title: Estimating cumulative live-birth rates after IVF treatment with Kaplan-Meier and competing risk methods.
abstract: OBJECTIVE
  To explore the use of competing risk (CR) as compared to the commonly used Kaplan-Meier (KM) methodology in estimating the cumulative live-birth rate (CLBR) after IVF Treatment in a context of high dropout rates and informative censoring.
  
  
  METHODS
  We compare the KM and CR methodologies for estimating 2-year CLBR in a retrospective cohort of 2779 patients undergoing 5002 embryo transfers over a period of 9 years, from 2000 to 2008, at KKIVF Centre.
  
  
  RESULTS
  We observed a total of 1105 LB (39.8%), and a dropout rate of 44.2% (1228 patients). The overall CLBR is lower with CR compared with KM method (39% vs 52%) after up to nine embryo-transfer cycles over a period of two years. The highest CLBR was achieved for ovulation disorders (57% vs 49%, KM vs CR) followed by male factors (54% vs 43%, KM vs CR), with poorer outcomes from patients with decreased ovarian reserve (37% vs 16%, KM vs CR) and endometriosis (36% vs 25%, KM vs CR). As dropouts in our cohort are generally older and more likely to have poorer ovarian reserves, the CR method, which accounted for these dropouts, is likely to give more meaningful estimation of IVF success rates.
  
  
  CONCLUSIONS
  The CR method should be considered as a useful alternative in deriving CLBR for IVF treatment where dropout rates are high and when informative censoring is involved.
authors.affiliation: Department of Reproductive Medicine, KK Women's and Children's Hospital, Singapore 229899, Singapore. Electronic address: veraxel3@yahoo.fr.
authors.forename: Veronique
authors.initials: V
authors.lastname: Viardot-Foucault
authors.affiliation: Saw Swee Hock School of Public Health, National University of Singapore and National University Health System, Singapore 117597, Singapore; Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore 119228, Singapore; Investigational Medicine Unit, National University Health System, Singapore 119074, Singapore. Electronic address: bee_choo_tai@nuhs.edu.sg.
authors.forename: Bee Choo
authors.initials: BC
authors.lastname: Tai
authors.affiliation: Investigational Medicine Unit, National University Health System, Singapore 119074, Singapore.
authors.forename: Zhao Jin
authors.initials: ZJ
authors.lastname: Chen
authors.affiliation: Health Promotion Board, National Registry of Diseases Office, Singapore 168937, Singapore.
authors.forename: Gek Hsiang
authors.initials: GH
authors.lastname: Lim
authors.affiliation: Department of Reproductive Medicine, KK Women's and Children's Hospital, Singapore 229899, Singapore; Thomson Fertility Centre, Novena Specialist Center, Singapore 307470, Singapore.
authors.forename: Seong Feei
authors.initials: SF
authors.lastname: Loh
authors.affiliation: Department of Reproductive Medicine, KK Women's and Children's Hospital, Singapore 229899, Singapore.
authors.forename: Heng Hao
authors.initials: HH
authors.lastname: Tan
authors.affiliation: Department of Reproductive Medicine, KK Women's and Children's Hospital, Singapore 229899, Singapore.
authors.forename: Sadhana
authors.initials: S
authors.lastname: Nadarajah
authors.affiliation: Department of Reproductive Medicine, KK Women's and Children's Hospital, Singapore 229899, Singapore; Cancer and Stem Cell Biology Program, Duke-NUS Graduate Medical School, National University of Singapore, Singapore 169857, Singapore; Experimental Fetal Medicine Group, Department of Obstetrics and Gynecology, National University of Singapore, Singapore 119228, Singapore.
authors.forename: Jerry Kok Yen
authors.initials: JK
authors.lastname: Chan
mesh_terms: D000328:Adult; D004624:Embryo Transfer / Q000706:statistics & numerical data; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D006801:Humans; D007247:Infertility, Female / Q000628:therapy; D007248:Infertility, Male / Q000628:therapy; D053208:Kaplan-Meier Estimate; D050498:Live Birth; D008297:Male; D010352:Patient Dropouts / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods
keywords: Competing risk; Cumulative live-birth rates; In vitro fertilisation; Kaplan–Meier