Cluster headache diagnostic delay and its predictors: a systematic review with a meta-analysis.

Background: Despite its characteristic clinical expression, cluster headache (CH) often remains unrecognized in clinical practice, with patients suffering from CH having to wait a long time before receiving a correct diagnosis and benefit from appropriate treatment.

Methods: This work is a systematic review of data accessible through PubMed and published up to December 2024, focusing on the delay in CH diagnosis and its predictors. A meta-analysis was performed to estimate the mean CH diagnostic delay using the inverse of variance as the weight. A qualitative analysis was performed to identify predictors of this delay.

Results: Among the 108 studies identified, 22 and 11 were selected for the qualitative analysis and meta-analysis respectively. These selected studies included a total of 8654 subjects (range 23-1604). This whole population was composed of 6383 men, 2180 women and 91 subjects with sex not specified. CH form was indicated for 7177 subjects with 5808, 1182 and 187 with episodic CH, chronic CH and undetermined form respectively. Meta-analysis estimated the overall CH diagnostic delay at 10,43 years (95% CI [9.09; 11.77]) with a reduction in the CH diagnostic delay over time since the sixties and the continuation of such a reduction every decade since 2000. Qualitative analyses identified several predictors of this diagnostic delay. Autonomic symptoms were associated with a decrease in the delay of diagnosis, whereas lower age of CH onset, alternating attack side and nocturnal headaches were associated with an increase in the delay of diagnosis.

Conclusion: This systematic review including meta-analysis confirms an important unmet need in terms of CH diagnosis. Further work is needed to identify more precisely the predictors of this delay for better management of patients suffering from CH. TRIAL REGISTRATION: The systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 01/10/2025 (registration number: CRD42025630779).