Economic outcome for intensive care of infants of birthweight 500-999 g born in Victoria in the post surfactant era. The Victorian Infant Collaborative Study Group.

OBJECTIVE

To determine the incremental cost of improving the outcome for extremely low birthweight (ELBW, birthweight 500-999 g) infants born in Victoria after the introduction of exogenous surfactant (the post surfactant era).

METHODOLOGY

This was a geographically determined cohort study of ELBW children in Victoria, Australia of consecutive livebirths born in three distinct eras: (i) 1979-80 (n = 351); (ii) 1985-87 (n = 560); and (iii) 1991-92 (n = 429). Exogenous surfactant was first used in Victoria in March, 1991. The consumption of nursery resources per livebirth, and the survival and sensorineural disability rates at 2 years of age for each era were investigated. Utilities were assigned as follows: 0 for dead, 0.4 for severe disability, 0.6 for moderate disability, 0.8 for mild disability, and 1 for no disability. Utilities were multiplied for more than one disability. Dollar costs were assumed to be $1470 ($A 1992) per day of assisted ventilation, and one dose of exogenous surfactant was assumed to be equivalent to one third of a day of assisted ventilation. Cost-effectiveness (additional costs per additional survivor or life-year gained) and cost-utility (additional costs per additional quality-adjusted survivor or life-year gained) ratios were calculated for the pre-surfactant era (1985-87 vs 1979-80), and for the post surfactant era (1991-92 vs 1985-87).

RESULTS

Considering only the costs incurred during the primary hospitalization, cost-effectiveness and cost-utility ratios were lower (i.e. economically better) in the post surfactant era than in the pre-surfactant era (pre-surfactant vs post surfactant; $7040 vs $4040 per life year gained; $6700 vs $5360 per quality-adjusted life year gained). Both ratios fell with increasing birthweight. In contrast with the pre-surfactant era, cost-utility ratios were less favourable than cost-effectiveness ratios in the post surfactant era. With costs for long-term care of severely disabled children added, both cost ratios were higher in the post surfactant era.

CONCLUSION

The incremental cost during the primary hospitalization of improving the outcome for ELBW infants has fallen in the post surfactant era.