New and Noteworthy Information—September 2014
In patients who are hospitalized for surgery, perioperative atrial fibrillation is associated with an increased long-term risk of ischemic stroke, according to a study published in the August 13 issue of JAMA. Researchers studied 1,729,360 patients hospitalized for surgery between 2007 and 2011. Perioperative atrial fibrillation was documented in 24,711 patients (1.43%) during the index hospitalization. After discharge, 13,952 patients (0.81%) had an ischemic stroke. One year after hospitalization for noncardiac surgery, cumulative rates of stroke were 1.47% in patients with perioperative atrial fibrillation and 0.36% in people without atrial fibrillation. One year after cardiac surgery, cumulative rates of stroke were 0.99% in patients with perioperative atrial fibrillation and 0.83% in patients without atrial fibrillation. The association with stroke was stronger for perioperative atrial fibrillation and noncardiac surgery, compared with cardiac surgery.
Approximately one-third of cases of Alzheimer’s disease worldwide might be attributed to potentially modifiable risk factors, investigators reported in the August issue of Lancet Neurology. An international team of researchers used relative risks from existing meta-analyses to estimate the population-attributable risk (PAR) of Alzheimer’s disease worldwide and in the United States, Europe, and the United Kingdom for seven potentially modifiable risk factors. Worldwide, the highest estimated PAR was for low educational attainment. In the US, Europe, and UK the highest estimated PAR was for physical inactivity. Assuming the risk factors’ independence, the combined worldwide PAR for the seven risk factors was 49.4%, which accounts for 16.8 million of the 33.9 million cases. Adjustment for the association between the risk factors decreased the estimate to 28.2%, which equates to 9.6 million cases.
The FDA has approved Belsomra (suvorexant) for adults with insomnia who have difficulty falling and staying asleep. The drug is the first approved orexin receptor antagonist. Orexins are involved in regulating the sleep–wake cycle and play a role in promoting arousal. In clinical trials, Belsomra (Merck; Whitehouse Station, New Jersey) was superior to placebo for reducing sleep latency and improving sleep maintenance, as assessed objectively by polysomnography and subjectively by patient-estimated sleep latency. Belsomra should be taken no more than once per night, within 30 minutes of going to bed, with at least seven hours remaining before the planned time of waking. The total dose should not exceed 20 mg once daily. The most commonly reported adverse reaction among clinical trial participants taking Belsomra was drowsiness.
A clinical diagnosis of Parkinson’s disease identifies patients who will have pathologically confirmed Parkinson’s disease with a sensitivity of 88% and specificity of 68%, researchers reported in the July 29 issue of Neurology. Investigators analyzed data from an aging study to determine the predictive value of clinical diagnosis of Parkinson’s disease using two diagnostic confidence levels: possible and probable Parkinson’s disease. Approximately 26% of patients diagnosed with possible Parkinson’s disease were neuropathologically confirmed as having Parkinson’s disease; 82% of patients diagnosed with probable Parkinson’s disease were confirmed as having Parkinson’s disease. Researchers calculated a 26% accuracy rate for clinical diagnosis of Parkinson’s disease in untreated or not clearly responsive subjects, a 53% accuracy rate in early Parkinson’s disease responsive to medication (less than five year’s duration), and a greater than 85% diagnostic accuracy rate for longer duration, medication-responsive Parkinson’s disease.
Depressive symptoms in old age are associated with cognitive decline that is independent of dementia, according to a study published in the August 19 issue of Neurology. Investigators monitored 1,764 participants with an average age of 77 who had no thinking or memory problems at the start of the study. Participants were screened every year for symptoms of depression and were evaluated for their memory and thinking skills for a mean of 7.8 years. A total of 922 (52%) participants developed mild cognitive impairment, and 315 (18%) developed dementia. Overall, having a higher level of depression symptoms was associated with more rapid decline in thinking and memory skills, which accounted for 4.4% of the difference in decline that could not be attributed to the level of damage in the brain.
Researchers may have found a potential genetic link between epilepsy and neurodegenerative disorders, according to a study published in the July 29 Proceedings of the National Academy of Sciences. The investigators observed that seizure-prone prickle mutant flies have behavioral defects and electrophysiologic defects similar to those of other fly mutants used to study seizures. Altering the balance of two forms of the prickle gene disrupted neural information flow and caused epilepsy. The researchers also observed that reducing either of two motor proteins responsible for directional movement of vesicles along the tracks of structural proteins in axons could suppress seizures. “This is, to our knowledge, the first direct genetic evidence demonstrating that mutations in the fly version of a known human epilepsy gene produce seizures through altered vesicle transport,” stated the authors.
