Pathophysiological Changes in Individuals with Chronic Pain, Absence of a Multidimensional Assessment, and criteria for Prescribing Therapeutic Exercise: Systematic review of the Current Literature

Introduction: This systematic review aimed to analyze the current scientific literature on the practice of physical exercises in the treatment of Chronic Pain, the pathophysiological changes present in these individuals, and the criteria for prescribing exercises. Methods: We used the PRISMA model to prepare this review, which was registered on the PROSPERO platform under registration number CRD42024618037. The review question was "What are the neurofunctional and biomechanical alterations present in individuals with chronic pain? And what are the clinical parameters and criteria for prescribing exercises for pain treatment?". We searched the PubMed Central, EBESCO, Virtual Health Library (VHL), Scielo, Pedro, and Cochrane Library databases for systematic reviews with meta-analyses published in the last 5 years. The selected studies were evaluated qualitatively using the AMSTAR 2 method and quantitatively using descriptive statistics (prevalence, mean, and incidence), presented in narrative format, tables, and graphs. Results: We selected 40 systematic reviews with meta-analysis, published in 16 countries, that analyzed 111,531 individuals, with a mean of 12,392.33 per study (standard deviation 32,157.86), encompassing both genders and individuals aged between 14 and 80 years. We assessed the methodological quality of the studies using the AMSTAR 2 method, presenting high methodological quality for 72.9% (29 studies) of the Meta-Analysis, 15% (6 studies) of Moderate quality, and 12.5% (5 studies) of Critically Low quality. The pathologies analyzed were Low Back pain, Neck pain, Fibromyalgia, chronic Fatigue syndrome, Musculoskeletal Pain, Upper limb and insertional Achilles tendon tendinopathy, anterior Knee pain, and knee and Hip Osteoarthritis. We analyzed a total of 28 exercise modalities, with therapeutic exercise having the highest prevalence. We observed differences between genders in different pathologies. Therapeutic exercise demonstrated significant improvement in short-term pain and in improving functional capacity, but higher-quality studies and objective evaluation of clinical improvement are still needed. Individuals with chronic pain presented pathophysiological changes used as justification for the studies, but these were not evaluated, given the lack of criteria for exercise prescription. No study presented an evaluation of Kinesiophobia, 29 studies evaluated Functional Capacity, obtaining a Clinical improvement of 55%, Pain was evaluated by 31 studies and obtained a clinical improvement of 50%, Quality of Life was evaluated by only 9 studies, obtaining a clinical improvement of 5%. We observed a total of 55 methods used for evaluation, 76% performed subjective evaluation, and 24% evaluation with objective methods, with functional capacity evaluated objectively in 33% of their evaluations, and Pain in 2%. The Visual Analog Scale (VAS) and the Numerical Rating Scale (NRS) were the most prevalent pain assessments, and 3% of pain assessments were performed by intra-articular blood collection (inflammatory and pro-inflammatory biomarkers). We conclude that this study may help researchers and clinicians gain a more comprehensive understanding of the complexity of evidence-based clinical practice in physical exercise for pain treatment.