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The Epidemiology of Chronic Critical Illness in the United States*

Kahn, Jeremy M. MD, MS1,2; Le, Tri MS2; Angus, Derek C. MD, MPH1,2; Cox, Christopher E. MD, MPH3; Hough, Catherine L. MD, MS4; White, Douglas B. MD, MAS1; Yende, Sachin MD, MS1; Carson, Shannon S. MD5for the ProVent Study Group Investigators

doi: 10.1097/CCM.0000000000000710
Feature Articles

Objectives: The epidemiology of chronic critical illness is not well characterized. We sought to determine the prevalence, outcomes, and associated costs of chronic critical illness in the United States.

Design: Population-based cohort study using data from the United States Healthcare Costs and Utilization Project from 2004 to 2009.

Setting: Acute care hospitals in Massachusetts, North Carolina, Nebraska, New York, and Washington.

Patients: Adult and pediatric patients meeting a consensus-derived definition for chronic critical illness, which included one of six eligible clinical conditions (prolonged acute mechanical ventilation, tracheotomy, stroke, traumatic brain injury, sepsis, or severe wounds) plus at least 8 days in an ICU.

Interventions: None.

Measurements and Main Results: Out of 3,235,741 admissions to an ICU during the study period, 246,151 (7.6%) met the consensus definition for chronic critical illness. The most common eligibility conditions were prolonged acute mechanical ventilation (72.0% of eligible admissions) and sepsis (63.7% of eligible admissions). Among patients meeting chronic critical illness criteria through sepsis, the infections were community acquired in 48.5% and hospital acquired in 51.5%. In-hospital mortality was 30.9% with little change over the study period. The overall population-based prevalence was 34.4 per 100,000. The prevalence varied substantially with age, peaking at 82.1 per 100,000 individuals 75–79 years old but then declining coincident with a rise in mortality before day 8 in otherwise eligible patients. Extrapolating to the entire United States, for 2009, we estimated a total of 380,001 cases; 107,880 in-hospital deaths and $26 billion in hospital-related costs.

Conclusions: Using a consensus-based definition, the prevalence, hospital mortality, and costs of chronic critical illness are substantial. Chronic critical illness is particularly common in the elderly although in very old patients the prevalence declines, in part because of an increase in early mortality among potentially eligible patients.

Supplemental Digital Content is available in the text.

1Clinical Research, Investigation and Systems Modeling of Acute Illness (CRISMA) Center, Department of Critical Care Medicine University of Pittsburgh School of Medicine, PA.

2Department of Health Policy and Management, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA.

3Division of Pulmonary, Allergy and Critical Care Medicine, Duke University School of Medicine, Durham, NC.

4Division of Pulmonary and Critical Care Medicine, University of Washington School of Medicine, Seattle, WA.

5Division of Pulmonary Diseases and Critical Care Medicine, University of North Carolina, Chapel Hill, NC.

* See also p. 476.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (

Supported, in part, by National Institutes of Health (R01HL096651).

Dr. Kahn lectured for the National Association of Long-term Hospitals (speaking honoraria) and received support for article research from the National Institutes of Health (NIH). His institution received grant support from the NIH and the U.S. Patient-centered Outcomes Research Institute (PCORI). Dr. Hough's institution received grant support from the NIH and PCORI. Dr. Carson consulted for the Research Triangle Institute. Her institution received grant support from the NIH. The remaining authors have disclosed that they do not have any potential conflicts of interest.

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