Screening and enrolling subjects in a randomized clinical trial involving implant dentures.
OBJECTIVE
When planning and budgeting for a clinical trial, researchers have few references to help them estimate how many volunteers will need to be screened, how long the screening process may take, and how much it may cost to enroll sufficient qualified subjects. The purpose of this study was to analyze the time and costs involved in recruiting, screening, and enrolling subjects for a randomized clinical trial examining patient satisfaction with mandibular dentures retained by 1 or 2 implants.


METHODS
Data collected included age and sex of volunteers, recruiting sources, length of time and costs of recruiting and screening volunteers, and reasons for inclusion or exclusion. Results were analyzed using Pearson chi-square tests.


RESULTS
We estimated that we would need to screen 180 volunteers over a period of 4 years at an estimated total cost of CAN$47,664.00 to enroll 86 subjects. Instead, we had to screen 220 volunteers at a direct cost of $63,324.81. We excluded 28% of volunteers, while 32% declined participation and 40% agreed to participate in the study. Volunteers were most commonly excluded because of technical problems with their existing dentures, while they were most likely to decline participation because of perceived surgical risks with implants. Those who agreed to participate most commonly cited anticipation of a more secure mandibular denture as their reason for enrolling.


CONCLUSIONS
We had to screen more volunteers at a higher cost than anticipated, with only 40% of those screened meeting inclusion criteria and agreeing to participate in the trial.
Walton
Joanne N
JN
Department of Oral Health Sciences, University of British Columbia, Vancouver, British Columbia, Canada. jnwalton@interchange.ubc.ca
MacEntee
Michael I
MI
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D003365:Costs and Cost Analysis; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D003781:Denture Retention; D003826:Denture, Complete, Lower; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010342:Patient Acceptance of Health Care; D017060:Patient Satisfaction; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic / Q000191:economics / Q000379:methods*; D045808:Refusal to Participate; D012107:Research Design; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors
D015921:Dental Implants