly higher baseline scores for average pain intensity, PDAS, and HADS depression than the completion group. Patients with higher baseline pain intensity, greater functional impairment, and more severe depressive symptoms were more likely to require extended multidisciplinary treatment. Early identification of these risk factors is critical for optimizing treatment planning and improving outcomes in chronic pain management.
Effective chronic pain management aims to alleviate pain, but complete pain relief is often unattainable. Pain reduction is a critical component of chronic pain management, but it is not considered the primary objective1-2). Instead, the overarching goal of treatment is to enhance patients’ functional capabilities, enabling them to engage in activities of personal value despite the persistence of some degree of pain. This approach ultimately contributes to improving the quality of life (QOL) for individuals living with chronic pain.
At the Pain Management Center of Hoshi General Hospital, we deliver a multidisciplinary approach to pain treatment, incorporating patient education, cognitive behavioral therapy (CBT)-based exercise therapy, psychotherapy, and pharmacotherapy. The specific details of these interventions, including the CBT-based frameworks employed in education, exercise, and psychotherapy, have been described in previous studies3-4). The primary objective of patient education within this framework is to facilitate a return to functional daily living by fostering the acquisition of adaptive daily habits and effective pain-coping strategies5). Outpatient treatment is typically planned for a duration of six months, with the treatment course developed collaboratively through multidisciplinary conferences. This treatment duration was set because most of the literature6) rarely includes follow-up periods longer than six months. Some patients successfully complete their treatment within this period, but others require extended care. This variability underscores the need to identify factors contributing to prolonged treatment durations.
We hypothesized that specific patient characteristics at initial examination, including the intensity of pain and psychosocial factors associated with pain, may influence the extended duration of multidisciplinary pain management. However, the precise determinants of prolonged treatment remain unclear. Elucidating these factors is crucial for clinicians, patients, and researchers to refine treatment planning and optimize care strategies for individuals undergoing multidisciplinary pain management.
The purpose of this study was to examine differences between two patient groups in baseline questionnaire information collected upon initial examination:the completion group, consisting of individuals who recovered or achieved significant improvement within six months, and the continuation group, consisting of patients requiring treatment for more than six months. By identifying key differences at initial examination between these groups, we aimed to gain insights into factors influencing treatment duration and inform evidence-based strategies for improving chronic pain management.
The sample size calculation for this study was conducted using G*Power 3.1 software (Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany). Chronic pain is estimated to affect 20-23 million individuals in Japan. Based on an effect size of 0.3, an alpha level of 0.05, and a statistical power (1-β error probability) of 0.95, power analysis determined that a minimum of 111 participants would be required to achieve sufficient statistical power for this study.
2. ParticipantsThe cross-sectional study included 131 patients (47 men and 84 women) who were treated on an outpatient basis and also provided complete responses to a self-administered questionnaire at their initial visit and six months after starting multidisciplinary pain treatment at the Pain Management Center, between April 2015 and May 2023. Participants were categorized into two groups:the completion group (n = 97;34 men and 63 women) and the continuation group (n = 34;13 men and 21 women). Members of the completion group were patients discharged within six months because their multidisciplinary pain management was effective. The continuation group included patients who required ongoing treatment beyond six months due to persistent symptoms and/or lack of improvement in QOL. A total of 351 patients were initially assessed but 220 were excluded from analysis because they discontinued treatment. Ultimately, the study analyzed data from the 131 patients who maintained uninterrupted treatment, as illustrated in the study flowchart (Fig. 1).
Outpatient Multidisciplinary Treatment ProgramThe outpatient treatment program integrates exercise therapy, psychotherapy, and patient education, and is designed to span a six-month period. This includes an additional month beyond the 150-day rehabilitation period approved by Japan’s national insurance system. All patients who participated in the study received exercise therapy, pharmacotherapy, and psychological interventions as part of multidisciplinary pain treatment.
The program’s specific components are:
1. Exercise Therapy:This component includes physical fitness and individualized training provided by physical therapists. The program involves aerobic exercises such as walking and underwater exercise, as well as muscle strengthening and stretching activities. Trunk flexor muscles were strengthened through sit-up exercises, and trunk extensor muscles were targeted with extension exercises. Each exercise session lasted 20-40 minutes and was conducted once every one to four weeks, depending on the patient. To minimize variability among patients, self-training guidance was provided for periods when therapy sessions were not scheduled.
2. Psychological Assessment and Counseling: A certified public psychologist conducted pain-related psychological interviews to evaluate patients’ thoughts, attitudes, and perceptions of pain. These interviews also assessed the nature of the pain and contributed to the development of tailored treatment plans. Counseling sessions were limited to chronic pain patients requiring psychological support and each lasted for 60 minutes. In the completion group, counseling sessions conducted by certified psychologists were provided to 51 of 97 patients (18 men and 33 women;52.6%). In the continuation group, counseling sessions were provided to 19 of 34 patients (8 men and 11 women;55.9%).
