Trends in mortality caused by respiratory distress syndrome in the United States, 1969-83

Using United States vital statistical data we examined trends in infant deaths from Respiratory Distress Syndrome/Hyaline Membrane Disease (RDS/HMD) for 1969 to 1983, by race and age at death. In order to improve comparability of diagnosis across two revisions of the International Classification of Diseases, deaths from RDS/HMD were ascertained using both underlying and associated causes of death. These data document a 2 per cent per year increase in infant mortality attributed to RDS/HMD for all races during interval I (1969-73) followed by 9 per cent per year decreases during intervals II (1974-78) and III (1979-83). However, there was a marked difference between Whites and Blacks in these trends. In the White population, RDS/HMD infant mortality increased by 2.2 per cent per year in interval I but then decreased by 10.5 per cent per year in interval II and 8.9 per cent per year in interval III. Among Blacks, on the other hand, the initial increase in RDS/HMD mortality was steeper (5.2 per cent per year) and the subsequent decreases were less (6.3 per cent per year and 8.0 per cent per year). As a result, the Black-White ratio in infant mortality attributed to RDS/HMD increased from 1.32 in 1969-73, to 1.59 in 1974-78 and to 1.72 in 1979-83. The proportion of RDS/HMD deaths that occurred in the postneonatal period increased from 1.1 per cent in interval to 3.6 per cent in interval II to 5.0 per cent in interval III. During the last interval, the decline in RDS/HMD mortality accounted for 30 per cent of the decline in overall infant mortality for both Whites and Blacks.