Differences among hospitals as a source of excess neonatal mortality: the District of Columbia, 1970-1978

Between 1970 and 1978 the neonatal mortality rate for black infants in the District of Columbia remained essentially constant while the national rate declined steadily. This report examines adjusted hospital-specific neonatal mortality rates in order to determine the extent to which the District's lack of improvement can be explained by excess mortality in a few hospitals. The indirect method of adjustment utilizing standardized morality ratios (SMRs) is used to control for the effect of the birth weight distribution on hospital-specific neonatal mortality rates. A generalized least squares approach is used to model the changes in the SMRs over time. No change was found in the SMRs for any hospital between 1970-72 and 1973-75, and four hospitals experienced no change in the 1973-75 to 1976-78 period (although one of these hospitals had very low SMRs initially). The remaining four hospitals experienced a 37% decline in their SMR's during the second interval (1973-75 to 1976-78). If the three hospitals that had high initial rates and showed no change in mortality rates from 1973-75 to 1976-78 had experienced the 37% decline, the District's SMR in 1976-78 would have been reduced by 20%.