The Epidemiology of Sepsis

Sepsis is a common and devastating syndrome that represents a significant healthcare burden worldwide. The average annual cost to care for patients with sepsis has been estimated to being $16.7 billion. Uniform definitions have been developed for the spectrum of sepsis syndrome, including the systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis and septic shock. SIRS describes the clinical manifestations derived from an acute yet nonspecific illness, whereas an infectious etiology is required for the diagnosis of sepsis. As sepsis progresses, organ system dysfunction becomes apparent (severe sepsis) with the final development of fluid refractory cardiovascular dysfunction (septic shock). Pulmonary, gastrointestinal, genitourinary, and primary bloodstream infections account for the majority of infectious sources in septic patients. Since 1987, gram positive bacteria have become the most common organisms responsible for the development of sepsis. Several risk factors for the development of sepsis have been identified including male sex, race, age, comorbid medical conditions, alcohol abuse, and a lower socioeconomic status. Seasonal variations also exist, with sepsis being more common in the winter months. Fortunately, the case fatality rates for both sepsis and severe sepsis have diminished over the last two decades. However, patients who survive their episode of sepsis continue to have increased morbidity and mortality up to five years after their initial illness.