Prevalence and incidence rates of 17 neuromuscular disorders: An updated review of the literature

Background: Epidemiological frequency measures serve as reference point for patients, clinicians, researchers, and policymakers. Previously, we published a comprehensive review of the literature with prevalence and incidence rates for thirty neuromuscular disorders frequently encountered in the neuromuscular clinic. No meta-analyses were available at the time. Objective: We included various new studies and meta-analyses that have been published since 2014, we aim to update our previous review. Methods: Pubmed was searched for ‘incidence’ and ‘prevalence’ in combination with seventeen acquired and inherited neuromuscular disorders to identify peer-reviewed literature from 1990 to 2023. If multiple prevalence and incidence rates were found, these were summarized by providing the mean, the number of the estimates on which the mean was based and the range of these estimates. Additionally, we searched for meta-analyses to compare the found mean prevalence rates based on the summary of individual studies with the pooled prevalence rates based on the meta-analyses. Results: The mean prevalence estimates for 17 disorders ranged from 0.3/100,000 population for Lambert-Eaton myasthenic syndrome, glycogenosis type V and nemaline myopathy to 20/100,000 for Charcot-Marie-Tooth disease type I. We found annual incidence rates for eight disorders, ranging from 0.3/100,000 population for progressive (spinal) muscular atrophy and facioscapulohumeral muscular atrophy to 1/100,000 for Charcot-Marie-Tooth disease type 1 and myotonic dystrophy type 1. Plotting the mean prevalence estimates from the current study against the pooled prevalence estimates from eight meta-analyses showed reasonable agreement. Conclusions: Epidemiological frequencies about neuromuscular diseases- and in particular data on incidence are scarce. The mean prevalence estimates based on recently published studies on individual cohorts correspond well with the findings from the sparingly performed meta-analyses.