Recent hospitalization and risk of antidepressant initiation in people with Parkinson's disease

People with Parkinson's disease (PD) are more likely to be hospitalized and initiate antidepressant use compared to people without PD. It is not known if hospitalization increases the risk of antidepressant initiation. We studied whether a recent hospitalization associates with antidepressant initiation in people with PD.

A nested case-control study within the nationwide register-based FINPARK cohort which includes community-dwelling Finnish residents diagnosed with PD between years 1996 and 2015 (N = 22,189) was conducted. Initiation of antidepressant use after PD diagnosis was identified from Prescription Register with 1-year washout period (cases). One matched non-initiator control for each case was identified (N = 5492 age, sex, and time since PD diagnosis-matched case-control pairs). Hospitalizations within the 14 day-period preceding the antidepressant initiation were identified from the Care Register for Health Care.

The mean age at antidepressant initiation was 73.5 years with median time since PD diagnosis 2.9 years. Selective serotonin reuptake inhibitors (48.1%) and mirtazapine (35.7%) were the most commonly initiated antidepressants. Recent hospitalization was more common among antidepressant initiators than non-initiators (48.3 and 14.3%, respectively) and was associated with antidepressant initiation also after adjusting for comorbidities and use of medications during the washout (adjusted OR, 95% CI 5.85, 5.20-6.59). The initiators also had longer hospitalizations than non-initiators. PD was the most common main discharge diagnosis among both initiators (54.6%) and non-initiators (28.8%). Discharge diagnoses of mental and behavioral disorders and dementia were more common among initiators.

Hospitalisation is an opportunity to identify and assess depressive symptoms, sleep disorders and pain, which may partially explain the association. Alternatively, the indication for antidepressant initiation may have led to hospitalisation, or hospitalisation to aggravation of, e.g., neuropsychiatric symptoms leading to antidepressant initiation.