3. Patient Education:Delivered by a multidisciplinary team of specialists, patient education sessions covered various topics. These included pain mechanisms (orthopedic surgeon), exercise and pacing (physical therapist), assertiveness and relaxation training (psychologist), and daily life habits associated with nutrition (nutritionist). Nutritional guidance was generally provided once during the initial session by a registered nutritionist. The guidance utilized results from the InBody® body composition analyzer, including body mass index (BMI), muscle mass, and fat mass, obtained at the initial hospital visit. However, these measurements were only performed at the initial visit (baseline) and were not routinely repeated at the end of treatment. Education sessions were conducted on an outpatient basis and lasted up to 30 minutes per session. A unique feature of the program was the inclusion of family members or significant others in selected educational sessions and psychological interviews to provide comprehensive support5).
Program Goals and EvaluationThe primary objective of the outpatient treatment program was to assist patients in resuming functional daily activities by fostering the development of adaptive habits and effective pain-coping strategies. Treatment efficacy was defined based on the extent of improvement in pain levels and functional capacity. Treatment was deemed effective if patients exhibited sustained improvements or stability in pain levels six months post-treatment compared with baseline. Complete pain relief was not an anticipated outcome, and patient education emphasized the importance of improving sleep, nutrition, exercise habits, and stress management. Patients were encouraged to maintain these improvements and adhere to the guidance provided by the clinic after completing the program.
Inclusion and Exclusion CriteriaInclusion criteria for the study were as follows:1) individuals unable to work or attend school because of chronic musculoskeletal pain;2) those confined to their homes in daily life but expressing a desire to return to work or school;3) individuals who agreed to the treatment protocol;and 4) those capable of covering the associated treatment expenses. Exclusion criteria included:1) patients unable to participate in the treatment regimen and 2) older adults with dementia or cognitive impairments preventing them from completing the required questionnaires3,4). 3) Patients undergoing combination therapy, including treatment for underlying conditions such as malignant tumors or other obvious organic abnormalities, as well as pharmacological treatments such as opioids for pain management. Chronic pain diagnoses were established by orthopedic surgeons during the initial clinical evaluation at the Pain Management Center. Chronic pain was defined according to the International Association for the Study of Pain (IASP) as “pain that persists or recurs for more than three months.”
3. Evaluation of pain and associated factorsPatients with chronic pain were systematically evaluated before their participation in our outpatient multidisciplinary treatment management program. Data collection focused on patient demographics, specifically age, pain intensity quantified using the NRS numeric rating scale7), and pain severity, which was quantified using the Brief Pain Inventory (BPI)8). Psychosocial factors related to pain were assessed using validated instruments: the Pain Catastrophizing Scale (PCS), which measures rumination, magnification, and helplessness9,10);the Pain Disability Assessment Scale (PDAS)11);the Hospital Anxiety and Depression Scale (HADS)12,13);the Pain Self-Efficacy Questionnaire (PSEQ)14,15);and the Athens Insomnia Scale (AIS)16). QOL was evaluated using the EuroQol Five Dimensions Questionnaire (EQ-5D)17,18). All these scales, including the PCS10), PDAS11), HADS13), PSEQ15), AIS16), and EQ-5D18), have been validated in Japan by previous studies. The multidisciplinary team conducting the evaluations consisted of nine healthcare professionals, including eight specialists (an orthopedic surgeon, a psychiatrist, a nurse, a physical therapist, an occupational therapist, a clinical psychologist, a pharmacist, and a nutritionist) who were responsible for data collection, and a technician who conducted data analyses. All data were obtained during each patient’s initial visit, then after 3 and 6 months of treatment to ensure consistency and standardization.
4. Statistical analysesThe severity of chronic pain, pain-related psychosocial factors, and quality-of-life (QOL) outcomes were assessed at three time points:the initial visit, and three months and six months post-enrollment, using self-administered questionnaires. Data normality was evaluated using the Shapiro-Wilk test before further statistical analysis. To examine the characteristics of chronic pain patients, comparisons between the completion group and the continuation group were conducted based on age, gender, and ICD-11J classification. Differences in categorical variables, including sex and ICD-11J classification, were analyzed using chi-square tests, and differences in continuous variables, such as age, were assessed using unpaired t-tests. Further analyses were performed to compare assessment outcomes between the completion and continuation groups. For these comparisons, unpaired t-tests were applied to evaluate differences in individual questionnaire scores. Statistical analyses were performed using chi-square tests as a multiple comparison method with Bonferroni correction because the sample size was slightly small. Statistical significance was set at a p value of less than 0.05. All statistical analyses used IBM SPSS Statistics for Windows, version 25.0 (IBM Corp., Armonk, NY, USA).
