Association of Caregiver Depression Risk With Patient Outcomes in Parkinson Disease.

Importance: Caregivers are integral to Parkinson disease (PD) care, but little information exists regarding how caregivers impact patient outcomes. Objective: To assess the association between caregivers reporting depression symptoms and patient quality of life (QOL), emergency department (ED) visits, and hospitalizations. Design, Setting, and Participants: This retrospective cohort study was conducted at 15 Parkinson's Foundation Centers of Excellence within the US. The Parkinson's Foundation Parkinson Outcomes Project registry was used to collect baseline data from January 1, 2016, to December 31, 2018, with subsequent annual study visits through July 31, 2020. Data were analyzed from August 5, 2020, to June 9, 2023. A convenience sample of 454 patients with PD and their caregivers was recruited during routine clinical visits with movement disorder specialists. Patients with a physician diagnosis of idiopathic PD who lived at home and had 1 or more follow-up study visits were included. Exposure: Caregiver depression symptoms using the Center for Epidemiologic Studies Depression Scale. Main Outcomes and Measures: Patient health-related QOL (measured by the 39-item Parkinson Disease Questionnaire), number of annual ED visits, and number of annual hospitalizations were measured. The independent association between caregivers reporting depression symptoms and patient outcomes was assessed using linear mixed-effects and Poisson regression models. The a priori hypotheses were that a greater number of depression symptoms reported via the Center for Epidemiologic Studies Depression Scale would be associated with worse patient QOL and a greater number of ED visits and hospitalizations. Results: Among 454 patient-caregiver dyads (patients: mean [SD] age, 67.3 [8.4] years; 320 men [70.5%]; caregivers: mean [SD] age, 65.9 [8.7] years; 326 women [71.8%]), the mean (SD) follow-up was 2.0 (1.4) study visits. Greater depression symptoms among caregivers were associated with worse patient QOL as measured by the Parkinson Disease Questionnaire (mean [SD] score, 33.78 [17.71], on a scale of 0-100, with higher scores indicating worse QOL, among patients with caregivers who had depression symptoms vs 24.50 [14.19] among patients with caregivers who did not have depression symptoms; β = 0.43; 95% CI, 0.28-0.58; P < .001) and more annual ED visits (β = 0.02; 95% CI, 0 to 0.04; P = .03) but not more hospitalizations (β = 0.02; 95% CI, -0.01 to 0.03; P = .10). Conclusions and Relevance: In this cohort study, patients with PD who had caregivers at higher risk of depression were more likely to have worse QOL and higher ED use than patients who had caregivers not at higher risk of depression. Additional caregiving resources and interventions to reduce caregiver depression symptoms could potentially improve patient outcomes.