Btained from the mortality registry. The date of the first occurrence of a principal diagnosis of HS (SIS 3 site ICD-9-CM codes 430, 431, or 432) within the follow-up period was defined as the primary endpoint. All subjects were followed from the index visit to the first occurrence of HS, death, or end of follow-up. The data for preexisting cardiovascular comorbidities, including diabetes mellitus (ICD-9-CM code 250), hypertension (ICD-9-CM codes 401?05), hyperlipidemia (ICD-9-CM code 272), coronary heart disease (ICD-9-CM codes 410?14, and 429.2), chronic rheumatic heart disease (ICD-9-CM codes 393?98), and other types of heart disease (ICD-9-CM codes 420?29), were acquired by tracking all ambulatory medical care and inpatient records in the NHI database in the year before the index visit. Since hypertension is an important risk factor of HS, we also included the information on the use of antihypertensive medication (e.g. angiotensin convertingMigraine and Risk of Hemorrhagic StrokeTable 1. Demographic and clinical characteristics of the migraine and non-migraine groups.Total sample, N = 125550 Migraine group Variable Women Age, y Hypertension Diabetes Hyperlipidemia Coronary heart disease Chronic rheumatic heart disease Other heart disease Use of anticoagulant medication Note: Values are expressed as the mean 6 SD or n ( ). doi:10.1371/journal.pone.0055253.t001 N = 20925 14583(69.7) 42.8615.2 3248(15.5) 1255(6.0) 1664(8.0) 1481(7.1) 107(0.5) 1538(7.4) 35(0.2) Non-migraine group N = 104625 72915(69.7) 42.6615.2 12024(11.5) 6119 (5.9) 5626(5.4) 4506(4.3) 351(0.3) 4027(3.9) 187(0.2) P value 1.0000 0.1608 ,0.0001 0.4024 ,0.0001 ,0.0001 0.0001 ,0.0001 0.without antihypertensive medication, diabetes, and chronic rheumatic heart disease. The subgroup analysis of the crude and adjusted HRs of HS is presented in Table 3, the subjects in the migraine group being classified into 3 subgroups according to the presence or absence of aura: (1) migraine with aura (MA, ICD-9-CM codes 346.0); (2) migraine without aura (MO, ICD-9-CM codes 346.1); and (3) uncategorized migraine (MU, ICD-9-CM codes other than 346.0 or 346.1). All 3 subgroups had a significantly increased risk of HS compared to the non-migraine group, regardless of the presence or absence of aura. Table 4 shows the subgroup analysis stratified by sex and age. For all sex and age strata, the migraine group had a consistently higher adjusted HR than the non-migraine group. The interaction between migraine and either sex or age was not statistically significant in the multivariate analysis. We also compared the distribution of HS subtypes 1662274 between the migraine and non-migraine groups. Thirty-three (29.2 ) of the 113 HS events in the migraine group, and 49 (19.2 ) of the 255 HS events in the non-migraine group were subarachnoid hemorrhage (ICD-9-CM code 430). The migraine group had a higher proportion of subarachnoid hemorrhage in HS events 1317923 (Chi-square test, P = 0.0337). In addition, we conducted a sensitivity analysis on whether migraine is predictive of fatal or non-fatal HS. The results show that migraine was predictive of non-fatal HS (adjusted HR 2.24, 95 CI, 1.76 ?2.85; P,0.0001). However, there was lack of statistically significant association between migraine and fatal HS (adjusted HR 1.49, 95 CI, 0.82 ?2.73; P = 0.1926).DiscussionIn the Methyl linolenate web present population insurance registry- based, age- and sex- matched follow-up study, we found migraine was associated with an increased risk of HS. Migraineurs.Btained from the mortality registry. The date of the first occurrence of a principal diagnosis of HS (ICD-9-CM codes 430, 431, or 432) within the follow-up period was defined as the primary endpoint. All subjects were followed from the index visit to the first occurrence of HS, death, or end of follow-up. The data for preexisting cardiovascular comorbidities, including diabetes mellitus (ICD-9-CM code 250), hypertension (ICD-9-CM codes 401?05), hyperlipidemia (ICD-9-CM code 272), coronary heart disease (ICD-9-CM codes 410?14, and 429.2), chronic rheumatic heart disease (ICD-9-CM codes 393?98), and other types of heart disease (ICD-9-CM codes 420?29), were acquired by tracking all ambulatory medical care and inpatient records in the NHI database in the year before the index visit. Since hypertension is an important risk factor of HS, we also included the information on the use of antihypertensive medication (e.g. angiotensin convertingMigraine and Risk of Hemorrhagic StrokeTable 1. Demographic and clinical characteristics of the migraine and non-migraine groups.Total sample, N = 125550 Migraine group Variable Women Age, y Hypertension Diabetes Hyperlipidemia Coronary heart disease Chronic rheumatic heart disease Other heart disease Use of anticoagulant medication Note: Values are expressed as the mean 6 SD or n ( ). doi:10.1371/journal.pone.0055253.t001 N = 20925 14583(69.7) 42.8615.2 3248(15.5) 1255(6.0) 1664(8.0) 1481(7.1) 107(0.5) 1538(7.4) 35(0.2) Non-migraine group N = 104625 72915(69.7) 42.6615.2 12024(11.5) 6119 (5.9) 5626(5.4) 4506(4.3) 351(0.3) 4027(3.9) 187(0.2) P value 1.0000 0.1608 ,0.0001 0.4024 ,0.0001 ,0.0001 0.0001 ,0.0001 0.without antihypertensive medication, diabetes, and chronic rheumatic heart disease. The subgroup analysis of the crude and adjusted HRs of HS is presented in Table 3, the subjects in the migraine group being classified into 3 subgroups according to the presence or absence of aura: (1) migraine with aura (MA, ICD-9-CM codes 346.0); (2) migraine without aura (MO, ICD-9-CM codes 346.1); and (3) uncategorized migraine (MU, ICD-9-CM codes other than 346.0 or 346.1). All 3 subgroups had a significantly increased risk of HS compared to the non-migraine group, regardless of the presence or absence of aura. Table 4 shows the subgroup analysis stratified by sex and age. For all sex and age strata, the migraine group had a consistently higher adjusted HR than the non-migraine group. The interaction between migraine and either sex or age was not statistically significant in the multivariate analysis. We also compared the distribution of HS subtypes 1662274 between the migraine and non-migraine groups. Thirty-three (29.2 ) of the 113 HS events in the migraine group, and 49 (19.2 ) of the 255 HS events in the non-migraine group were subarachnoid hemorrhage (ICD-9-CM code 430). The migraine group had a higher proportion of subarachnoid hemorrhage in HS events 1317923 (Chi-square test, P = 0.0337). In addition, we conducted a sensitivity analysis on whether migraine is predictive of fatal or non-fatal HS. The results show that migraine was predictive of non-fatal HS (adjusted HR 2.24, 95 CI, 1.76 ?2.85; P,0.0001). However, there was lack of statistically significant association between migraine and fatal HS (adjusted HR 1.49, 95 CI, 0.82 ?2.73; P = 0.1926).DiscussionIn the present population insurance registry- based, age- and sex- matched follow-up study, we found migraine was associated with an increased risk of HS. Migraineurs.