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Table 1 Referrals and inclusions*

From: Review of the recruitment process for a large investigator-initiated trial in early Parkinson’s disease

Referrals and inclusions Total Northwest Northeast East Southeast Southwest Unknown
Estimated population on 1/1/2012 aged 50–79 in all five regions 5,284,676 1,316,362 945,173 1,295,626 211,983 1,515,531  
Estimated eligible patients during trial 6589 1641 1178 1615 264 1890  
Referred (% estimated eligible) 766 (11.6) 317 (19.3) 103 (8.7) 166 (10.3) 79 (29.9) 100 (5.3) 1
Included patients (% included of referred) 446 (58.2) 190 (59.9) 51 (49.5) 97 (58.4) 47 (59.5) 61 (61.0)  
Not included        
Reason (% of not included patients)
Unknown§ 133 (41.6) 35 (10.9) 20 (6.3) 59 (18.4) 9 (2.8) 9 (2.8) 1 (0.3)
Exclusion criterion 53 (16.6) 24 (7.5) 9 (2.8) 4 (1.3) 8 (2.5) 8 (2.5)  
Too taxing** 41 (12.8) 15 (4.7) 9 (2.8) 2 (0.6) 7 (2.2) 8 (2.5)  
Patient wanted to start with medication** 39 (12.2) 20 (6.3) 8 (2.5) 1 (0.3) 1 (0.3) 9 (2.8)  
Patient did not want medication** 35 (10.9) 24 (7.5) 1 (0.3) 2 (0.6) 3 (0.9) 5 (1.6)  
Afraid of side-effects** 6 (1.9) 3 (0.94) 3 (0.94)     
Patient could not be reached 4 (1.3) 2 (0.6) 1 (0.3)   1 (0.3)   
Research nurse did not receive referral** 2 (0.6)     2 (0.6)   
Participation in other clinical research 2 (0.6) 1 (0.3)    1 (0.3)   
Extended stay outside Netherlands 2 (0.6) 1 (0.3)   1 (0.3)    
Patient not convinced of PD-diagnosis** 1 (0.3) 1 (0.3)      
Only wants to participate if unblinded** 1 (0.3) 1 (0.3)      
Time to contact patient took too long** 1 (0.3)   1 (0.3)     
% of unknown reason relative to number of non-inclusion 41.6% 27.6% 38.5% 85.5% 28.1% 23.1%  
  1. *The Netherlands was divided into five regions from which all regional study procedures were performed by the main study center. These were Academic Medical Center (Northwest), University Medical Center Groningen (Northeast), Radboud University Medical Center (East), Zuyderland Medical Center (Southeast), and Leiden University Medical Center (Southwest)
  2. Source: Demografische kerncijfers per gemeente 2012, ISBN: 978-90-357-2092-3
  3. Source: reference number 9
  4. §Possible partially able to include; a total of 41.6% of not included patients
  5. One patient withdrew from the trial after inclusion but before baseline measurements and randomization and wanted its records to be destroyed
  6. Not possible to include; a total of 19.1% of not included patients
  7. **Patient not convinced to participate, so possibly able to include; a total of 39.4% of not included patients