Estimating cumulative live-birth rates after IVF treatment with Kaplan-Meier and competing risk methods

OBJECTIVE(S): 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. STUDY DESIGN: 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. CONCLUSION(S): 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.