Reaching the hard to reach: a protocol for enrolling individuals with Parkinsonism who lack capacity to consent in the PRIME-UK Cross-sectional Study

Introduction: Many people with parkinsonism (PwP) develop cognitive impairment (CI) as the condition progresses, contributing to clinical complexity and increasing care needs. Such individuals are less likely to be recruited into research, thereby providing an overly optimistic clinical picture. This study aims to describe the healthcare needs of a broad range of PwP. We have developed a method to include individuals with CI and dementia, who are typically excluded.

Methods: PwP will be sent a study invitation pack and non-responders will be followed up by telephone. If a patient lacks capacity to consent, a personal consultee will be sought to advise on the patient’s wishes and to sign a consultee declaration, if appropriate. They will then provide information about the PwP by completing a ‘‘representative’’ questionnaire so that they are not excluded. This booklet has been designed for people with CI and includes assessment of nutritional risk, wellbeing, neuropsychiatric symptoms etc. using questionnaires validated for proxy completion where possible.

Results: We will compare our results of various health outcomes with and without inclusion of the representative data to show the degree of selection bias that occurs if efforts are not made to be inclusive of all PwP.

Conclusions: Existing cohorts have generally focused on patients with idiopathic Parkinson’s Disease and typically exclude individuals with severe comorbid illness or CI precluding consent. Recruiting PwP who are additionally living with frailty, multimorbidity and CI will allow us to describe a more representative population and address this area of unmet need.