This study demonstrated that QOL (measured with the EQ-5D) is closely related to pain levels (measured with the BPI), self-efficacy (measured with the PSEQ), pain disability (measured with the PDAS), and sleep disorders (measured with the AIS).
The pathology of chronic musculoskeletal pain is characterized by a complex combination of biological and psychosocial components. The causal relationship between pain and pain-related factors is less clear in longer-term musculoskeletal pain. Furthermore, pain behavior and psychosocial factors related to pain may become more interlinked. The International Association for the Study of Pain has reported that changes in physical and psychosocial factors from chronic musculoskeletal pain include muscle weakness and deconditioning associated with a reduction in daily activity, malnutrition, somnipathy, drug dependence, dependence on family, isolation from family or society, a decline in job performance (e.g., presenteeism and absenteeism), and economic burden. These factors may prolong pain duration and reduce the effects of treatment. The International Association for the Study of Pain recommends evaluating various aspects of patients’ pain for a multidisciplinary treatment approach. A multidisciplinary approach has been used in the USA and Europe since Bonica highlighted the necessity of such an approach in the 1950s . Interventions using a multidisciplinary approach for patients with chronic musculoskeletal pain include patient education, exercise therapy and psychotherapy based on patient-centered cognitive behavioral therapy, and pain-coping training, which is delivered by professional teams. Professional teams consist of health professionals, such as orthopedic surgeons, psychiatrists, anesthesiologists, physicians, neurologists, dentists, nurses, physical therapists, occupational therapists, clinical psychologists, pharmacists, nutritionists, and social workers. Each professional considers the patient’s pathology after evaluation and following discussions in an open conference. However, little is known about which factors affect QOL in patients with chronic musculoskeletal pain.
Previous studies have assessed the interaction between QOL and chronic pain (Table 3). Damush et al. found that physical function was not associated with QOL in older adult women . Pereira et al. evaluated the variables, such as psychological morbidity, illness representations, pain, and coping, that contribute to QOL and analyzed the moderating effect of illness-focused and wellness-focused coping on the relationship between pain interference and QOL in patients with chronic pain. They concluded that 1) the use of wellness-focused coping and being active were associated with better physical QOL, and psychological morbidity contributed to mental QOL; 2) illness-focused and wellness-focused coping moderated the relationship between pain interference and physical QOL but not mental QOL; and 3) because pain interference is positively related to psychological morbidity, and psychological morbidity is negatively related to QOL, the evaluation and promotion of patient coping strategies that are focused on well-being to improve QOL are vital . In a Greek study, Rapti et al. showed using univariate analysis that individuals who had experienced chronic pain and depression showed lower health-related QOL and found a substantial negative correction between QOL and pain and depression scores using regression analysis . Leadley et al. concluded in their review that 1) there is strong evidence of a correlation between pain severity and QOL, 2) there is some evidence that chronic pain treatment can reduce pain and simultaneously improve QOL, and 3) prevention and treatment of chronic pain may be an important contributor to increasing a healthy lifespan . Keilani et al. reported that physical and psychological dimensions of QOL notably affect both pain perception and sleep quality, and thus, modify the association between pain perception and sleep quality . Other studies have indicated a high prevalence of chronic back pain and a substantial burden on QOL .
Thus, previous findings have suggested that various physical and psychological factors are related to QOL. Importantly, chronic musculoskeletal pain is associated with both physical and mental well-being, and chronic musculoskeletal pain is associated with poor QOL. These findings are consistent with the results of a 2001 national survey in Spain using the Health Assessment Questionnaire and the Short Form Health Survey-12, which found that musculoskeletal diseases significantly reduce both QOL and function . Chronic back pain is associated with similar mental health impairments but with greater physical impairment . Chronic pain is often linked to disruptions in daily activities, disability, unemployment, psychological effects, and drug abuse . A case-control analysis of insurance claims data in the USA showed that patients with chronic lower back pain had greater comorbidity burdens than those of the control group and experienced substantially higher frequencies of musculoskeletal pain, neuropathic pain, depression, anxiety, and sleep disorders . The present findings indicate similar comorbidity patterns among patients with chronic musculoskeletal pain.
There are few exploratory studies on psychosocial factors associated with improvements in QOL. Previous studies have indicated that the following factors are associated with QOL: 1) pain catastrophizing and social participation, 2) pain and depression scores (a negative association), 3) depression, anxiety, and mobility in daily activities associated with chronic musculoskeletal pain, and 4) pain perception and sleep quality (Table 3). However, the present study sought to identify the determinants of chronic musculoskeletal pain and examine the association between chronic musculoskeletal pain and QOL. We examined the associations between QOL and pain levels, self-efficacy, pain disability, and sleep disorders. Therefore, there are some differences between the results of this exploratory study and previous study findings on the psychosocial factors associated with QOL. We found that QOL was strongly associated with pain levels, self-efficacy, pain disability, and sleep disorders, and weakly associated with PCS (rumination, magnification, and helplessness) and HADS (anxiety and depression) scores. Our multiple regression analysis explored the factors that had stronger associations with QOL for patients with chronic musculoskeletal pain in our hospital. These data on the psychosocial factors associated with QOL may help to raise awareness among medical staff who use multidisciplinary approaches to pain management. Moreover, they may inform health policymakers on the need for prevention, early diagnosis, proper pain management, and rehabilitation policies to minimize the burdens associated with chronic musculoskeletal pain.
There are several important study limitations. First, we did not analyze differences in pain region and/or type of pain in detail because we restricted the sample to patients with chronic musculoskeletal pain who had valid questionnaire responses who attended checkups at our pain management center. Second, we did not analyze the association between physical function and QOL in this study. Third, we cannot determine how the therapeutic effect of multidisciplinary pain treatment affected the factors associated with QOL because we evaluated these factors before treatment. Future studies should assess the factors that affect QOL after multidisciplinary pain treatment.