Projecting the clinical benefits and risks of using efavirenz-containing antiretroviral therapy regimens in women of childbearing age.

Objectives: To project the outcomes of using either efavirenz or nevirapine as part of initial antiretroviral therapy (ART) in women of childbearing age in Côte d'Ivoire.

Methods: We used an HIV computer simulation model to project both the mother's survival and the birth defects at 10 years for a cohort of women who started ART with either efavirenz or nevirapine. The primary outcome was the ratio at 10 years of the difference in the number of women alive to the difference in the cumulative number of birth defects in women who started ART with efavirenz compared with nevirapine. In the base case analysis, the birth defect rate was 2.9% on efavirenz and 2.7% on nevirapine. In sensitivity analyses, we varied all inputs across confidence intervals reported in the literature.

Results: In the base case analysis, for a cohort of 100 000 women, the additional number of women alive initiating ART with efavirenz at 10 years was 15 times the additional number of birth defects (women alive: nevirapine 67 969, efavirenz 68 880, difference =  911; birth defects: nevirapine 1128, efavirenz 1187, difference = 59). In sensitivity analysis, the teratogenicity rate with efavirenz had to be 6.3%, or 2.3 times higher than the rate with nevirapine, for the excess number of birth defects to outweigh the additional number of women alive at 10 years.

Conclusion: In Côte d'Ivoire, initiating ART with efavirenz instead of nevirapine is likely to substantially increase the number of women alive at 10 years with a smaller potential number of birth defects.