The interrelationship of frailty, multimorbidity and disability in Parkinson’s disease: PRIME-UK cross-sectional study

Background:
The prevalence of Parkinson’s disease rises with age and so patients may also be living with multimorbidity, two or more long-term conditions, and frailty, a loss of physiological reserve. However, these individuals are typically under-represented in clinical research. The aim was to describe the prevalence and interrelationship of frailty, multimorbidity, disability, sarcopenia and polypharmacy in a representative sample of people with parkinsonism recruited to the PRIME-UK cross-sectional study.

Methods:
In this single-centre cross-sectional study of people with parkinsonism, we supported the inclusion of typically under-represented groups including those with impaired capacity to consent to the research. Participants, or their representative, completed questionnaires including self-reported comorbidities, medications, a sarcopenia screening tool and measures of frailty and disability. Venn diagrams were used to show the overlap between these domains and a hierarchical cluster analysis was performed to explore clustering.

Results:
Only 78 (16.8%) were categorised as neither frail nor multimorbid nor disabled. Almost all patients living with frailty were additionally living with disability and/or multimorbidity. It was uncommon to have multimorbidity and frailty without disability. Only 6 (1.3%) had frailty without probable sarcopenia. Individuals clustered into three groups based on co-occurrence of some or all of these five domains.

Conclusions:
Amongst a representative sample of people with parkinsonism, there was a high frequency and co-occurrence of pre-frailty/frailty, sarcopenia, multimorbidity, polypharmacy and disability. This has implications for the structuring of health services for people with parkinsonism. There may also be opportunities to intervene to stop or slow the trajectory towards disability.