Flowchart of patients classified in or excluded from our study
The sample for this cross-sectional study was drawn from 131 patients who fully completed a self-administered questionnaire during their initial visit to our Pain Management Center between April 2015 and May 2023. Initially, 351 patients with chronic pain provided valid questionnaire responses at their initial examination; however, 220 were subsequently excluded because of disqualifying dropouts during their treatment period.
The Shapiro-Wilk test confirmed that all data conformed to a normal distribution, permitting the use of parametric testing, and t-tests were therefore used. Table 1 summarizes the descriptive statistics, unpaired t-test results for age differences, and chi-square test results for sex differences between the completion and continuation groups. No statistically significant differences were observed in age or gender between the two groups.
Table 2 provides a cross-tabulation of the two groups by ICD-11J classification. Chi-square tests were conducted across various classifications, including major diagnostic categories, specific disease names, primary diagnoses, K-factors, and S-factors. However, none of these analyses found statistically significant differences. Also, there were no statistically significant difference in chi-square tests with Bonferroni correction.
Further analysis of baseline evaluation data revealed notable differences between the two groups in key metrics. Patients in the continuation group had significantly higher scores for average pain (NRS, p = 0.043), functional disability (PDAS, p = 0.012), and depressive symptoms (HADS depression, p = 0.011), as shown in Table 3.
This study identified significant differences in clinical outcomes between the completion group and the continuation group, specifically in average pain intensity (NRS), PDAS, and HADS depression scores. Patients in the continuation group showed significantly higher values for these measures than those in the completion group. These findings suggest that individuals presenting with higher levels of pain, greater impairment in daily functioning due to pain, and elevated depressive symptoms at their initial consultation are more likely to require prolonged treatment. The pathophysiology of chronic pain is multifaceted, involving an intricate interplay of biological and psychosocial components. In cases of prolonged musculoskeletal pain in particular, the causal relationships between pain and its associated factors become increasingly ambiguous. Pain behaviors and psychosocial factors also often become more intertwined as pain persists, reflecting the evolving complexity of chronic pain syndromes19).
The IASP underscores the multifaceted nature of chronic pain management, in support of an interdisciplinary approach. Recommended strategies include reducing, tapering or discontinuing ineffective medications;incorporating physical therapy and psychological interventions;implementing lifestyle modifications such as maintaining a healthy diet, weight management, and sleep hygiene;and exploring complementary therapies such as acupuncture and mind-body techniques. Effective treatment plans are typically individualized, integrating multiple modalities tailored to the individual’s specific condition, overall health status, and personal circumstances. The primary objectives are often to reduce pain and, more importantly, to enhance functional ability, rather than to achieve complete pain resolution19). Chronic pain extends beyond a persistent physical sensation;it is a complex and debilitating condition that can substantially impair an individual’s capacity for daily activities, occupational responsibilities, and social engagement. The subjective nature of chronic pain, characterized by significant variability in its intensity and impact among individuals, underscores the necessity of personalized therapeutic approaches. To support both clinicians and patients in addressing this pervasive condition, the IASP provides a comprehensive array of resources, including educational factsheets, webinars, journal articles, and tools tailored to those living with chronic pain19).
Previous studies have provided limited insights into the factors predicting treatment outcomes in multidisciplinary pain management. Castelnuovo et al.20) highlighted several psychosocial factors influencing treatment efficacy, suggesting their potential role as predictors of outcomes. Their findings emphasize that psychological variables such as anxiety, depression, pain catastrophizing, and self-efficacy, as well as coping strategies, significantly affect treatment effectiveness. The study found that in various neurological conditions, these psychological factors can serve as risk factors, modulate pain experiences, or affect therapeutic outcomes. They further underscored the importance of considering both universal psychological factors, including depression, anxiety, and pain catastrophizing, and condition-specific factors. For example, chronic musculoskeletal pain is frequently associated with avoidance behaviors, anger, uncertainty about the future, and a history of childhood trauma, whereas chronic headaches are influenced by emotional and cognitive components. In certain cases, coping strategies traditionally regarded as maladaptive, such as activity avoidance, may exhibit adaptive qualities. Neuropathic pain, particularly when accompanied by allodynia, shows a close association between psychosocial factors and pain intensity, with fear and discomfort playing prominent roles. Pain arising from severely disabling conditions is significantly associated with psychological factors, especially pain catastrophizing, with its effects modulated by perceived social support and employed coping strategies. Emotional factors, such as depression, anxiety, and anger, alongside cognitive aspects like self-efficacy, affect treatment outcomes. Holistic approaches addressing the individual’s broader life context and their interactions with caregivers and family have been shown to enhance treatment effectiveness. Depression, in particular, is a predictive factor for pain in neurological conditions.
