A new study, published in the International Journal of Geriatric Psychiatry, examines whether antidepressant use may increase the risk of hip fractures in older adults with and without Alzheimer’s disease. The cohort study conducted in Finland, with data from over 150,000 individuals, finds evidence that antidepressant use increases the risk of hip fractures in older adults, especially during the first month of use.
“We found two-three times higher risk for hip fracture during antidepressant use compared with nonuse among older persons,” write the researchers, led by Sanna Torvinen-Kiiskinen, a doctoral student at the University of Eastern Finland.
Antidepressant medication is commonly prescribed to older adults. This is particularly true for individuals diagnosed with Alzheimer’s disease, who are prescribed antidepressants three times as often as other adults. Many researchers have raised significant concerns about the side effects of antidepressants for all ages (e.g., sexual side effects, link to diabetes, increased agitation and violence).
These concerns may be even more significant for older adults as the authors note, “due to age-related changes in pharmacokinetics and pharmacodynamics, use of antidepressants is associated with adverse drug events among older persons.” These adverse events include gastrointestinal bleeding, stroke, and low sodium levels. Antipsychotic medication has also been linked to increased risk of death in individuals with Alzheimer’s disease.
In older adults, antidepressant use has been connected to increased risk of falls and fractures. “Hip fractures are one of the most serious fractures and frequently lead to persistent mobility limitations and institutionalization especially among persons with dementia,” write the researchers.
In the current study, the researchers aim “to investigate whether antidepressant use is associated with an increased risk of hip fracture among community-dwelling persons with and without AD [Alzheimer’s disease], and to compare the risk according to duration of use and groups of antidepressants.” The researchers used data from the Medication Use and Alzheimer’s Disease (MEDALZ) Cohort Study, which includes all community-dwelling individuals (i.e., older adults not living in nursing homes) in Finland from 2005-2011. The researchers matched 50,491 individuals diagnosed with Alzheimer’s disease with two older adults not diagnosed with Alzheimer’s (n = 100,982).
The researchers adjusted their analyses to account for confounding factors such as history of other medical or psychiatric conditions and use of other psychotropic medications. They report their results in terms of hazard ratios (HRs), which describe how often an event occurs in one group compared to another.
Most participants were women (62%) with an average age of 80 years old. The researchers find, “Antidepressant was initiated by 22.4% (N = 11,329) of persons with AD and 9.9% (N = 10,001) of persons without AD.”
The authors report that 5.2% of individuals diagnosed with Alzheimer’s disease and 2.9% of those without an Alzheimer’s diagnosis experienced a hip fracture during the 4-year follow-up period. Results also show that antidepressant use is linked to higher risk of hip fracture both for older individuals diagnosed with Alzheimer’s Disease (HR = 1.61) and people who are not diagnosed with Alzheimer’s (HR = 2.71).
The risk of hip fracture was highest during the first month of taking antidepressants (with Alzheimer’s disease, HR = 3.30; without Alzheimer’s disease, HR = 3.92), but remained high at the 4-year follow-up. Risk for hip fracture remained high for all classes of drugs studied: SSRIs, mirtazapine, and especially SNRIs. The authors suggest that antidepressant side effects such as sedation, low blood pressure, confusion, and decrease in bone mineral density may help explain the increase risk of falls and fractures.
The finding that individuals taking antidepressants who are not diagnosed with Alzheimer’s disease have higher risk ratios for hip fractures than individuals diagnosed with Alzheimer’s disease may initially be confusing. However, the authors explain this finding by the fact that individuals with Alzheimer’s disease have higher risk of hip fractures at baseline, emphasizing this population’s vulnerability to hip fractures and the need for prescribers to consider falls as a significant adverse event of antidepressant use for this population.
This study further supports previous evidence that antidepressants are linked to increased risk of falls and fractures in older adults, and especially raises concerns about the vulnerability of individuals diagnosed with Alzheimer’s disease. The authors caution against treatment guidelines that suggest antidepressants as an alternative to other psychotropic medications, since they find no antidepressant group may be safer in terms of hip fractures. The authors conclude, “if the antidepressant treatment is necessary, other risk factors for falling should be carefully considered.”
Torvinen‐Kiiskinen, S., Tolppanen, A.-M., Koponen, M., Tanskanen, A., Tiihonen, J., Hartikainen, S., & Taipale, H. (2017). Antidepressant use and risk of hip fractures among community‐dwelling persons with and without Alzheimer’s disease. International Journal of Geriatric Psychiatry. Advance online publication. doi:10.1002/gps.4667 (Abstract)