In Reply.—We are pleased that our report "played in Peoria." We thank Dr Powers and Ms Hegwood for their remarks and comparative data. The inhospital survival rate and incidence of CLD among VLBW infants in the NCPR of Illinois appear similar to those of North Carolina.
The choice of a proper denominator for computing the incidence of CLD is indeed difficult. Our denominator (all VLBW 30-day survivors who had received mechanical ventilatory support for >48 hours) includes the infants we believe to be at risk. Thirty-day survival is a necessary criterion for at-risk status if, by definition, CLD does not exist before age 30 days. Our other criterion, mechanical ventilatory support for longer than 48 hours, is somewhat arbitrary. For that reason we also presented our data using two other denominators: all VLBW 30-day survivors and all VLBW admissions.
Powers and Hegwood are correct in pointing out that race,