The Prevalence, Characteristics and Impact of Chronic Pain in Patients with Muscular Dystrophies: A Systematic Review
Background: Chronic pain is a frequent, yet under-recognised and under-assessed problem in people with muscular dystrophies (MDs). Knowledge of the prevalence and characteristics of chronic pain, and its impact on function and quality of life is limited and lacks systematic exploration.
Purpose: This study aims to systematically review and synthesise existing literature that addresses chronic pain prevalence, characteristics and impact in people with different types of MDs.
Methods: A systematic search of bibliographic electronic databases was performed for articles (up to March 2020) reporting chronic pain (pain persisting ≥ 3 months) in people with MDs. Quality assessment was conducted using the Risk of Bias Tool for Prevalence Studies. Pooled estimates of pain prevalence and average pain intensity were calculated for each diagnostic group and where the number of articles was sufficient, group comparison was performed.
Results: The estimated prevalence of chronic pain is similar across diagnostic groups of MDs: 68% in FSHD, 65% in DM, 62% in BMD/DMD, and 60% in LGMD. Generally, chronic pain is reported as mild to moderate by most people with FSHD and DM, with a mean value of moderate pain intensity (4.1/10 in FSHD and 4.7/10 in DM, respectively). Lower back, shoulder and legs are the most frequent sites of chronic pain among people with FSHD, DM, BMD/DMD, and LGMD, with minor variations. Diffuse pain across multiple body sites was reported by a notable proportion of these individuals. No clear pattern of pain descriptors relating to a specific diagnostic group of MDs could be identified from the included studies. Chronic pain has a negative impact on daily life activities in people with MDs, and may also contribute decreased quality of life. Occupational and domestic activities, recreational activities and mobility are the daily life domains most commonly affected by chronic pain. In children with DMD, mood may be significantly affected. Consistently, sleep is the least affected domain by chronic pain across different forms of MDs.
Implications: This is the first review that systematically explores the prevalence, characteristics and impact of chronic pain in people with MDs. It is also the first to attempt to quantitatively synthesise the prevalence and pain intensity data by diagnostic groups in this population. The present study demonstrates how common chronic pain is across various MD populations and highlights the need for better recognition and understanding of the nature and impact of pain from health professionals. Future studies should focus on chronic pain in lesser explored MDs (including CMD, EDMD, OPMD and Distal MDs), geographic regions outside the USA and Europe and younger age groups. Further investigations on pain phenotypes (e.g. neuropathic vs nociceptive pain) and the associated response to treatments are also recommended.