Dose–response relationship between selective serotonin re‐uptake inhibitors and injurious falls: a study in nursing home residents with dementia

Abstract

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT• Patients treated with selective serotonin re‐uptake inhibitors (SSRIs) have been shown to have an increased risk of falling. In nursing homes, many patients with dementia are given SSRIs as a treatment for depression. In this group, however, the possible risk of injurious falls by treatment dosage is not known.WHAT THIS STUDY ADDS• Even at low doses, SSRIs are associated with increased risk of an injurious fall in nursing home residents with dementia. The risk increases with higher doses, with a three‐fold increased risk at 1.00 Defined Daily Dose. The combination of a SSRI with a hypnotic or sedative increases the risk even further.AIMThe contribution of selective serotonin re‐uptake inhibitors (SSRIs) to injurious fall risk in patients with dementia has not been quantified precisely until now. Our objective was to determine whether a dose–response relationship exists for the use of SSRIs and injurious falls in a population of nursing home residents with dementia.METHODSDaily drug use and daily falls were recorded in 248 nursing home residents with dementia from 1 January 2006 until 1 January 2008. For each resident and for each day of the study period, data on drug use were abstracted from the prescription database, and information on falls and subsequent injuries was retrieved from a standardized incident report system, resulting in a dataset of 85 074 person‐days.RESULTSWe found a significant dose–response relationship between injurious falls and the use of SSRIs. The risk of an injurious fall increased significantly with 31% at 0.25 of the Defined Daily Dose (DDD) of a SSRI, 73% at 0.50 DDD, and 198% at 1.00 DDD (Hazard ratio = 2.98; 95% confidence interval 1.94, 4.57). The risk increased further in combination with a hypnotic or sedative.CONCLUSIONSEven at low doses, SSRIs are associated with increased risk of an injurious fall in nursing home residents with dementia. Higher doses increase the risk further with a three‐fold risk at 1.00 DDD. New treatment protocols might be needed that take into account the dose–response relationship between SSRIs and injurious falls.