Impact of race on the severity of acute episodes of asthma and adrenergic responsiveness

Abstract

Rationale: African Americans acutely ill with asthma come to emergency departments more frequently and are admitted to hospital more often than whites but the reasons are unclear.

Objectives: To determine whether such phenomena represent racial differences in attack severity or limited effectiveness of beta(2)-agonist therapy.

Methods and main results: We contrasted clinical features, airflow limitation, and albuterol responsiveness in adults acutely ill with asthma, 155 of whom where African American and 140 white, as they presented to eight emergency departments. Assessments were standardized across institutions using a care path, and admission and discharge decisions were made according to predetermined criteria. The degree of obstruction was measured by peak expiratory flow rates. The clinical features of both groups were similar. The African Americans, however, had lower flow rates (p = 0.002), and more of them experienced severe or potentially life threatening episodes (p < 0.001). Albuterol was equally efficacious in both populations and there were no differences in the post-treatment flow rates achieved irrespective of the initial attack intensity. There were no racial differences in admission/discharge ratios.

Conclusions: Our data indicate that African Americans with asthma tend to present with somewhat more intense attacks than whites, but they respond equally well to routine treatment. Similarly, there were no racial disparities in hospitalizations when standard criteria are employed.

Figures

Figure 1.

Comparison of the intensity of acute episodes of asthma in African Americans (AA) and whites (C). The left panel displays the presenting values for the peak expiratory flow rate (PEFR) expressed as a percentage of normal. The heights of the bars are mean values and the brackets represent 1 SEM. The right panel contrasts the pattern of intensity found. The heights of the bars are the percentages of the populations. Mild = PEFR > 50%; severe = PEFR ⩽ 50% of predicted; life-threatening = PEFR ⩽ 35% of predicted. The statistical probabilities for the comparisons are shown below the panels.

Figure 2.

Effect of albuterol in African Americans (AA) and whites (C). The left panel displays the absolute increase from the pretreatment baseline after albuterol in the two populations. The right panel displays the percent improvement for each group. The heights of the bars are mean values and the brackets are 1 SEM. I = Initial value; F = final value. The statistical probabilities for the comparisons are shown below the panels.

Figure 3.

Effect of albuterol in African Americans (AA) and whites (C) with different attack intensities. The heights of the bars are mean values and the brackets = 1 SEM. Mild = PEFR > 50% of predicted, severe = PEFR ⩽ 50%; life-threatening = PEFR ⩽ 35%. The statistical probabilities for the comparisons are shown below the panels.