SUNCT and SUNA, Distinct Disorders or Spectrum of a Single Clinical Entity? A Meta-analysis

A BSTRACT This study aimed to evaluate and compare the relative frequencies of clinical features between SUNCT and SUNA. Recently, many researchers tried to investigate the relationship between them and disputed whether those two headache entities appear distinct or should be reconsidered as a single disorder. PubMed and Embase were searched for observational studies that reported clinical characteristics in adults diagnosed with SUNCT and SUNA, in accordance with ICHD-3 β and/or ICHD-3. To determine the pooled prevalence estimates of the clinical features, a random-effects meta-analysis was performed. The between-study heterogeneity was measured with I2 statistics. The study structure followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias was assessed using Joanna Briggs Institute Checklist for Studies Reporting Prevalence Data. Of the initial 3834 records, 7 studies met eligibility criteria. The mean age of onset did not differ between the groups. A total of 22.9% (95% confidence interval [CI]: 9.5–45.6) subjects with SUNA present with conjunctival injection and 67.0% (95% CI: 29.4–90.9) with lacrimation. The next three most common cranial autonomic symptoms in both SUNCT and SUNA were rhinorrhea, nasal congestion, and ptosis. Restlessness and agitation were present in more than 40.0% of both entities. Single stab attacks were significantly more common in SUNCT (74.3%, 95% CI: 43.2–91.7) than in SUNA (21.8%, 95% CI: 11.3–37.8). In addition, subjects with SUNCT were more likely to benefit from topiramate (37.5%, 95% CI: 27.6–48.4) than SUNA patients (10.0%, 95% CI: 3.8–23.8). The results of our study showed that there were no major differences between SUNCT and SUNA and thus suggesting their common nature.