Preventing neonatal group B streptococcal disease: Cost-effectiveness in ahealth maintenance organization and the impact of delayed hospital discharge for newborns who received intrapartum antibiotics

Objectives. To estimate the cost and health benefits of implementing a risk factor-based prevention strategy for early-onset neonatal group B streptoc occal (GBS) disease, using baseline assumptions and costs from a health mai ntenance organization. With the risk factor-based strategy, intrapartum ant ibiotics (IPAs) would be provided to women with fever, prolonged rupture of membranes, or preterm labor. A second objective was to determine the impac t of an increased length of stay for well term infants with mothers who rec eived IPAs. Methods. We used decision analysis to compare the costs and benefits of the prevention strategy with usual obstetric practice for a cohort of 100 000 women and their newborn infants. We derived baseline values from a previous study based on chart review and automated cost data from a health maintena nce organization in Northern California. In sensitivity analyses, we varied baseline assumptions, including additional costs for observing well term i nfants who received IPAs. Results. If adherence to guidelines were 100%, 17% of mothers would receive IPAs at a cost of $490 000; $1.6 million would be saved by preventing 66 G BS cases (64% reduction). The net savings would be $1.1 million and 61 life -years. The net cost is sensitive to the cost of caring for well infants wh o received IPAs. If each term infant of a mother who received IPAs had 1 mo re day of observation than other term infants, there would be a net cost of $8.1 million; the cost per GBS case prevented would be $120 000 and the co st per life-year saved would be $130 000. Conclusions. Implementation in a health maintenance organization of a risk factor-based strategy to prevent neonatal GBS disease can prevent substanti al disease and be cost saving. However, if the length of hospital stay were extended among well term infants whose mothers received IPAs, the strategy would be relatively costly compared with other medical interventions.