The Continuum of Maternal Sepsis Severity: Incidence and Risk Factors in a Population-Based Cohort Study
et al. (2013) The Continuum of Maternal Sepsis Severity: Incidence and Risk Factors in a Population-
Based Cohort Study. PLoS ONE 8(7): e67175. doi:10.1371/journal.pone.0067175
The Continuum of Maternal Sepsis Severity: Incidence and Risk Factors in a Population-Based Cohort Study
Colleen D. Acosta 0
Marian Knight 0
Henry C. Lee 0
Jennifer J. Kurinczuk 0
Jeffrey B. Gould 0
Audrey Lyndon 0
Claire Thorne, UCL Institute of Child Health, University College London, United Kingdom
0 1 National Perinatal Epidemiology Unit, University of Oxford , Oxford , United Kingdom , 2 Department of Pediatrics, Stanford University , Palo Alto , California, United States of America, 3 California Perinatal Quality Care Collaborative, Stanford, California, United States of America, 4 Department of Family Health Care Nursing, University of California San Francisco , San Francisco , California, United States of America, 5 California Maternal Quality Care Collaborative , Stanford, California , United States of America
Objective: To investigate the incidence and risk factors associated with uncomplicated maternal sepsis and progression to severe sepsis in a large population-based birth cohort. Methods: This retrospective cohort study used linked hospital discharge and vital statistics records data for 1,622,474 live births in California during 2005-2007. Demographic and clinical factors were adjusted using multivariable logistic regression with robust standard errors. Results: 1598 mothers developed sepsis; incidence of all sepsis was 10 per 10,000 live births (95% CI = 9.4-10.3). Women had significantly increased adjusted odds (aOR) of developing sepsis if they were older (25-34 years: aOR = 1.29; $35 years: aOR = 1.41), had #high-school education (aOR = 1.63), public/no-insurance (aOR = 1.22) or a cesarean section (primary: aOR = 1.99; repeat: aOR = 1.25). 791 women progressed to severe sepsis; incidence of severe sepsis was 4.9 per 10,000 live births (95% CI = 4.5-5.2). Women had significantly increased adjusted odds of progressing to severe sepsis if they were Black (aOR = 2.09), Asian (aOR = 1.59), Hispanic (aOR = 1.42), had public/no-insurance (aOR = 1.52), delivered in hospitals with ,1,000 births/year (aOR = 1.93), were primiparous (aOR = 2.03), had a multiple birth (aOR = 3.5), diabetes (aOR = 1.47), or chronic hypertension (aOR = 8.51). Preeclampsia and postpartum hemorrhage were also significantly associated with progression to severe sepsis (aOR = 3.72; aOR = 4.18). For every cumulative factor, risk of uncomplicated sepsis increased by 25% (95% CI = 17.4-32.3) and risk of progression to severe sepsis/septic shock increased by 57% (95% CI = 40.8-74.4). Conclusions: The rate of severe sepsis was approximately twice the 1991-2003 national estimate. Risk factors identified are relevant to obstetric practice given their cumulative risk effect and the apparent increase in severe sepsis incidence.
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Competing Interests: The authors have declared that no competing interests exist.
In countries with developed healthcare systems, sepsis remains a
leading cause of preventable maternal morbidity and mortality [1].
Over the past decade the incidence of maternal deaths from severe
maternal sepsis has increased in several European countries, most
notably the United Kingdom[13]. There has also been an
increase in the incidence and severity of sepsis morbidity in the
general US and European populations[48]. While the absolute
risk of maternal death from sepsis is small in the US (0.60 per
100,000 live births in the US; extrapolated from Berg et al [9]), the
risk of severe sepsis morbidity is substantially larger (20.9 per
100,000 deliveries; extrapolated from Callaghan et al [10]).
Pregnant and peripartum women represent a particularly
vulnerable population for developing sepsis because the maternal
immune system is modulated during these periods [11]. The
systemic inflammatory response syndrome (SIRS), an indicator of
uncomplicated sepsis, is usually recognized by specific biomarkers
[12]. However, physiological changes of pregnancy can mimic and
sometimes mask these biomarkers and thus the pathophysiology of
sepsis. Recognition of an infection can therefore be delayed until
progression to severe sepsis [13]. For this reason, an understanding
of the risk factors along the continuum of sepsis morbidity from
uncomplicated sepsis to severe sepsis is important for targeting
preventive strategies that could be implemented upstream of
severe sepsis. A population-based study examining the risk factors
and outcomes of maternal sepsis morbidity has not been carried
out in the US. Further, although maternal sepsis, severe sepsis and
septic shock have been studied in isolation from one another in
other countries, there has not been a study assessing how risk
associated with these factors changes with the progression of
severity.
The aim of this study was to investigate the incidence and risk
factors of uncomplicated maternal sepsis, severe s (...truncated)