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Table 2 Recruitment flow from EPAD Registry by recruitment setting

From: Prescreening for European Prevention of Alzheimer Dementia (EPAD) trial-ready cohort: impact of AD risk factors and recruitment settings

Toulouse RegistryALFA StudyGeneration 
 SettingMemory clinicIn-person research cohortPopulation-basedOnline research cohort 
Step 1Selection by PREPAD tool16961819472753009
Step 2Not eligible based database check11347155414
 • Exclusion criterion10110129150
 • Other1237026264
 Number selected for step 3 (% from step 1)158 (93%)271 (44%)1946 (100%)220 (80%)2595 (86%)
Step 3Not eligible after contacting participant6511918791192182
 • No interest642417883349
 • No response to letterNANA1470NA1470
 • Exclusion criterion037122473
 • Other15821912290
 Number selected for step 4 (% from step 3)93 (59%)152 (56%)67 (3%)101 (46%)413 (16%)
Step 4EPAD-LCS screening visit701376788362
 Eligible & CSF Aβ1–42 analysed641246175324
 • CSF Aβ1–42 < 1098 pg/mL (positivity)23 (36%)36 (29%)22 (36%)26 (35%)107 (33%)
 Number needed to screen3.
 Number needed to prescreen6.97.588.58.524.3
  1. Legend: in italic the total number of the subset on which percentages are based. Number of individuals unless otherwise specified. CSF cerebrospinal fluid, EPAD-LCS v500 is the currently available data, quality checked at data lock. N = 51 EPAD screening visit details not yet available. N = 5 CSF results missing. N = 32 screen failure: 11× other disease/incidental findings/CDR > =1, 18× procedures not possible, 3× investigator decision/no reason provided/no contact possible. Number needed to screen = N CSF Aβ1–42 positive in step 4 / N eligible and CSF Aβ1–42 analysed in step 4, while the number needed to prescreen = N CSF Aβ1–42 positive in step 4/ N selected for step 3