Incidence and prevalence of small fibre neuropathy in the Netherlands: a multiple system estimation study

BACKGROUND: Small fibre neuropathy (SFN) affects small myelinated Aδ- and unmyelinated C-fibres and causes neuropathic pain and autonomic symptoms. Earlier Dutch estimates, over a decade old, reported a minimum prevalence of 52.95 and an incidence of 11.75 per 100 000 adults. As recognition of SFN has likely increased, this study aimed to estimate the total SFN population in the Netherlands and to provide updated incidence and prevalence rates using a multiple system estimation (MSE) approach. METHODS: MSE was used to estimate the total adult SFN population by matching patients from three national databases: the SFN expertise centre, the national SFN registry and the Dutch Neuromuscular Disorders Association. Prevalence was calculated by using total population numbers from Statistics Netherlands, adjusting for mortality with age- and sex-specific survival rates. Annual incidence and prevalence by sex and region were calculated using stratified MSE. Missing diagnosis years in the patient association data were imputed using multiple imputations. RESULTS: The prevalence of SFN in 2024 was estimated at 69.69 and the incidence at 3.55 per 100 000 adults in the general Dutch population, with higher rates in females. Incidence increased over time, particularly among females. CONCLUSIONS: This study reveals a higher prevalence than previously reported. The lower incidence compared with previous estimates likely reflects differences in geographic coverage, while the rising trend suggests increasing awareness and recognition of SFN. These findings suggest that SFN represents a larger problem than previously recognised and the burden of SFN emphasises the urgent need for novel therapeutic strategies.