Chronic pain is a common condition among people with hemophilia and is associated with joint deterioration because of repeated joint bleeds. This systematic review and meta-analysis aimed to determine the prevalence of chronic pain because of hemophilia and to analyze its interference in the lives of patients, according to Ana Cristina Paredes, a PhD student at the University of Minho, Braga, Portugal, and colleagues.
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The manuscripts included in the study, which was published online in the Journal of Pain, were mostly observational, cross-sectional studies and one prospective investigation, published between 2009 and 2019.
The issue of pain is particularly important among people with hemophilia, as many adult patients suffer from distinct degrees of arthropathy and associated chronic pain, due to the lifelong occurrence of hemarthrosis, the authors noted. In an important distinction, according to the authors, people with hemophilia may therefore experience both acute pain during bleeds and chronic pain caused by joint deterioration. Acute pain ceases with the resolution of the bleeding episode, but the chronic pain is significantly more challenging, since it persists in time and may trigger changes in the nervous system, leading to peripheral or central sensitization.
Data in the assessed studies were collected from a variety of sources: hemophilia centers, online surveys, by mail, or through a national database, with return rates ranging from 29.2% to 98%. Overall, these studies comprised 4,772 adults, with individual sample sizes ranging from 21 to 2,253 patients, the authors added.
Conflicting results
Overall, there was a widely varying prevalence of hemophilia-related chronic pain reported across studies. Additionally, methodologies and sample characteristics varied widely. The meta-analyses revealed high heterogeneity between studies, and, therefore, pooled prevalence estimates values must be interpreted with caution, the authors stated.
All of the 11 selected studies included for meta-analysis and review reported on the prevalence of chronic pain caused by hemophilia. Chronic pain was assessed using direct questions developed by the authors in eight studies and using the European Haemophilia Therapy Standardization Board definition in three studies. The prevalence for global samples ranged widely from 17% to 84%.
Although there was high heterogeneity, the random-effects meta-analysis including all studies demonstrated a pooled prevalence of 46% of patients reporting chronic pain. Subgroup analyses of studies including all disease severities (mild, moderate, and severe; seven studies) revealed a pooled prevalence of 48%, but also with high heterogeneity. Looking at severe patients only (six studies), the chronic pain prevalence ranged from 33% to 86.4%, with a pooled prevalence of 53% and high heterogeneity, the authors added.
The wide disparity of the chronic pain prevalence seen across the studies is likely because of the fact that some investigations inquired about pain without distinguishing between acute (hemarthrosis-related) or chronic (arthropathy-related) pain, and without clarifying if the only focus is pain caused by hemophilia, or including all causes of pain complaints, according to the researchers.
“Concerning hemophilia-related chronic pain interference, it is striking that the existing literature does not distinguish between the impact of acute or chronic pain. Such a distinction is needed and should be made in future studies to ensure accurate accounts of hemophilia-related pain and to fully understand its interference according to the type of pain (acute vs. chronic). This information is relevant to promote targeted and effective treatment approaches,” the researchers concluded.
The research was supported by a Novo Nordisk HERO Research Grant 2015, the Portuguese Foundation for Science and Technology, and the Foundation for Science and Technology in Portugal. The authors declared they had no conflicts of interest.