Epidemiology and outcomes of acute respiratory failure in the United States, 2001 to 2009: A national survey

BACKGROUND: The objective of this study was to evaluate trends in hospitalization, cost, and short-term outcomes in acute respiratory failure (ARF) between 2001 and 2009 in the United States. METHODS: Using the Nationwide Inpatient Sample we identified cases of ARF based on International Classification for Diseases, Ninth Revision, Clinical Modification codes. We calculated weighted frequencies of ARF hospitalizations by year and estimated population-adjusted incidence and mortality rates. We used logistic regression to examine hospital mortality rates over time while adjusting for changes in demographic characteristics and comorbidities of patients. RESULTS: The number of hospitalizations with a diagnosis of ARF rose from 1, 007, 549 in 2001 to 1, 917, 910 in 2009, with an associated increase in total hospital costs from 30. 1 billion to 54. 3 billion. During the same period we observed a decrease in hospital mortality from 27. 6% in 2001 to 20. 6% in 2009, a slight decline in average length of stay from 7. 8 days to 7. 1 days, and no significant change in the mean cost per case (15, 900). Rates of mechanical ventilation (noninvasive NIV or invasive mechanical ventilation IMV) remained stable over the 9-year period, and the use of NIV increased from 4% in 2001 to 10% in 2009. CONCLUSIONS: Over the period of 2001 to 2009, there was a steady increase in the number of hospitalizations with a discharge diagnosis of ARF, with a decrease in inpatient mortality. There was a significant shift during this time toward the use of NIV, with a decrease in the rates of IMVuse.