Impact of early headache neuroimaging on time to malignant brain tumor diagnosis: A retrospective cohort study.

BACKGROUND:Neuroimaging for headaches is both common and costly. While the costs are well quantified, little is known about the benefit in terms of diagnosing pathology. Our objective was to determine the role of early neuroimaging in the identification of malignant brain tumors in individuals presenting to healthcare providers with headaches. METHODS:This was a retrospective cohort study using administrative claims data (2001-2014) from a US insurer. Individuals were included if they had an outpatient visit for headaches and excluded for prior headache visits, other neurologic conditions, neuroimaging within the previous year, and cancer. The exposure was early neuroimaging, defined as neuroimaging within 30 days of the first headache visit. A propensity score-matched group that did not undergo early neuroimaging was then created. The primary outcome was frequency of malignant brain tumor diagnoses and median time to diagnosis within the first year after the incident headache visit. The secondary outcome was frequency of incidental findings. RESULTS:22.2% of 180,623 individuals had early neuroimaging. In the following year, malignant brain tumors were found in 0.28% (0.23-0.34%) of the early neuroimaging group and 0.04% (0.02-0.06%) of the referent group (P<0.001). Median time to diagnosis in the early neuroimaging group was 8 (3-19) days versus 72 (39-189) days for the referent group (P<0.001). Likely incidental findings were discovered in 3.17% (3.00-3.34%) of the early neuroimaging group and 0.66% (0.58-0.74%) of the referent group (P