Sensitivity of the SNNOOP10 list in the high-risk secondary headache detection

Aim To evaluate the diagnostic accuracy of the SNNOOP10 list in the detection of high-risk headaches. Methods Patients that visited the Hospital Clinico San Carlos (Madrid) emergency department due to headache that were allocated to a Manchester Triage System level between critical and urgent were prospectively included but retrospectively analysed. A researcher blind to the patients' diagnosis administered a standardised questionnaire and afterwards a neurologist blind to the questionnaire results diagnosed the patient according to the International Classification of Headache Disorders. The primary endpoint was to assess the sensitivity of the SNNOOP10 list in the detection of high-risk headaches. Secondary endpoints included the evaluation of the sensitivity, specificity, positive predictive value, negative predictive value and area under the curve of each SNNOOP10 item. Results Between April 2015 and October 2021, 100 patients were included. Patients were 44 years old (inter-quartile range: 33.6-64.7) and 57% were female. We identified 37 different diagnoses. Final diagnosis was a primary headache in 33%, secondary headache in 65% and cranial neuralgia in 2%. There were 46 patients that were considered as having high-risk headache. Patients from the primary headache group were younger and more frequently female. Sensitivity of SNNOOP10 list was 100% (95% confidence interval: 90.2%-100%). The items with higher sensitivity were neurologic deficit or disfunction (75.5%), pattern change or recent onset of the headache (64.4%), onset after 50 years (64.4%). The most specific items were posttraumatic onset of headache (94.5%), neoplasm in history (89.1%) and systemic symptoms (89%). The area under the curve of the SNNOOP10 list was 0.66 (95% CI: 0.55-0.76). Conclusion The red flags from the SNNOOP10 list showed a 100% sensitivity in the detection of high-risk headache disorders.