Trends in the incidence of noncardiogenic acute respiratory failure: the role of race

Abstract

Objective: We sought to examine trends in the race-specific incidence of acute respiratory failure in the United States.

Design: Retrospective cohort study.

Setting: We used the National Hospital Discharge Survey database (1992-2007), an annual survey of approximately 500 hospitals weighted to provide national hospitalization estimates.

Patients: All incident cases of noncardiogenic acute respiratory failure hospitalized in the United States.

Interventions: None.

Measurements and main results: We identified noncardiogenic acute respiratory failure by the presence of International Classification of Diseases, Ninth Revision, codes for respiratory failure or pulmonary edema (518.4, 518.5, 518.81, and 518.82) and mechanical ventilation (96.7×), excluding congestive heart failure. Incidence rates were calculated using yearly census estimates standardized to the age and sex distribution of the 2000 census population. Annual cases of noncardiogenic acute respiratory failure increased from 86,755 in 1992 to 323,474 in 2007. Noncardiogenic acute respiratory failure among black Americans increased from 56.4 (95% confidence interval 39.7-73.1) to 143.8 (95% confidence interval 123.8-163.8) cases per 100,000 in 1992 and 2007, respectively. Among white Americans, the incidence of noncardiogenic acute respiratory failure increased from 31.2 (95% confidence interval 26.2-36.5) to 94.0 (95% confidence interval 86.7-101.2) cases per 100,000 in 1992 and 2007, respectively. The average annual incidence of noncardiogenic acute respiratory failure over the entire study period was 95.1 (95% confidence interval 93.9-96.4) cases per 100,000 for black Americans compared to 66.5 (95% confidence interval 65.8-67.2) cases per 100,000 for white Americans (rate ratio 1.43, 95% confidence interval 1.42-1.44). Overall in-hospital mortality was greater for other-race Americans, but only among patients with two or more organ failures (57% [95% confidence interval 56%-59%] for other race, 51% [95% confidence interval 50%-52%] for white, 50% [95% confidence interval 49%-51%] for black).

Conclusions: The incidence of noncardiogenic acute respiratory failure in the United States increased between 1992 and 2007. Black and other-race Americans are at greater risk of developing noncardiogenic acute respiratory failure compared to white Americans.

Figure 1

Incidence of noncardiogenic acute respiratory failure in the United States by race (1992-2007). Incidence rates are calculated using the age and sex distribution for each year as estimated by the US Census and standardized to the age and sex distribution of the 2000 US Census. Error bars represent 95% confidence intervals incorporating uncertainty of the multiple imputation process and the complex survey design of the National Hospital Discharge Survey.

Figure 2

Incidence of noncardiogenic acute respiratory failure in the United States by sex (1992-2007). Incidence rates are calculated using the age and race distribution for each year as estimated by the US Census and standardized to the age and sex distribution of the 2000 US Census. Error bars represent 95% confidence intervals incorporating uncertainty of the multiple imputation process and the complex survey design of the National Hospital Discharge Survey.

Figure 3

Percent of noncardiogenic acute respiratory failure patients who died during their hospital stay in the United States by race (1992-2007), by the number of organ failures. Estimates are based upon the mean of the multiply imputed data and the complex survey design of the National Hospital Discharge Survey. Organ failures calculated using standard definitions.(14) Error bars have been removed to improve clarity of interpretation.