Hospital delivery volume, severe obstetrical morbidity, and failure to rescue.

BACKGROUND: In the setting of persistently high risk for maternal death and severe obstetric morbidity, little is known about the relationship between hospital delivery volume and maternal outcomes.

OBJECTIVE: The objectives of this analysis were (1) to determine maternal risk for severe morbidity during delivery hospitalizations by hospital delivery volume in the United States and (2) to characterize, by hospital volume, the risk for death in the setting of severe obstetric morbidity, a concept known as failure to rescue.

STUDY DESIGN: This cohort study evaluated 50,433,539 delivery hospitalizations across the United States from 1998-2010. The main outcome measures were (1) severe morbidity that was defined as a composite of any 1 of 15 diagnoses that are representative of acute organ injury and critical illness and (2) failure to rescue that was defined as death in the setting of severe morbidity.

RESULTS: The prevalence of severe morbidity rose from 471.2-751.5 cases per 100,000 deliveries from 1998-2010, which was an increase of 59.5%. Failure to rescue was highest in 1998 (1.5%), decreased to 0.6% in 2007, and rose to 0.9% in 2010. In models that were adjusted for comorbid risk and hospital factors, both low and high annualized delivery volume were associated with increased risk for failure to rescue and severe morbidity. However, the relative importance of hospital volume for both outcomes compared with other factors was relatively small.

CONCLUSION: Although low-and high-delivery volume are associated with increased risk for both failure to rescue and severe maternal morbidity, other factors, in particular characteristics of individual centers, may be more important in the determination of outcomes.