Epidemiology of new daily persistent headache: A systematic review and meta-analysis with comparison in regard to different age groups, sex, and patient sample settings.

Objective: This study aimed to synthesize the existing evidence and determine the prevalence of new daily persistent headache (NDPH) in relation to different population settings and age groups, evaluate sex-related patterns, and explore diagnostic challenges.

Background: NDPH is a rare primary headache disorder with poorly documented epidemiological data. This condition is characterized by the sudden onset of an unremitting headache that can resemble other chronic phenotypes. The limited recognition in clinical practice and various clinical presentations often contribute to its initial misclassification and delayed diagnosis.

Methods: A systematic review and a meta-analysis were conducted by searching Pubmed/Medline, ScienceDirect, and Embase from the inception of each database until April 24, 2025. Pooled prevalence estimates were calculated for general and clinic-based populations, separately for adults and children/adolescents with or without a diagnosis of chronic daily headache whenever possible. Age at onset and sex differences were also analyzed. This study was designed in accordance with the Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines. We assessed the risk of bias using the Joanna Briggs Institute Checklist for Studies Reporting Prevalence Data. The protocol of this study was pre-registered on PROSPERO (ID: CRD42024607748).

Results: Out of the initial 14,844 entries, 30 studies involving 74,253 individuals qualified for inclusion in this study. According to the critical appraisal tool, 27 articles were assessed as having "low" risk of bias, while three articles were rated as having "moderate" risk. The prevalence of NDPH was 0.06% (95% confidence interval [CI]: 0.02-0.18) in the general adult population. In patients evaluated for a headache in a headache-oriented clinic, NDPH was present in 1.23% (95% CI: 0.67-2.23, 95% prediction interval [PI]: 0.11%-12.65%; I² = 95.73) of adults and in 2.39% (95% CI: 0.48-11.12) of children. Among those with chronic daily headache, prevalence was 3.91% (95% CI: 2.45-6.18, 95% PI: 0.75%-18.01%) in adults and 19.60% (95% CI: 14.25-26.35, 95% PI: 6.32%-46.82%) in children. Females tended to be affected more frequently, although these differences did not consistently reach statistical significance. The pooled mean age at onset was 40.44 years (95% CI: 24.51-56.38) among adults in the general population, whereas among individuals with chronic daily headache, it was 36.99 years (95% CI: 33.45-40.54) in adults and 10.73 years (95% CI: 10.22-11.24) in children.

Conclusion: Our results show that NDPH is a rare headache disorder both in general and in the clinic-based population. Furthermore, NDPH is substantially more frequent in adolescents in comparison to adults, both among patients experiencing any headache and among patients with chronic daily headache.