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 and 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≥
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 ≥ 5 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 (≥ 80 years and≥
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 ≥ 65 years of age.
Nonpulmonary hazards explain short-term (31-day)