Saini, Camille

Estimates of fibromyalgia prevalence vary widely worldwide due to differences in diagnostic criteria, study methodology, and population characteristics. Accurate estimates are essential to inform population-level surveillance, guide resource allocation, and highlight disparities in disease recognition and access to care. The objective of this systematic review and meta-analysis was to determine the global prevalence of fibromyalgia in the general population, and secondarily to identify factors moderating prevalence variation and to assess prevalence in defined at-risk subpopulations. Pooled prevalence estimates with 95% confidence intervals (CIs) were calculated using the inverse variance heterogeneity model with Freeman–Tukey transformation. Subgroup analyses were performed by sex, diagnostic criteria, country, and other study characteristics, and meta-regression assessed moderators including publication year and Human Development Index (HDI). Of 21,645 records identified, 1,728 underwent full-text review and 882 studies were included in the final analysis. Across 38 countries and 30,070,032 individuals (188 studies), the pooled fibromyalgia prevalence in the general population was 1.40% (95% CI, 0.49–2.47), with substantial heterogeneity (I 2 = 100%) and very low certainty of evidence. Among at-risk subpopulations (9,771,123 participants; 768 studies), prevalence was markedly higher in autoimmune and inflammatory conditions, such as chronic urticaria (37.1%), interstitial cystitis (30.8%), systemic sclerosis (20.6%), celiac disease (20.5%), and inflammatory bowel disease (19.9%), and elevated in chronic pain, rheumatologic, and post-infection cohorts. Meta-regression identified publication year (β = 0.008, P < .001) and HDI (β = 0.725, P = .002) as significant moderators of prevalence. In conclusion, fibromyalgia affects 1% to 2% of the global population, with substantially higher rates in at-risk subpopulations. Temporal and socioeconomic trends emphasize diagnostic inconsistency and global disparities in care.

BACKGROUND: Complex regional pain syndrome (CRPS) is a debilitating and painful condition accompanied by sensory, autonomic, trophic, and/or motor abnormalities. Although CRPS is rare in the general population, the prevalence among individuals at higher risk, particularly posttraumatic and postsurgical patients, remains unknown. This study aims to provide a benchmark that quantifies CRPS prevalence in high-risk groups, and offers insights on potential predictors of developing CRPS. METHODS: We conducted a systematic review and meta-analysis to identify studies reporting prevalence of CRPS after an inciting event (eg, fracture, surgery), specifically 12-month and 24-month prevalence (primary outcomes), as well as 3-month and 6-month prevalence (secondary outcomes). Estimates from individual studies were transformed using double-arcsine transformation, and the resulting estimates with 95% confidence interval (CI) were pooled in a meta-analysis using a random-effects model. RESULTS: We included 214 articles with data from 2491,378 participants worldwide (35 countries), of which 16,873 had CRPS. The pooled 12-month and 24-month global prevalence was 3.04% (95% CI, 2.64–3.48) and 6.46% (95% CI, 5.46–7.53), respectively. Subgroup analysis and meta-regression were performed to understand the impact of population-dependent (mechanism of injury, type of CRPS), contextual-dependent (socioeconomic status), and methodological-dependent (study design, publication year) factors. The 12-month prevalence was higher in countries with a high human development index (HDI) compared to those with a medium or very high HDI, was higher in participants with a traumatic inciting injury only versus those with surgical injury only or traumatic/surgical injury, and was higher in prospective versus retrospective studies. Meta-regression analysis showed that publication year was a significant moderator, with more recent articles reporting lower 12-month prevalence. CONCLUSIONS: This study provides a benchmark of the global prevalence of CRPS, which anesthesiologists and pain specialists can use to prioritize early diagnosis and identify those at the highest risk for CRPS.

Introduction Although the prevalence of chemotherapy-induced peripheral neuropathy (CIPN) has been reported, the proportion of patients with CIPN who report chronic moderate-to-severe neuropathy or chronic painful neuropathy remains poorly understood, despite its significant impact on patients’ quality of life and treatment outcomes. Methods A systematic review and meta-analysis were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome was the pooled prevalence of chronic (≥3 months) moderate-to-severe CIPN or painful CIPN among patients diagnosed with CIPN. Estimates from each study were transformed using a double-arcsine transformation and pooled in a meta-analysis using an inverse variance heterogeneity model. Subgroup analysis was conducted based on geographical region, sex, chemotherapy regimen, primary cancer type, and funding source; metaregression analysis was conducted based on study design, human development index (HDI), and publication year. Results 76 studies from 29 countries, encompassing 13 635 patients with CIPN, were included. Among patients diagnosed with CIPN, the pooled prevalence of those reporting chronic moderate-to-severe CIPN or painful CIPN was estimated at 47.76% (95% CI 37.50 to 58.08; 95% prediction interval 24.68–71.84). Substantial heterogeneity was observed across studies ( I² =97.45%; 95% CI for I 2 97.15 to 97.72). Subgroup analysis revealed that patients treated with platinum-based agents and taxanes had the highest prevalence of chronic moderate-to-severe CIPN or painful CIPN (44.47% and 55.68%, respectively), and among primary cancers, those with breast cancer, multiple myeloma, and lung cancer reported the highest prevalence of chronic moderate-to-severe CIPN or painful CIPN (61.31%, 53.55%, and 50.85%, respectively). Study design, HDI, and publication year were non-significant moderators of prevalence estimates. Based on our Grading of Recommendations, Assessment, Development, and Evaluation assessment, the certainty of evidence was considered “very low.” Sensitivity analysis restricted to studies explicitly measuring painful CIPN (40.78%; 95% CI 29.08 to 52.74) or moderate-to-severe CIPN (49.04%; 95% CI 37.16 to 60.95) yielded similar prevalence estimates. Conclusion This study provides the first comprehensive global estimate of the prevalence of chronic moderate-to-severe CIPN or painful CIPN, highlighting its significant burden on patients worldwide. The variation in prevalence across geographical regions, chemotherapy regimens, and primary cancers underscores the need for tailored management strategies and further research to address potential disparities.