Deciphering the factors that influence participation in studies requiring serial lumbar punctures

Introduction: Cerebrospinal fluid biomarkers increasingly inform the causes of dementia and may provide objective markers of disease progression. There is a need to decipher participant and procedural factors that promote participation in studies incorporating longitudinal biomarker measures. Methods: Participant and procedural factors associated with participation in longitudinal biomarker studies were determined in individuals enrolled in studies of memory and aging at the Knight Alzheimer Disease Research Center (Saint Louis, MO, USA). Results: Complications were encountered following 331 of 1484 lumbar punctures (22.3%; LPs), affecting 280 of 929 participants (30.1%); in >95% complications were minor. Three hundred fifteen of 679 eligible participants (46.4%) completed multiple LPs. Younger age (odds ratio [OR] 2.08 per decade [95% confidence interval (CI) 1.61–2.94]), normal cognition (OR 21.4 [2.85–160.1]), and the absence of heart disease (OR 2.0 [1.01–3.85]) or seizures at study entry identified participants with increased odds of completing three or more LPs. Discussion: Factors influencing participation may be leveraged to improve recruitment and retention within observational and therapeutic studies requiring serial LPs.