We conducted a 3-year annual questionnaire survey of the International Headache Society (IHS) migraine diagnoses among 2414 adolescents aged 13. For those with migraine without aura (IHS 1.1) at the baseline survey (n = 89), 28% and 24% retained the IHS 1.1 diagnosis at the 2nd and 3rd surveys. Only 0.5% of adolescents had a persistent IHS 1.1 diagnosis for 3 years. Of those with IHS 1.1 or migrainous disorder (IHS 1.7) (n = 449), 43% and 48% retained the IHS 1.1 or IHS 1.7 diagnosis at the 2nd and 3rd surveys. Conversion between IHS 1.1 and IHS 1.7 was common. About 5.6% of the adolescents suffered from IHS 1.1 or IHS 1.7 for all 3 years. Independent predictors for persistent IHS 1.1 or IHS 1.7 diagnosis included frequent headache (>5 days/month) (relative risk (RR) = 1.8) and pulsatile headache (RR = 1.5). The diagnosis of IHS 1.1 in adolescents was quite unstable. Conversion between IHS 1.1 and IHS 1.7 was an important cause. Factoring IHS 1.7 into the spectrum of migraine diagnoses during epidemiological surveys provides a realistic impression of the disease burden in this age group.

Warfarin significantly reduces thromboembolic risk, but perceptions of associated bleeding risk limit its use. The evidence supporting the association between bleeding and individual patient risks factors is unclear. This systematic review aims to determine the strength of evidence supporting an accentuated bleeding risk when patients with risk factors listed in the warfarin prescribing information are prescribed the drug. A systematic literature search of MEDLINE and Cochrane CENTRAL was conducted to identify studies reporting multivariate relationships between prespecified covariates and the risk of bleeding in patients receiving warfarin. The prespecified covariates were identified based on patient characteristics for bleeding listed in the warfarin package insert. Each covariate was evaluated for its association with specific types of bleeding. The quality of individual evaluations was rated as 'good', 'fair' or 'poor' using methods consistent with those recommended by the Agency for Healthcare Research and Quality (AHRQ). Overall strength of evidence was determined using the Grading of Recommendations Assessment, Development (GRADE) criteria and categorised as 'insufficient', 'very low', 'low', 'moderate' or 'high'. Thirty-four studies, reporting 134 multivariate evaluations of the association between a covariate and bleeding risk were identified. The majority of evaluations had a low strength of evidence for the association between covariates and bleeding and none had a high strength of evidence. Malignancy and renal insufficiency were the only two covariates that had a moderate strength of evidence for their association with major and minor bleeding respectively. The associations between covariates listed in the warfarin prescribing information and increased bleeding risk are not well supported by the medical literature.