Acute respiratory failure in the United States - Incidence and 31-day survival

Study objectives: To estimate the incidence of acute respiratory failure (ARF) in the United States and to analyze 31-day hospital mortality among a cohort of patients with ARF, Design ann setting: Retrospective cohort drawn from the Nationwide Inpatient Sample of 6.4 million discharges from 904 representative nonfederal hospitals during 1994. Patients: All 61,223 patients in the sample whose discharge records indicated all of the following: acute respiratory distress or failure, mechanical ventilation, > 24 h of hospitalization, and age greater than or equal to5 years. Results: An estimated 329,766 patients discharged from nonfederal hospitals nationwide in 1994 met study criteria for ARF, The incidence of ARF was 137.1 hospitalizations per 100,000 US residents age greater than or equal to5 years. Incidence increased nearly exponentially each decade until age 85 years. Overall, 35.9% of patients with ARF did not survive to hospital discharge. At 31 days, hospital mortality was 31.4%, According to the proportional hazards model, significant mortality hazards included age (greater than or equal to 80 years and greater than or equal to 30 years), multiorgan system failure (MOSF), HIV, chronic liver disease, and cancer. Hospital admission for coronary artery bypass, drug overdose, or trauma other than head injury or burns was associated with a reduced mortality hazard. Interaction was present between age and MOSF, trauma, and cancer. A point system derived from the hazard model classified patients into seven groups with distinct 31-day survival probabilities ranging from 24 to 99%. Conclusions: The incidence of ARF increases markedly with age and is especially high among persons greater than or equal to 65 years of age. Nonpulmonary hazards explain short-term (31-day) survival.