Consistency between headache diagnoses and ICHD-3 criteria across different levels of care.

Background: Diagnosing headache disorders poses significant challenges, particularly in primary and secondary levels of care (PSLC), potentially leading to misdiagnosis and underdiagnosis. This study evaluates diagnostic agreement for migraine, tension-type headache (TTH), and cluster headache (CH) between PSLC and tertiary care (TLC) and assesses adherence to the International Classification of Headache Disorders 3rd edition (ICHD-3) guidelines.

Methods: A retrospective, cross-sectional analysis was conducted at Charité - Universitätsmedizin Berlin's tertiary headache center. The patients' self-reported diagnoses from the PSLC were compared with those in TLC and with ICHD-3 criteria. Cohen's kappa (κ) and R² were used to assess diagnostic agreement.

Results: Among 1,468 patients (43.4 ± 14.4 years; 74.5% women), 69.5% reported a diagnosis in PSLC, and 99.5% were diagnosed at their first TLC visit. Overall agreement between PSLC and TLC was 80% (κ = 0.55; R²=30%). Agreement between the PSLC and ICHD-3 was 77% for migraine, 82% for TTH, and 96% for CH (κ = 0.65; R²=41%). TLC diagnoses aligned with ICHD-3 in over 90%.

Conclusion: Our findings indicate a significant degree of diagnostic agreement across different levels of care according to the ICHD-3 guidelines. However, there remains insufficient reliability in clinical diagnostics, highlighting the need for continued efforts to improve the early recognition and diagnostic accuracy and consistency of primary headaches to optimize patient care and treatment outcomes in Germany.