By Kurt Ullman
Nursing home residents with dementia face a significantly increased risk of injurious falls if they are taking selective serotonin reuptake inhibitors (SSRIs), according to a Dutch retrospective study.
There was nearly a three-fold increase in injurious falls seen in patients on any type of antidepressant medication, reported Tischa J.M. van der Cammen, MD, PhD, and colleagues from the Erasmus University Medical Center in Rotterdam, the Netherlands. When subgroups of antidepressants were analyzed, only SSRIs presented a significant risk of injurious falls.
The risk of fall increased significantly at 0.25 defined daily dose of an SSRI (31%) and again at 0.50 defined daily dose (73%). The risk jumped by 198% at one defined daily dose (HR 2.98, 95% CI 1.94 to 4.57), according to the study in the British Journal of Clinical Pharmacology. The risk increased further in combination with a hypnotic or sedative, the authors said.
Patients treated with SSRIs are at increased risk for falls, but among those with dementia, the risk of injurious falls by treatment dose has not been established. The researchers wanted to know if there was a dose-response relationship between SSRI use and falls in their study cohort.
Drug use and falls were recorded among 248 nursing home residents with dementia. The time period addressed was between Jan. 1, 2006 and Jan. 1, 2008. Daily drug use for every patient was abstracted from the home’s prescription database. Information on falls and any subsequent injuries came from a standardized incident reporting system. There were 85,074 person-days in the resulting data set.
All residents met the criteria for a dementia diagnosis from the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Severity of dementia was defined as either stage 5 or stage 6 on the Global Deterioration Scale based on regular treatment team assessments.
Drugs were coded according to their Anatomical Therapeutic Chemical classification. According to the World Health Organization, the defined daily dose is the average dose of drug taken for the main indication.
In the broader analysis, significant dose-response relationships were seen in the use of sedatives or hypnotics (HR 2.55, 95% CI 10.03 to 6.30) and antidepressants in general (HR 2.97, 95% CI 1.95 to 4.53). When the authors took a closer look at the subgroups of antidepressants, only the relationship between falls and SSRIs reached significance (HR 2.98, 95% CI 1.94 to 4.57).
The study had some limitations. The use of injurious falls, rather than falls in general, may have meant that patients with depression were more likely to have their falls recorded as injurious. They also were more likely to be taking an SSRI, which might have led to an overestimation of the results.
Confounding by indication was another possible limitation in the study as the underlying depression by itself may have predisposed people to falls. In addition, neuropsychiatric symptoms and behavioral disturbances may lead to an increased fall risk and/or result in higher drug doses. Also, the presence of SSRIs may have caused pharmacokinetic inhibition of the metabolism of other co-prescribed drugs.
“The main finding of the study in nursing home residents with dementia is that there is a dose-response relationship between the use of SSRIs and a fall with subsequent injury,” wrote the authors. “The risk of an injurious fall increased with increasing doses of SSRIs.”
Nonetheless, the results were in line with previous studies demonstrating a link between use of SSRIs and injurious falls. The current study offers new information on this risk in a mixed nursing home population, the authors said. “To the best of our knowledge, ours is the first study which assessed the dose-response relationship between SSRIs and injurious fall risk in nursing home residents with dementia,” they wrote.