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Table 3 Association between baseline factors and failure to complete study

From: Participant characteristics associated with withdrawal from a large randomized trial of spermicide effectiveness

  Total Did not complete study Relative Risk (95% confidence interval)
  N n %  
Age     
   ≤25 years 660 317 48.0 1.29 (1.15 – 1.45)
   > 25 years 854 318 37.2 1
Relationship     
   single not living with partner 522 247 47.3 1.21 (1.07 – 1.36)
   married or living with partner 992 388 39.1 1
Living children     
   None 639 288 45.1 1.14 (1.0 1 – 1.28)
   Any 875 347 39.7 1
Baseline coital frequency     
   ≥8 acts per month 862 389 45.1 1.21 (1.07 – 1.37)
   ≤7 acts per month 640 239 37.3 1
Geographic region of US     
   West 424 215 50.7 1.28 (1.12 – 1.46)
   South 460 170 37.0 0.93 (0.80 – 1.09)
   Northeast 630 250 39.7 1
Center type     
   university* 1069 476 44.5 1.25 (1.08 – 1.44)
   other 445 159 35.7 1
Recruitment rate at study site     
   ≤4 per month 640 301 47.0 1.23 (1.09 – 1.38)
   > 4 per month 874 334 38.2 1
Reimbursement rate     
   ≤$200 462 232 50.2 1.31 (1.16 – 1.47)
   >$200 1052 403 38.3 1
Participation in colposcopy study     
   No 1381 590 42.7 1.26 (0.99, 1.61)
   Yes 133 45 33.8 1
  1. *University centers were defined as those at which participants were seen in a primary university clinic setting. These included: University of Alabama at Birmingham, Birmingham, AL; University of Tennessee at Memphis, Memphis, TN; The University of Texas Health Science Center at San Antonio, San Antonio, TX; Baylor College of Medicine, Houston, TX; Medical University of South Carolina, Charleston, SC; University of Pittsburgh and the Magee-Womens Research Institute, Pittsburgh, PA; University of Pennsylvania Medical Center, Philadelphia, PA; University of Arizona Health Sciences Center, Tucson, AZ; NYU School of Medicine, New York, NY. Other centers included: Johns Hopkins Medical Services Corporation, Baltimore, MD; Vermont Women's Choice Program of Planned Parenthood, Burlington, VT; Eastern Virginia Medical School, Norfolk, VA; Minneapolis Medical Research Foundation, Minneapolis, MN; Planned Parenthood of Central and Northern Arizona, Phoenix, AZ
  2. Although this confidence limit includes 1, the p-value for the association between this factor and early withdrawal was 0.047.