The effects of medical comorbidity, cognition, and age on patient-reported outcomes in Parkinson's disease

The purpose of this cross-sectional study was to compare the independent contributions of medical comorbidity, cognition, and age on patient-reported outcomes in Parkinson's disease (PD). 572 PD patients completed the Patient-Reported Outcome Measurement Information System (PROMIS®)-29 v2.0 Profile (physical function, anxiety, depression, fatigue, sleep disturbance, satisfaction with participation in social roles, pain interference) and PROMIS Global Health (mental health and physical health) scales. Comorbidity was measured with the Cumulative Illness Rating Scale–Geriatric (CIRS-G) and cognition with the Montreal Cognitive Assessment (MoCA). Multiple regression models examined the 9 PROMIS measures as predicted by comorbidity, cognition, and age, adjusting for demographic and clinical characteristics (UPDRS and disease duration). Comorbidity was associated with poorer outcomes in all nine PROMIS domains. Cognition was associated with two of nine domains: physical function and anxiety. Age was associated with five domains: anxiety, depression, sleep disturbance, satisfaction with participation in social roles, and global mental health. Comorbidity showed greater effects on all nine domains than cognition or age (higher standardized beta coefficients). Medical comorbidity, cognition, and age have different impacts on patient-reported outcomes in PD. Medical comorbidity has a greater impact than either cognition or age on a range of patient-reported physical and mental health domains. Medical comorbidity is an important contributor to the patient's perspective of their physical and mental health. •Comorbidity, cognition, and age have different impacts on nine domains of patient-reported health outcomes.•Higher comorbidity was associated with poorer patient-reported health outcomes, even when controlling for disease severity.•Comorbidity had stronger effects than cognition and age on all of nine patient-reported health outcomes.•We suggest an increased awareness of the impact of comorbidity among PD patients during clinical visits.