ORLANDO – The rate of U.S. hospitalizations for angioedema doubled among African Americans during 2000-2009 based on a national sampling of inpatients, and the rise appears largely driven by adverse drug reactions to angiotensin-converting enzyme inhibitors.
"The rate of angioedema due to an adverse drug reaction rose from about 40% in 2000 to about 60% in 2009," said Dr. Robert Y. Lin while presenting a poster at the annual meeting of the American Academy of Allergy, Asthma, and Immunology. Adverse drug reactions "are not the only reason [that angioedema occurs], but I think it’s driving the increase."
Angiotensin-converting enzyme (ACE) inhibitors are the drugs most responsible for causing angioedema, and it seems this drug class is especially responsible for the rapid increase in the number of angioedema cases among African Americans, he said.
Among African Americans, hospitalizations for angioedema jumped from 9 cases per 100,000 in 2000 to 18 cases per 100,000 in 2009. In contrast, among non–African American residents of the United States, hospitalizations for angioedema rose from 2.7 cases per 100,000 in 2000 to 3.6 cases per 100,000 in 2009(see table).
African Americans seem particularly susceptible to developing angioedema triggered by ACE inhibitors, noted Dr. Lin. In addition, diseases that often lead to treatment with an ACE inhibitor, such as hypertension, chronic kidney disease, and heart failure, are especially prevalent among African Americans.
Angiotensin-receptor blockers, which are not linked to causing angioedema, might be a better alternative for African American patients, said Dr. Lin, a professor of medicine at New York Medical College and chief of the division of allergy and immunology at New York Downtown Hospital.
The angioedema danger from ACE inhibitors is especially insidious because it appears to be a class effect that is not dose or duration related. The side effect can occur suddenly at any time during the course of treatment. "The lag period between when you start treatment and when you see a reaction can be so variable. It can be 2 weeks, or it can be 2 years. A patient can be fine on an ACE inhibitor for months or years and then suddenly have an angioedema reaction. We don’t know why," he said in an interview.
Although angioedema is rarely fatal—the mortality rate was 0.4% in the more than 128,000 hospitalized cases that Dr. Lin tallied in his analysis—it led to an intubation rate of 8% and average hospitalization charges of about $10,000 per case. With nearly 13,000 Americans hospitalized for angioedema annually during 2000-2009, that means the annual cost was roughly $130 million.
Dr. Lin identified angioedema cases in U.S. hospitalization records collected by the Nationwide Inpatient Sample, a database maintained by the U.S. Agency for Healthcare Research and Quality. He identified angioedema cases by their ICD code. During the study period, patients hospitalized with angioedema averaged 61 years old, 61% were women, and 37% were African American. The percent of all patients with angioedema who were African American rose from 32% of cases in 2000 to 41% in 2009.
Throughout the decade studied, 56% of the angioedema cases appeared secondary to an adverse drug reaction; 61% of the angioedema patients had hypertension. Adverse drug reactions linked to hypertension or cardiovascular disease occurred in 29% of the angioedema patients overall throughout the decade studied, rising from 22% of cases in 2000 to 36% of cases in 2009. Adverse drug reactions linked to drugs used to treat hypertension or cardiovascular disease occurred overall in 38% of African American patients hospitalized for angioedema, and hit a high of 44% of African Americans hospitalized for angioedema in 2009.
Dr. Lin said that he had no disclosures.