To study how long antidepressants initiated after diagnoses of Alzheimer's disease (AD) were used and factors associated with discontinuation of use among persons with Alzheimer's disease (AD). In addition, differences in duration of use between the antidepressants groups were compared.
Register-based Medication use and Alzheimer's disease (MEDALZ) cohort included 70,718 community-dwelling people with AD who were diagnosed during the years 2005-2011. For this study, the new antidepressant users were included after 1-year washout period (N?=?16,501; 68.6% females, mean age 80.9). The duration of antidepressant use was modeled with the PRE2DUP method. Factors associated with treatment discontinuation were assessed with Cox proportional hazard models and included age, gender, comorbid conditions and concomitant medications.
Median duration of the new antidepressant use period was 309 days (IQR 93-830). For selective serotonin reuptake inhibitor (SSRI) use, the median duration was 331 days (IQR 101-829), for mirtazapine 202 days (IQR 52-635), and for serotonin and norepinephrine reuptake inhibitors (SNRIs) 134 days (IQR 37-522). After 1-year follow-up, 40.8% had discontinued antidepressant use, 54.6% after 2 years and 64.1% after 3 years. Factors associated with treatment discontinuation were age over 85, male gender, diabetes, and use of memantine, opioids, and antiepileptics whereas benzodiazepines and related drugs and antipsychotic use were inversely associated with discontinuation.
Antidepressants are used for long-term among people with AD. Need and indication for antidepressant use should be assessed regularly as evidence on their efficacy for behavioral and psychological symptoms of dementia is limited.
Antidepressant use has been associated with an increased risk of falling, but no studies have been conducted on whether antidepressant use is associated with an increased risk of head injuries which often result from falling among older persons. The objective of this study was to investigate the risk of head and brain injuries associated with antidepressant use among community-dwelling persons with Alzheimer's disease.
A matched cohort study was conducted by comparing new antidepressant users (n?=?10,910) with two matched nonusers (n?=?21,820) in the MEDALZ study cohort. The MEDALZ cohort includes all community-dwelling persons newly diagnosed with Alzheimer's disease between 2005 and 2011 in Finland. Incident antidepressant users were identified based on register-based dispensing data from the Prescription register with a 1-year washout period for antidepressant use. Nonusers were matched with users based on age, gender, and time since Alzheimer's disease diagnosis. The outcome events were defined as any head injuries and traumatic brain injuries based on diagnoses in Hospital Discharge and Causes of Death registers. Propensity score adjusted Cox proportional hazard models were utilized. Sensitivity analyses with case-crossover design were conducted. All registers are linkable with unique personal identification numbers assigned for each resident.
Antidepressant use was associated with an increased risk of head injuries (age-adjusted event rate per 100 person-years 2.98 (95% confidence interval (CI) 2.49-3.06) during use and 2.43 (95% CI 2.06-2.35) during nonuse, adjusted hazard ratio (HR) 1.35, 95% CI 1.20-1.52) and traumatic brain injuries (age-adjusted event rate per 100 person-years 1.33 (95% CI 1.13-1.53) during use and 1.10 (95% CI 1.00-1.20) during nonuse, adjusted HR 1.26, 95% CI 1.06-1.50). The risk was highest during the first 30 days of use (HR 1.71, 95% CI 1.10-2.66 for head injuries; HR 2.06, 95% CI 1.12-3.82 for traumatic brain injuries) and remained at an elevated level for head injuries for over 2 years of use. In case-crossover analyses, antidepressant use was consistently associated with a higher risk of head injuries.
Antidepressant use was associated with an increased risk of the most severe outcomes, head and brain injuries, in persons with Alzheimer's disease. Antidepressant use should be carefully considered and the association confirmed in future studies.
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