Enhancing recruitment of individuals living with frailty, multimorbidity and cognitive impairment to Parkinson's research: experiences from the PRIME-UK cross-sectional study.

Background And Objectives: People with parkinsonism who are older, living in a care home, with frailty, multimorbidity or impaired capacity to consent are under-represented in research, limiting its generalisability. We aimed to evaluate more inclusive recruitment strategies.

Methods: From one UK centre, we invited people with parkinsonism to participate in a cross-sectional study. Postal invitations were followed by telephone reminders and additional support to facilitate participation. Personal consultees provided information on the views regarding research participation of adults with impaired capacity. These approaches were evaluated: (i) using external data from the Parkinson's Real World Impact assesSMent (PRISM) study and Clinical Practice Research Datalink (CPRD), a sample of all cases in UK primary care, and (ii) comparing those recruited with or without intensive engagement.

Results: We approached 1,032 eligible patients, of whom 542 (53%) consented and 477 (46%) returned questionnaires. The gender ratio in PRIME-UK (65% male) closely matched CPRD (61% male), unlike in the PRISM sample (46%). Mean age of PRIME participants was 75.9 (SD 8.5) years, compared to 75.3 (9.5) and 65.4 (8.9) years for CPRD and PRISM, respectively. More intensive engagement enhanced recruitment of women (13.3%; 95% CI 3.8, 22.9%; P = 0.005), care home residents (6.2%; 1.1, 11.2%; P = 0.004), patients diagnosed with atypical parkinsonism (13.7%; 5.4, 19.9%; P < 0.001), and those with a higher frailty score (mean score 0.2, 0.1, 0.2; P < 0.001).

Conclusions: These recruitment strategies resulted in a less biased and more representative sample, with greater inclusion of older people with more complex parkinsonism.