Temporal trends and predictors of severe maternal sepsis and mortality during hospitalization for delivery
Abstract Number: GM-4
Abstract Type: Original Research
Introduction: Sepsis emerged as the leading cause of direct maternal death in the most recent Saving Mothers’ Lives report from the UK, and is reported to complicate 1:7654 to 1:8338 deliveries.(1,2,3) The population-level incidence and temporal trends are unknown in the US. The purpose of this study is to determine incidence, risk factors and outcomes for severe maternal sepsis during hospitalization for delivery using the largest administrative dataset of admissions available in the US, the Nationwide Inpatient Sample (NIS).
Methods: Admissions for delivery in women aged 12-55 were identified by the associated ICD-9CM codes for delivery and were extracted from the database during 1998-2008. Sepsis, severe sepsis (defined as sepsis and organ dysfunction) and death were identified by the presence of diagnosis codes indicating these conditions. Logistic regression analyses clustered by hospital were undertaken to determine temporal trends and independent predictors of severe sepsis, controlling for maternal demographics, obstetric complications, and hospital characteristics.
Results: Our cohort consisted of 9,245,079 admissions for delivery. Sepsis complicated 2758 deliveries (1:3351), including 855 cases of severe sepsis (23.7% of sepsis cases) and 87 deaths (3.2% of sepsis cases). While the overall incidence of sepsis does not appear to have changed over time, the rate of severe sepsis increased from 17.1% in 1998-2000 to 30.3% in 2007-2008, P=<0.001. The death rate among patients with sepsis increased during the same period from 2.2% to 4.9%, P=0.03. Factors independently associated with severe sepsis during hospitalization for delivery are: chronic renal insufficiency (aOR 21.4, 95%CI 8.8,52.0), chronic liver disease (aOR 27.6, 95%CI 10.2, 74.5), stillbirth (aOR 7.3, 95%CI 5.1,10.4) retained products of conception (aOR 6.8, 95%CI 3.8,12.2), cesarean delivery (aOR 5.2, 95%CI 4.4,6.2), hypertensive diseases of pregnancy (aOR 4.4, 95%CI 3.1,5.5), chronic heart failure (aOR 4.4, 95%CI 3.0,6.3), cerclage during pregnancy (aOR 2.5, 95%CI 1.4,4.7), and preterm delivery <37 weeks (aOR 2.0, 95%CI 1.6,2.5).
Conclusion: In this study, the rate of delivery-related sepsis was higher than previous estimates, and the rate of death and severe sepsis among parturients with sepsis increased markedly between 1998 and 2008. These trends mirror those demonstrated in the UK, and may be due to increasing virulence, or due to increasing numbers of high-risk conditions that increase susceptibility among childbearing women. Chronic renal insufficiency, chronic liver disease, stillbirth, retained products of pregnancy and cesarean delivery were among the strongest predictors of severe sepsis during hospitalization for delivery. Further research is needed to more clearly define the basis for the rise in severe sepsis during pregnancy and to develop interventions to decrease it.
1) AJOG 1988;159:410-6
2) ObstetGyncol 1997;90:553-61
3) BJOG 2011;118(S1)