New and Noteworthy Information—July 2013
Atrial fibrillation may be associated with faster cognitive decline, according to a study published online ahead of print June 5 in Neurology. Researchers studied 5,150 men and women 65 or older who did not have atrial fibrillation or a history of stroke at baseline. Atrial fibrillation was identified by examining hospital discharge records and annual ECGs. A total of 552 patients (10.7%) developed incident atrial fibrillation during a mean seven years of follow-up. Mean Modified Mini-Mental State Examination (MMMSE) scores declined faster in patients with incident atrial fibrillation than in patients without atrial fibrillation. The predicted five-year decline in mean MMMSE score from age 80 to age 85 was −6.4 points for participants without atrial fibrillation and −10.3 points for participants with incident atrial fibrillation at age 80.
The level of interleukin 17F (IL-17F) in a patient with relapsing-remitting multiple sclerosis (MS) may not predict his or her response to treatment with interferon beta, according to research published online ahead of print June 3 in JAMA Neurology. Researchers analyzed serum samples from 239 randomly selected patients treated with interferon beta-1b (250 μg) for at least two years. Using clinical and MRI criteria, the investigators found that levels of IL-17F measured at baseline and month six did not correlate with lack of response to treatment after two years. Relapses and new lesions on MRI were not associated with pretreatment serum IL-17F levels. The results did not change when patients with neutralizing antibodies were excluded. Patients with levels of IL-17F higher than 200 pg/mL had poor response and clinical or radiologic activity.
Earlier treatment with thrombolytics may be associated with reduced mortality for patients with stroke, according to data published in the June 19 JAMA. Researchers analyzed data from 58,353 patients with acute ischemic stroke who were treated with t-PA within 4.5 hours of symptom onset in 1,395 hospitals. Patients’ median age was 72, 50.3% of patients were women, and median time to treatment was 144 minutes. A total of 5,142 in-hospital deaths occurred. Faster time to treatment, in 15-minute increments, was associated with reduced in-hospital mortality, reduced symptomatic intracranial hemorrhage, increased achievement of independent ambulation at discharge, and increased discharge to home. Patient factors most strongly associated with shorter time to treatment included greater stroke severity, arrival by ambulance, and arrival during regular hours.
High serum iron levels may be associated with a decreased risk of developing Parkinson’s disease, according to a study published June 4 in PLOS Medicine. Researchers investigated three polymorphisms in the genes HFE and TMPRSS6. For each polymorphism, they performed a meta-analysis of studies investigating the genetic effect on iron levels and a meta-analysis of studies investigating the genetic effect on the risk of Parkinson’s disease. Using three Mendelian randomization analyses, the investigators estimated the effect of iron on Parkinson’s disease for the three polymorphisms. Every 10 µg/dl increase in blood iron corresponded to a 3% reduction in the risk of Parkinson’s disease. Thus, increased blood iron levels may have a protective effect against Parkinson’s disease, but the underlying mechanism remains unclear, said the researchers.
Diabetes and dementia may have a bidirectional association, according to research published online ahead of print June 10 in JAMA Internal Medicine. Investigators examined 783 older adults with diabetes who were participating in a prospective population-based study. Subjects’ mean age was 74, and their baseline Modified Mini-Mental State Examination scores were 80 or higher. Approximately 47% of subjects were African American, and 47% were female. During the 12-year follow-up, 61 participants had a reported hypoglycemic event, and 148 developed dementia. Subjects who had a hypoglycemic event had a twofold increased risk for developing dementia, compared with those who did not have a hypoglycemic event. Subjects with diabetes who developed dementia had a greater risk for having a subsequent hypoglycemic event, compared with participants who did not develop dementia.
Cardiovascular biomarkers may help identify patients with subclinical cerebral injury, according to research published online ahead of print May 9 in Stroke. A total of 1,920 subjects received a brain MRI and had their levels of N-terminal brain natriuretic peptide (NT-proBNP) and cardiac troponin T (hs-cTnT) measured. Of the total group, 1,112 had a follow-up MRI between nine and 13 years later. Individuals with the highest NT-proBNP levels had significantly more silent brain infarcts and white matter lesions on the baseline MRI and more incident silent brain infarcts and white matter lesion progression on the follow-up MRI. Individuals with the highest hs-cTnT levels had more silent brain infarcts and white matter lesions on the initial MRI and more white matter lesion progression on the follow-up MRI.
