Validity of stroke severity assessment using medical records in a population-based cohort.

OBJECTIVES: Stroke severity is an important prognostic indicator of morbidity and mortality, but often not recorded outside of specialised stroke centres. We aimed to develop a scoring rule and validate standardised assessment of the National Institutes of Health Stroke Scale (NIHSS) from medical records. METHODS: We developed a standardised assessment of the NIHSS from medical records. Four trained raters independently assessed the charts of 100 patients with first-ever stroke, randomly selected from the population-based Rotterdam Study cohort. Interrater agreement was determined using the intraclass correlation coefficient (ICC), and Fleiss' kappa for major versus minor stroke. We validated the scoring method against 29 prospective, clinical NIHSS ratings, using Kendall's tau and Cohen's kappa. RESULTS: Of 100 included patients with stroke (mean age 80 years, 62% women), 71 (71%) were admitted to hospital and 9 (9%) were seen in outpatient clinic, whereas 20 (20%) were treated exclusively by their general practitioner or nursing home physician. Interrater agreement for retrospective, chart-based NIHSS ratings was excellent when assessed continuously (ICC: 0.90), and for minor versus major stroke (for NIHSS>3: κ=0.79, NIHSS>5: κ=0.78). Interrater agreement was good both for hospital-based and out-of-hospital settings (ICC: 0.97 and 0.75 respectively). Overall, assessment from medical records was in excellent agreement with prospective NIHSS ratings (τ=0.83; NIHSS>3: κ=0.93, and NIHSS>5: κ=0.93). However, for severe stroke (NIHSS>10) retrospective assessment tended to underestimate severity by 1-3 points on the NIHSS, which was accompanied by a somewhat lower interrater agreement for those more severe cases (NIHSS>10: κ=0.62). CONCLUSIONS: Assessment of stroke severity according to the NIHSS on the basis of medical records is feasible and reliable in population-based cohorts of patients with stroke. These findings facilitate more individualised risk estimates in observational studies that lack prospective ascertainment of stroke severity.

Migraine and the risk of stroke in a middle-aged and elderly population: A prospective cohort study.

BACKGROUND: It has been suggested that patients with migraine have a higher risk of stroke. Despite considerable research on this topic in younger populations, a clear answer is still lacking for older individuals. We studied the association between migraine and the risk of stroke in a middle-aged and elderly population. METHODS: Within the ongoing prospective population-based Rotterdam Study, the presence of migraine was assessed using a validated questionnaire in a structured interview between 2006 and 2011, which formed the baseline. The association between migraine and the risk of stroke was analyzed using Cox proportional-hazards models with adjustments for age, sex, and cardiometabolic risk factors. RESULTS: A total of 6925 (mean age 65.7 ± 11.3 years, 57.8% females) stroke-free participants were included. At baseline, 1030 (14.9%) participants had lifetime history of migraine. During a median follow-up of 6.2 years, 195 participants developed a stroke (163 ischemic stroke). Analyzing the association between migraine and stroke, we found a hazard ratio of 1.44 with a 95% confidence interval of 0.96-2.15. The results were similar for the ischemic stroke (HR 1.50, CI: 0.97-2.32). CONCLUSION: Our data suggested an association between migraine and the risk of stroke in a middle-aged and elderly population, but this was not statistically significant.

Vitamin D Status and Risk of Stroke: The Rotterdam Study.

Background and Purpose- Recent findings suggest that vitamin D, a neuroprotective prohormone, is involved in the pathogenesis of cardiovascular disease. However, previous studies investigating the association between vitamin D and stroke have shown inconsistent findings. In view of these discrepancies, we determined the association of vitamin D status with stroke using data from a population-based study. Methods- Within the RS (Rotterdam Study), an ongoing prospective population-based study, we measured serum 25-hydroxyvitamin D concentrations between 1997 and 2008 in 9680 participants (56.8% women) aged ≥45 years. We assessed a history of stroke at baseline and subsequently followed for incident stroke until January 1, 2016. Regression models were used to investigate the association of serum 25-hydroxyvitamin D with prevalent and incident stroke separately, adjusted for age, sex, study cohort, season of blood sampling, and other cardiovascular risk factors. Results- Of 9680 participants, 339 had a history of stroke at baseline. Serum 25-hydroxyvitamin D concentration was associated with prevalent stroke, adjusted odds ratio per SD decrease, 1.31; 95% CI, 1.14-1.51. After excluding participants with prevalent stroke, we followed 9338 participants for a total of 98 529 person-years. During follow-up, 735 participants developed a stroke. Lower serum 25-hydroxyvitamin D concentration was not associated with a higher stroke risk, adjusted hazard ratio per SD decrease, 1.06; 95% CI, 0.97-1.16. However, severe vitamin D deficiency did show a significant association: hazard ratio, 1.25; 95% CI, 1.05-1.50. Conclusions- In this population-based cohort, we found an association between vitamin D and prevalent stroke. Only severe vitamin D deficiency was associated with incident stroke. This suggests that lower vitamin D levels do not lead to a higher stroke risk but are instead a consequence of stroke.