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%.