The Epidemiology of Acute Organ System Dysfunction From Severe Sepsis Outside of the Intensive Care Unit

Abstract

BACKGROUND: Severe sepsis is a common, costly, and complex problem, the epidemiology of which has only been well studied in the intensive care unit (ICU). However, nearly half of all patients with severe sepsis are cared for outside the ICU. OBJECTIVE: To determine rates of infection and organ sys- tem dysfunction in patients with severe sepsis admitted to non-ICU services. DESIGN: Retrospective cohort study. SETTING: A large, tertiary, academic medical center in the United States. PATIENTS: Adult patients initially admitted to non-ICU medical services from 2009 through 2010. MEASUREMENTS: All International Classification of Dis- eases, 9th Revision, Clinical Modification diagnosis codes were screened for severe sepsis. Three hospitalists reviewed a sample of medical records evaluating the char- acteristics of severe sepsis. The International Consensus Conference (ICC) for sepsis defines severe sepsis as an infection leading to acute organ dysfunction.1,2 Severe sepsis afflicts over 1 million patients each year in Medicare alone, and is substantially more common among older Americans than acute myocardial infarction.3–5 Recently, the Agency for Healthcare Research and Quality identified severe sepsis as the single most expensive cause of hospitalization in the United States.6 The incidence of severe sepsis continues to rise.4,5 Severe sepsis is often mischaracterized as a diagno- sis cared for primarily in the intensive care unit (ICU). Yet, studies indicate that only 32% to 50% of patients with severe sepsis require ICU care, leaving *Address for correspondence and reprint requests: Jeffrey M. Rohde, MD, Department of Internal Medicine, University of Michigan Medical School, 3119 Taubman Center, 1500 E. Medical Center Dr., Ann Arbor, MI 48109-5376; Telephone: 734-647-1599; Fax: 734-233-9343; E-mail: jefrohde@med.umich.edu Additional Supporting Information may be found in the online version of this article. Received: July 15, 2012; Revised: December 16, 2012; Accepted: December 26, 2012 2013SocietyofHospitalMedicine DOI10.1002/jhm.2012 Published online in Wiley Online Library (Wileyonlinelibrary.com). RESULTS: Of 23,288 hospitalizations, 14% screened posi- tive for severe sepsis. A sample of 111 cases was manually reviewed, identifying 64 cases of severe sepsis. The mean age of patients with severe sepsis was 63 years, and 39% were immunosuppressed prior to presentation. The most common site of infection was the urinary tract (41%). The most common organ system dysfunctions were cardiovas- cular (hypotension) and renal dysfunction occurring in 66% and 64% of patients, respectively. An increase in the num- ber of organ systems affected was associated with an increase in mortality and eventual ICU utilization. Severe sepsis was documented by the treating clinicians in 47% of cases. CONCLUSIONS: Severe sepsis was commonly found and poorly documented on the wards at our medical center. The epidemiology and organ dysfunctions among patients with severe sepsis appear to be different from previously described ICU severe sepsis populations.