Cognitive impairment and sedentary behavior predict health-related attrition in a prospective longitudinal Parkinson's disease study

In Parkinson's disease (PD), the high burden of motor and non-motor symptoms, such as cognitive impairment or falls, is associated with rapid disease progression and mortality. This is often reflected by an increased drop-out rate of PD patients in longitudinal studies. Active physical behavior can impact the disease course beneficially and has an overall positive effect on health. Contrarily, sedentary behavior is associated with cognitive impairment in PD. The aim of this study was to investigate whether sedentary physical behavior assessed in the home environment and cognitive impairment can predict health-related study attrition due to sickness and death in PD. Data of 45 PD patients, longitudinally assessed, were analyzed. Of those, 20 patients completed six yearly visits, 16 dropped out due to sickness or death, and nine for other reasons. All patients wore a mobile device to assess physical behavior and completed cognitive testing. Logistic regression revealed global cognition was the primary predictor for health-related drop-out in varying models (p ≤ .04). In the survival analysis, cognitive impairment (p = .005) and longer sedentary mean bout length (p = .02) were associated with drop-out due to sickness and death. The occurrence of health-related study drop-out or death was highest in patients with both impaired cognition and longer sedentary bouts. Cognition was the primary predictor for study drop-out due to sickness and death. However, it seems that sedentary behavior might have a potential negative influence on PD patients’ health, especially those with cognitive impairment. •Attrition is a problem in longitudinal PD studies due to increase in symptom burden over time.•Cognition is the primary predictor for study attrition due to sickness and death in PD.•Sedentary behavior is also related to patient’s health related attrition rate within five years.•Cognitive status and sedentary behavior independently affect PD patients’ well-being and mortality.