Predictive value of stroke discharge diagnoses in the Danish National Patient Register

Aims: To determine the positive predictive values for stroke discharge diagnoses, including subarachnoidal haemorrhage, intracerebral haemorrhage and cerebral infarction in the Danish National Patient Register. Methods: Participants in the Danish cohort study Diet, Cancer and Health with a stroke discharge diagnosis in the National Patient Register between 1993 and 2009 were identified and their medical records were retrieved for validation of the diagnoses. Results: A total of 3326 records of possible cases of stroke were reviewed. The overall positive predictive value for stroke was 69.3% (95% confidence interval (CI) 67.8–70.9%). The predictive values differed according to hospital characteristics, with the highest predictive value of 87.8% (95% CI 85.5–90.1%) found in departments of neurology and the lowest predictive value of 43.0% (95% CI 37.6–48.5%) found in outpatient clinics. Conclusions: The overall stroke diagnosis in the Danish National Patient Register had a limited predictive value. We therefore recommend the critical use of non-validated register data for research on stroke. The possibility of optimising the predictive values based on more advanced algorithms should be considered. </jats:p

Intake of marine n-3 polyunsaturated fatty acids and risk of hemorrhagic stroke and its subtypes:a Danish follow-up study

BACKGROUND: A diet rich in marine n-3 polyunsaturated fatty acids (PUFAs) may lower the risk of coronary heart disease and ischemic stroke. However, the association between intake of marine n-3 PUFAs and risk of hemorrhagic stroke has only been sparsely explored. We aimed to investigate the associations between intake of the major marine n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and their sum in relation to incident hemorrhagic stroke and its subtypes intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH).METHODS: We analyzed data from the Danish Diet, Cancer and Health Cohort, which was established between 1993 and 1997. Information on dietary intake of marine n-3 PUFAs was obtained through a validated food frequency questionnaire. Potential hemorrhagic stroke cases were identified by linkage to the Danish National Patient Register and subsequently validated. Hazard ratios obtained by Cox proportional hazard regression were used as measures of association.RESULTS: A total of 394 subjects among 55,519 individuals developed hemorrhagic stroke during a median follow-up period of 13.5 years. In multivariable analyses including adjustment for established risk factors, we observed weak and statistically non-significant indications of inverse associations between intake of EPA, DHA, and EPA + DHA and the rate of incident hemorrhagic stroke. In analyses of hemorrhagic stroke subtypes, we found indications of lower rates of ICH among participants in the highest quartile of EPA, DHA, and EPA + DHA compared with those in the lowest quartile, and indications of lower rates of SAH in the highest quartile of EPA intake compared to the lowest quartile but the findings were statistically non-significant.CONCLUSIONS: Indications of inverse statistically non-significant associations were found between EPA, DHA, and EPA + DHA and hemorrhagic stroke.</p