Risk Factors of Caregiver Burden Evolution, for Patients With Subjective Cognitive Decline or Neurocognitive Disorders: A Longitudinal Analysis

Abstract

Background/objectives: The identification of factors used to predict caregiver burden may help preventive care. This study aimed to assess the relationship between evolution of patients with subjective cognitive decline (SCD) or progressive neurocognitive disorder (NCD) and evolution of caregiver burden.

Design: Observational, longitudinal study.

Setting: The study was conducted in the Clinical and Research Memory Center of the University Hospital of Lyon (France), between the November 1, 2011 and the June 30, 2014, with a maximum follow-up of 30 months.

Participants: The study population included outpatients with SCD or NCD at all stages, and their informal caregiver.

Measurements: The caregiver burden was assessed during 2 visits of the patients and their caregiver, with the short version of the Zarit Burden Inventory (ZBI). Functional, cognitive performance, and behavioral and psychological symptoms were measured twice, concomitantly with the ZBI, using the Instrumental Activities of Daily Living (IADL) scale, the Mini-Mental State Examination (MMSE), and the Neuropsychiatric Inventory (NPI), respectively. Etiology and stage of the cognitive impairment were collected.

Results: The population study included 222 patients (mean age at inclusion: 80 years old, 62.9% females), with an average follow-up 12.6 ± 6 months. Proportion of patients with major NCD at the second visit (62.2%) increased compared with inclusion (50.0%). MMSE and IADL decreased between the 2 visits (P < .001), whereas ZBI increased (mean ZBI: 3.2 ± 2 at baseline, mean ZBI: 3.8 ± 2 at follow-up, P < .001). In unadjusted analyses, ZBI tended to be higher for patients whose MMSE decreased of at least 3 points between the visits. ZBI increased over time when IADL decreased (P value for within-patient effect <.001), while it remained stable when the IADL increased. ZBI increased when NPI increased. After mutual adjustment for change of MMSE, IADL, NPI, and etiologies, increase of ZBI over time remained significant when MMSE decreased at least 3 points between baseline and follow-up, when IADL decreased, and when NPI increased of at least 4 points.

Conclusions: In a study population of patients with SCD or NCD at all stages, concomitant decrease of cognitive performance, increase of functional impairment, and increase neuropsychiatric symptoms over time were independently associated with increased caregiver burden. The identification of risk factors associated with an increased caregiver burden over time may allow a better evaluation of the impact of specific interventions on cognitive, behavioral, and functional dimensions of NCD on caregivers.

Trial registration: ClinicalTrials.govNCT02825732.

Keywords: Alzheimer disease or related disorder; Caregiver burden; behavioral disorders; cognitive impairment; dependency; longitudinal study; risk factors.