September 14, 2014
A Study published on-line September 9th in the British Medical Journal is getting a lot of response from healthcare blogs, print media, and other sources such as Medscape. The Canadian case-controlled study set out to investigate the relationship between the risk of Alzheimer’s disease (AD) in older adults and exposure to benzodiazepines (BZNs) five years prior to first diagnosis of AD. Researchers used a retrospective administrative claims database (prescription drug events).
Using a formula to normalize the benzodiazepine exposure in the participants’ claims data, the authors reported that those who took an equivalent of daily doses for three to six months over a five year period were about 32% more likely to develop Alzheimer’s than those case controlled patients who took no study medications. Those patients who took daily doses for more than six months were 84% more likely to develop Alzheimer’s disease.
The potential for adverse medication events (falls, cognitive impairment and decline, impaired activities of daily living) as a result of use of BNZs by older adults is well documented, and addressed previously in this blog (http://actualmeds.com/blog-2/). While the authors stated an objective to study relationships or possible causality with Alzheimer’s disease, the lead author herself has stated “The nature of the link (causal or not) is still not definitive, but these conclusions reinforce the suspicion of a possible direct link.” The authors also note that a study limitation exists due to the nature of the “use of claims databases without direct access to patients.” Dr. Gisele Wolf-Kline, who is director of geriatric education for the North Shore-LIJ Health System in New Hyde Park, N.Y., stated in review of the study “The study was only able to find an association between the drugs and Alzheimer’s risk. One reason is that the findings are based on prescription records [only]. We know the drugs were prescribed, but we don’t know how often people took them, or if they took them at all.”
Our thought is, causal or not, the association between benzodiazepine use and risk of Alzheimer’s disease seems to be dose related and progressive based on time of exposure. We also note that the authors show NO increased risk for older adults who had less than one month exposure for insomnia use, and three months exposure for anxiety. In any event, to accurately determine a patient’s risk, it is imperative that a patient interview be completed to determine a patient’s actual exposure to BZNs, and not rely on formulas and/or prescriptions claims data. Such algorithms can assist us in knowing where to look, but the patient’s own actual medication use must be characterized and is a critical part of risk assessment.
Joseph Gruber RPh, CGP, FASCP Chief Clinical Officer, ActualMeds Corporation. @jgactualmeds