To the Editor. —I read with interest the paper by Dr. Outerbridge and his associates (Journal123:99-104, 1972) concerning follow-up of premature infant survivors of the respiratory distress syndrome (RDS) during the newborn period. The authors suggest that the predisposition to severe lower respiratory tract disease observed in these infants represented a late consequence of RDS, but it is difficult to see how such a conclusion can be supported in the absence of a control group of infants who did not have RDS for comparison. A higher than expected incidence of postneonatal deaths and hospitalizations has been reported in previous studies of the expremature 1,2 but neither these studies, nor I think Dr. Outerbridge's paper, establish conclusively prior RDS as the cause. Other disadvantageous factors associated with premature birth (eg, anatomic, immunologic, sociologic) could also be of major importance. The question of the long-term prognosis of RDS is surely important