In another study, Hayashi et al.21) classified patients with chronic low back pain undergoing multidisciplinary treatment into good-outcome and poor-outcome groups to examine predictors of treatment success. They reported that the good-outcome group showed significantly lower scores on pain intensity (as measured by the Visual Analogue Scale [VAS]), the PDAS, and the emotional subscale of the McGill Pain Questionnaire. They also demonstrated fewer non-organic pain descriptors and shorter pain durations than the poor-outcome group.
These findings collectively underscore the critical role of psychosocial factors in influencing prolonged treatment durations and outcomes, providing valuable insights for healthcare professionals employing multidisciplinary approaches to pain management. This preliminary study revealed associations between extended treatment durations and variables such as pain intensity, pain-related disability, and depression in chronic pain patients. Consequently, addressing these multifaceted factors within a multidisciplinary framework is deemed essential for optimizing treatment outcomes. As previously mentioned, psychosocial factors play a crucial role in the management of chronic pain. Active participation and cooperation of family members can enhance treatment outcomes by promoting patients’ understanding of their pain and supporting their daily lives. In our multidisciplinary pain treatment program, we therefore involve not only the patients themselves but also their families as an integral part of the treatment process.
Given the limited research examining treatment durations within multidisciplinary pain management, our research offers meaningful contributions. The findings suggest that pre-treatment assessments of pain severity, disability levels, and depression may provide valuable indicators for predicting treatment duration.
However, the study also has several important limitations. First, there is potential for selection bias, because the sample was restricted to chronic pain patients who fully completed questionnaires. Second, the study did not evaluate detailed characteristics and duration of pain. Future research should address these limitations by broadening the scope of patient inclusion criteria and incorporating detailed pain classification systems. Future studies may also consider refining the assessment process by simplifying questionnaires to streamline data collection. Further studies are warranted to evaluate the confounding effects of psychosocial factors on treatment duration following multidisciplinary pain treatment interventions. Identifying and mitigating these confounders will be essential for improving the precision and efficacy of pain management strategies.
In conclusion, this exploratory study suggests that chronic pain patients with high initial pain severity, significant pain-related daily life impairment, and depressive symptoms are more likely to require prolonged multidisciplinary pain treatment. These findings underscore the importance of integrating comprehensive psychosocial assessments into pre-treatment evaluations to predict and manage extended treatment durations effectively.
Descriptive statistics, chi-square test results for age comparisons, and unpaired t-test results for gender comparisons
1)Age comparisons used the unpaired t-test.
2)Sex comparisons used the chi-square test with Bonferroni correction.
Age values are presented as mean (standard deviation).
A cross tabulation of the two groups and relevant ICD-11J classifications
p = 0.7531)
1) ICD-11J classification comparisons used the chi-square test with Bonferroni correction.
Descriptive statistics of initial examination for the completion group and the continuation group
Unpaired t-tests were performed to compare assessment outcomes between the completion and continuation groups.
Abbreviations:SD, standard deviation;QOL, quality of life;NRS, numeric rating scale [for pain intensity];BPI, Brief Pain Inventory;PCS, Pain Catastrophizing Scale;PDAS, Pain Disability Assessment Scale;HADS, Hospital Anxiety and Depression Scale;PSEQ, Pain Self-Efficacy Questionnaire;EQ-5D, EuroQol Five Dimensions Questionnaire;AIS, Athens Insomnia Scale.
Bold font indicates statistical significance.
The authors are grateful to the clinical staff who supported this research:Yusaku Fukada, Ko Matsudaira, Satoshi Kasahara, Akira Onda, Yukie Moto, Akira Furuichi, Kenji Nihei, Takuma Sanpei, Yusaku Sarara, Katsuki Nojima, Shun Satoh, Sawako Tani, Yoko Arase, Tomoko Ishimori, Hiroyuki Satoh, Mika Kanazawa, Ayumi Tate, Kozue Takatsuki, and Keiko Tominaga. We also thank Phoebe Chi, MD, and Melissa Leffler, MBA, from Edanz (https://jp.edanz.com/ac) for editing a draft of this manuscript.
The protocol for this study was approved by the Ethics Committees of Hoshi General Hospital (Date:March 15, 2015;Reference number: 27-3). This study complies with the World Medical Association Declaration of Helsinki.
All authors declare no conflicts of interest regarding the publication of this article.
