Predictors of participant retention in infertility treatment trials.
OBJECTIVE
To identify variables associated with retention (or dropout) in infertility clinical trials. Retention of subjects in randomized controlled clinical trials (RCTs) has received considerable attention, but there have been few consistent findings.


METHODS
Secondary analysis of data from RCTs.


METHODS
Academic medical centers.


METHODS
Women with polycystic ovary syndrome (PCOS) or couples with unexplained infertility, aged 18-40 years.


METHODS
This study is not an intervention study, but the patients in the original RCTs were treated with any or combination of metformin, clomiphene citrate (CC), letrozole, and gonadotropins.


METHODS
Successful retention versus dropout during the RCTs.


RESULTS
Race, ethnicity, body mass index (BMI), insurance coverage, history of smoking, and history of alcohol use were significantly associated with retention whether they were considered in bivariate analyses or a multivariable logistic model. Specifically, white race, higher income, having graduate degrees, normal weight, better insurance coverage, nonsmokers, and those who reported current use of alcohol at the start of the trial, had higher retention rates.


CONCLUSIONS
We identified several additive and persistent predictors of retention that can be used to guide the conduct of RCTs and improve the retention rate. Given the limitation of our association analysis, methodologically sound and theoretically grounded research are warranted so that high quality data can be collected to improve our understanding on the causes of dropout.


BACKGROUND
NCT00068861 (PPCOS-I), NCT00719186 (PPCOS-II), and NCT01044862 (AMIGOS).
Department of Obstetrics and Gynecology, First Affiliated Hospital and Heilongjiang University of Chinese Medicine, Harbin, People's Republic of China; Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut.
Hongying
H
Kuang
Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut.
Susan
S
Jin
Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut.
Tracey
T
Thomas
Department of Obstetrics and Gynecology, University of Connecticut School of Medicine, Farmington, Connecticut.
Lawrence
L
Engmann
Department of Obstetrics and Gynecology, University of Oklahoma College of Medicine, Oklahoma City, Oklahoma.
Karl R
KR
Hansen
Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, Pennsylvania.
Christos
C
Coutifaris
Department of Obstetrics and Gynecology, University of Vermont, Burlington, Vermont.
Peter
P
Casson
Department of Obstetrics and Gynecology, Shands Hospital, University of Florida, Gainesville, Florida.
Gregory
G
Christman
Department of Obstetrics and Gynecology, University of Colorado, Aurora, Colorado.
Ruben
R
Alvero
Department of Obstetrics and Gynecology, University of Colorado, Aurora, Colorado.
Nanette
N
Santoro
Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland.
Esther
E
Eisenberg
Department of Obstetrics and Gynecology, Georgia Regents University, Augusta, Georgia.
Michael P
MP
Diamond
Department of Obstetrics and Gynecology, Penn State College of Medicine, Hershey, Pennsylvania.
Richard S
RS
Legro
Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut. Electronic address: Heping.Zhang@yale.edu.
Heping
H
Zhang
D000046:Academic Medical Centers; D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D004359:Drug Therapy, Combination; D005260:Female; D005298:Fertility / Q000187:drug effects*; D005300:Fertility Agents, Female / Q000009:adverse effects / Q000627:therapeutic use*; D006801:Humans; D007247:Infertility, Female / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D010352:Patient Dropouts; D018579:Patient Selection; D011085:Polycystic Ovary Syndrome / Q000150:complications; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D012307:Risk Factors; D016896:Treatment Outcome; D055815:Young Adult
D005300:Fertility Agents, Female
Randomized controlled clinical trial; dropout; logistic regression; retention